Full opinion text
MEMORANDUM DECISION DENYING DEFENDANT’S MOTION FOR SUMMARY JUDGMENT AND RULING ON THE ADMISSIBILITY OF PLAINTIFF’S EXPERTS’ OPINIONS . MCMAHON, District Judge. This is an action to recover damages for personal injuries, sustained by Plaintiff David DeRienzo when. his: bicycle frame failed on July 4, 2001, in Newburgh, New York. Plaintiff, a New York resident, commenced this action, against Defendant Trek Bicycle Corporation (“Trek”), a Wisconsin corporation and the manufacturer of the bicycle at issue, asserting claims of negligence, breach of warranty, and strict products liability (including claims of manufacturing defect and failure- to warn). Plaintiff has withdrawn a design defect claim. (See Plaintiffs Memorandum of Law in Opposition to the Motion of Defendant Trek Bicycle Corporation for Summary Judgment, dated Feb. 2, 2004, at 1, n. 1.) Defendant requests a hearing under Federal Rules of Evidence 702 and 104(a) — a Daubert hearing — to evaluate Plaintiffs experts, and moves for summary judgment on the strict products liability manufacturing defect, failure to warn and breach of warranty claims. I. Facts Except where noted, the following facts are undisputed: Plaintiff was the rider of a used, modified 1998 Trek Y5 mountain bike (the “Bike”) that crashed on July 4, 2001 in Newburgh, New York. Defendant Trek designed and manufactured the aluminum frame on the Bike. As evidenced by the description “used” and “modified,” Plaintiff was not the original purchaser of the Bike, and, at the time of the accident, the Bike had been modified and did not consist of all original Trek components. The accident did not occur while Plaintiff was simply riding the Bike. Rather, Plaintiff was landing after jumping or dropping the Bike five to eight feet off a ledge'created by a rock sticking out of the side of a hill. It is not disputed that Plaintiff was seriously injured in the accident, although he does not elaborate on the nature or extent of his injuries. (See Complaint, dated July 31, 2002, at par. 22.) A. Plaintiffs Mountain Biking Background Plaintiff has an extensive background in mountain biking, and has ridden mountain bikes since age 12. He has mountain biked over various terrain, including the Catskill Mountains and the Swiss Alps. Plaintiff claims to have gone over hundreds of jumps and drop-offs (sometimes referred to as “drops”), and has been taken to the hospital on at least two occasions for treatment after mountain biking incidents. Around the time of the accident, Plaintiff regularly biked with four friends: Anthony Carubia, C.J. Bivona, Thomas Mueller and Anthony Conestí (collectively, the “Group”). Of the Group, Conestí and Bivona worked in bicycle shops. Plaintiff considers Conestí a mountain bike expert. During the summer of 2001, before the accident, Plaintiff stated that, on an “average” ride, he and the Group would videotape themselves riding mountain bikes and watch each other “hit jumps.” (DeRienzo Dep. at 118:12-119:2.) In addition to mountain biking, the Group also engaged in other outdoor sports together, such as surfing, skateboarding and skiing. Plaintiff apparently had a discussion about ski-jumping over a roadway with Mueller, which inspired Plaintiffs use of the name “roadgap” for a website he maintained, www.roadgap.com, which describes the Group’s sports adventures. Plaintiff participated in (and was apparently the first of the Group to try) “lake jumping,” in which the goal is to ride one’s bike off a jump into a lake. Mueller claims to have witnessed Plaintiff jumping a bike — not necessarily the Bike — into a lake at least 25-30 times. B. The History of the Bike The 1998 Trek Y5 model is a “full-suspension” mountain bike. Defendant claims the Y5 is also a “cross-country” mountain bike, (Def. 56.1 at par. 5), but Plaintiff claims it is not, (PL 56.1 at par. 5). Trek engineer Clint Kolda testified at his deposition that the Y5 was designed as a full-suspension bike that could be used for “hard” off-trail riding, but that taking a Y5 over a 5-foot drop would likely be considered a crash. (Kolda Dep. at 11:12-15.) One Jeremy Ball of Spokane, Washington was the original purchaser of the Bike and the person who sold the Bike to Plaintiff over the internet sometime in the fall of 1999. Ball told Plaintiff the Bike was “a great bike,” but he said that there were “cosmetic blemishes” on the frame. Plaintiff purchased the Bike sight unseen. When the Bike was delivered to Plaintiff, it was disassembled and wrapped in bath towels. Plaintiff reassembled the Bike himself. Plaintiff noticed some marks on the down tube, “Just like normal, like wear, like scuffs, maybe like some ping marks from maybe rocks or something like that.” (DeRienzo Dep. at 122:19-123:4.) Prior to Plaintiffs purchase, Ball had modified the Bike, though to what extent is not clear. At some time prior to the accident, Ball replaced (or had someone replace for him) the original front fork with a used “Rock Shox Triple Clamp” fork. The parties agree that the Rock Shox fork is designed to handle a heavier load from the rider, including loads created by jumps and drop-offs. In fact, a Trek catalog (Pl.Exh. 18) includes a section entitled, “Off Road,” listing the different Y model bikes (the Y5 among them) and their features, showing that the Rock Shox fork is available on certain models (but not the Y5). When Plaintiff received the Bike, it had pedal supports (“cranks”) and handlebars that were not manufactured by Trek. In fact, Defendant contends that, at the time of the accident, nothing but the frame remained of the original Bike. (Def. 56.1 Statement at par. 3.) Plaintiff disputes this but admits that at least the wheel rims, tires, brakes, gear system, pedals and handlebars had been replaced. (PI. 56.1 Statement at par. 83.) Although Ball refused to testify (or did not remember anything) about his use of the Bike prior to selling it to Plaintiff, he described himself as an “aggressive” mountain biker. Ball has raced mountain bikes all over Washington, Idaho and Montana, and has described his typical course as being “rocky,” with jumps measuring two to eight feet and drop-offs measuring three to twelve feet. Ball estimates that he has fallen about 1,000 times using various mountain bikes. Of those 1,000 incidents, he estimates that he flew over the handlebars 30-50% of the time. It is not clear how many of these incidents, if any, involved the Bike at issue in this case. During the two years before the crash, Plaintiff rode the Bike at least every other day, and sometimes daily. He estimates that he put more than 1,000 miles on the Bike. Plaintiff engaged in three different types of riding: “urban assault” riding, dirt jumping and mountain biking. While urban assault riding, Plaintiff stated that he and the Group would ride around at night through the streets of Newburgh and Poughkeepsie and “jump off ledges and stuff.” (DeRienzo Dep. at 69:17-18.) Coneski stated in his deposition that he thought Plaintiff enjoyed urban assault riding more than other types of riding. Coneski also stated that Plaintiff “really liked jumping .off stuff’ and that he witnessed Plaintiff performing more than 500 jumps and drops. Coneski does not indicate whether any of these 500 jumps and drops involved the Bike at issue here or whether some were made using other bikes. Coneski acknowledged that landing on concrete is “really harsh” on a bicycle frame and said that Plaintiffs urban assault riding was “a little rough.” Plaintiff did “dirt jumping” with the Bike, which, according to Coneski, “is where you go to a stop where there’s two dirt jumps, where there’s a lip and a landing and just do that all day or as long as you want. That’s dirt jumping.” (Coneski Dep. at 217:25-218:4.) Plaintiff and the Group jumped their bikes four or five times a week in an area where they built eleven dirt ramps. The tallest ramp was five feet high. Coneski testified that he only saw Plaintiff damage a bike one other time before the accident — “I seen him bend a wheel real bad in the front once” — • but Coneski did not indicate whether Plaintiff was riding the subject Bike at the time. (Coneski Dep. at 234:16-235-24.) In addition to urban assault riding and dirt jumping, Plaintiff used the Bike for mountain biking or “off-road” riding. Plaintiff estimated that he took the Bike over approximately 200 jumps and drop-offs before the accident, with the highest being ten feet off the ground. Coneski stated in his deposition that in his (non-expert) opinion, Plaintiffs use of the Bike put the Bike close to, or possibly past, the point where the aluminum frame would be “stressed.” The day before the crash at issue in this case, Plaintiff was involved in an incident in which the front wheel of the Bike hit the ground at an angle of between 50 and 70 degrees, causing Plaintiff to go flying over the handlebars. Plaintiff claims not to have been injured in this incident. C. The Owner’s Manual and Warning Sticker The parties dispute almost everything about the Owner’s Manual and warning stickers. Each party submitted a different version of a Trek Owner’s Manual with its moving papers. The version submitted by Defendant contains sterner, more prominent warnings about the dangers of various aspects of mountain biking than the version submitted by Plaintiff. It is not clear which version actually was issued with the Bike when Ball purchased it, and Plaintiff did not produce any Owner’s Manual that was in his possession during discovery. If an Owner’s Manual was issued to Ball when he first purchased the Bike, it is not part of the record. Plaintiffs Exhibit 14 is a Trek “All-Terrain Bicycle Owner’s Manual” that, according to an email from defense counsel (attached to the copy of the Owner’s-Manual in PI. Exh. 14), “would have accompanied most 1998 Trek Y-5 bicycles when they were purchased new.” This Owner’s Manual is copyrighted 1997 by Trek and carries the notation, “Trek P/N 971475.” I will refer to this as the “1997 Manual.” Defendant’s Exhibit 3 is also a Trek “All-Terrain Bicycle Owner’s Manual.” It appears similar to Plaintiffs Exhibit 14. However, Defendant’s version is copyrighted 1998 and carries the notation, “Trek # 990264.” I will refer to this version as the “1998 Manual.” The 1997 and 1998 Manuals contain substantially different warnings. For example, page 2 of the 1998 Manual has a'box at the bottom of the page that shows the word, “WARNING” in bold against a dark background, with a “!” symbol on a dark triangle. I will refer to the combination of “WARNING” with the “!” on the triangle, bold and highlighted, as the “Warning Sign.” The Warning Sign is accompanied .by the following text: “Read Chapter 1 now! It contains important safety information which you should read thoroughly before you ride your new bicycle.” Page 3 shows the Warning Sign at the bottom of the page with the following text: “In this manual, the warning sign indicates there is the possibility of death or serious injury if an error is made in handling or operation.” Page 5 shows the Warning Sign arid states, “Before you ride your new bike, you should read this entire chapter. It includes safety, operational, and riding information that you should know before riding your new bicycle!” Page 6 shows the Warning Sign and states, “This is not a comprehensive maintenance program. Check the entire, bicycle carefully. If you spot a problem, do not ride the bike until it has been corrected. If you are not certain if your bike has a problem, take your bike to your Trek dealer.” Page 15 states, with the Warning Sign, “Never modify your frameset in any way, including sanding, drilling, filing, or by any other technique. Such modifications will void your warranty, may cause your frame to fail, and may contribute to loss of control resulting in personal injury.”' The same text appears on page 55 with the Warning Sign. In fact, the 1998 Manual contains the Warning Sign with various accompanying text on 23 of its 56 pages (occasional pages show two Warning Signs with different text). By contrast, the 1997 Manual does not contain any Warning Sign logos, although it does contain some of the same text. Page 2 has text in a box that says, “IMPORTANT! — Read Chapter 1 now! It contains important safety information which you should read thoroughly before you ride your new bicycle.” This is the same text as the warning on page 2 of the 1998 Manual, but without the Warning Sign. As there are no Warning Sign logos in the 1997 Manual, there is no analogous warning to the one on page 3 of the 1998 Manual that the Warning Sign indicates risk of “death or serious injury if an error is made in handling or operation.” On page 5 of the 1997 Manual, a text box states: “IMPORTANT! Before you ride your new bike, you should read this entire chapter. It includes safety, operational, and riding information that you should know before riding your new bicycle!” This is similar to the warning on page 5 of the 1998 Manual. Page 6 states, “IMPORTANT: This is not a comprehensive maintenance program. Check the entire bicycle carefully. If you spot a problem, do not ride the bike until it has been corrected. If you are not certain if your bike has a problem, take your bike to your Trek dealer.” This is the same text that appears on page 6 of the 1998 Manual. Page 12 states, ‘WARNING: Never modify your frameset in any way, including sanding, drilling, filing, or by any other technique. Such modifications will void your warranty, may cause your frame to fail, and often contribute to a loss of control resulting in a personal injury.” Page 48 contains a substantially similar warning. The warnings on pages 12 and 48 of the 1997 Manual are similar to the warnings that appear on pages 15 and 55 of the 1998 Manual. In addition, page 22 of the 1997 Manual contains a text box that states, “CAUTION: Never ride any bicycle that is not operating properly.” The Court could not find a similar warning in the 1998 Manual (other than the text in the warnings on page 6 of both Manuals). The 1997 Manual contains text boxes with the words, “CAUTION,” “WARNING” or “IMPORTANT” on 21 of its 52 pages. The most important warning in the 1998 Manual — for purposes of this case — is found on page 12 and takes up approximately 1/3 of the page. It states (with the Warning Sign): Jumping your bicycle, performing bicycle stunts, severe off road riding, downhill riding, or any abnormal bike riding can be very dangerous. These activities increase the stress on your frame and components and can lead to premature or sudden failure of your bicycle frame or components. Such failure could cause a loss of control resulting in serious injury or death. Industry pictures and videos of these kinds of activities depict very experienced or professional riders. If you choose to jump your bicycle, use it for stunts, or use it in a severe offroad [sic] or downhill environment, carefully inspect your frame and components for signs of fatigue before and after each ride. Remember; it is much easier to have an accident resulting in serious personal injury in these situations even if your bicycle performs as intended. Use suitable protective gear, including a certified bicycle helmet. The only “warning” about jumping in the 1997 Manual is at the very bottom of page 10, in regular text (with no text box, Warning Sign or other graphic) and takes up approximately 1/10 of the page. It states in full: “Avoid jumping. Bicycles are not made for jumping. Doing so may cause your frame to fail. Never ride your bicycle in such a manner as to propel your bicycle airborn [sic], including riding over steps and curbs.” This “Avoid jumping” text is the last of five text segments on page 10, the other four being (in order, from top to bottom): “Wear a helmet,” “Know and observe your local bicycle riding laws,” “Use special care when off-road riding,” and “Use good shifting techniques.” On the opposite (facing) page, there is a text box with the word “CAUTION” and two segments (including bold text) about the dangers of riding at night and in wet conditions. On page 20, there is a list of the IMBA Rules of the Trail In sum, the warnings on pages 2, 5, 6, 12 and 48 of the 1997 Manual are analogous to the warnings on pages 2, 5, 6, 15 and 55 of the 1998 Manual, except that the warnings in the 1998 Manual are accompanied by Warning Signs and the ones in the 1997 Manual are not. The warning about the specific dangers of jumping is unique to the 1998 Manual, as is the warning that “death or serious injury” could result from errors in operating a bicycle. The freestanding warning against riding a bicycle that is not operating properly is unique to the 1997 Manual, as is the very brief and inconspicuous warning not to jump a bicycle. Interestingly, the 1998 Manual, which contains the more conspicuous and arguably more severe warning about jumping, does not state that a Trek bicycle should not be used for jumping. The 1997 Manual, by contrast, flatly (though inconspicuously and briefly) states that bicycle should not be used for jumping, but fails to state what the dangers of doing so would be. Ball testified that he does not remember whether he ever got a Y5 Owner’s Manual when he originally bought the Bike, and he does not remember whether he sent any literature with the Bike when he sold it to Plaintiff. (Ball Dep. at 50:12-18.) When asked if he received an Owner’s Manual with the Bike when he bought it from Ball, Plaintiff stated, “I don’t think so.” (DeR-ienzo Dep. at 106:17-19.) Defendant also claims in its 56.1 Statement, pars. 7 and 8, that the 1998 Y5 model came with a sticker on the frame, reading: WARNING! NEVER RIDE YOUR BICYCLE WITHOUT A HELMET. YOUR OWNER’S MANUAL CONTAINS CRITICAL SAFETY INFORMATION. READ YOUR OWNER’S MANUAL BEFORE YOU RIDE THIS BICYCLE. IF YOU DON’T HAVE AN OWNER’S MANUAL, SEE YOUR LOCAL DEALER. Defendant included copies of the sticker as Def. Exhibit 4. However, the copies are not evidence in support of the assertion that the stickers were placed on this Bike in 1998, and Defendant’s 56.1 Statement cites no testimony from anyone at Trek to the effect that stickers were affixed to any 1998 models of the Y5. Therefore, the assertion does not comply with Local Rule 56.1, which requires that, “Each statement by the movant or opponent pursuant to Rule 56.1(a) and (b), including each statement controverting any statement of material fact, must be followed by citation to evidence which would be admissible, set forth as required by Federal Rule of Civil Procedure 56(e).” (Emphasis in original.) D. The Accident On July 4, 2001, Plaintiff was riding with Mueller, Cambia and Conestí in a wooded area on Cronomer Hill in Newburgh, New York. Cambia was videotaping the others going over jumps and drop-offs. Prior to the accident, Plaintiff had been riding for more than one hour. During that time, Plaintiff did between eight and ten drops. At one point prior to the accident, the riders approached a drop from a large rock onto a ladder bridge. According to Conestí, Plaintiff contemplated the drop for about twenty minutes and then decided not to do it because, “It just freaked him out.” (56.1 Statements at par. 95.) The riders subsequently approached the area where the accident occurred, a drop-off of between five and eight feet created by a boulder approximately the size of a car sticking out of the side of Cronomer Hill. Defendant states, in par. 99 of its 56.1 Statement, without citation, that, “Trees and bushes flank the cliff on both sides.” Plaintiff disputes this, but also provides no citation to contrary evidence. Defendant cites the Expert Report of Gerald P. Bret-ting, P.E., for the assertions that the area leading up to the cliff is angled downward at 18 degrees, and that the landing area is angled downward at 30 degrees. (Def. 56.1 Statement at pars. 100-101.) Plaintiff disputes this, (pars. 100 and 101 of PI. 56.1 Statement), citing only Mueller’s testimony that the slope of the ground leading up to the cliff is “Maybe 10-15 degrees. Not a big slope,” (Mueller Dep. at 242:3-7), and Coneski’s testimony that the “take-off’ area is “nice flat rock.” (Conestí Dep. at 314:9-14.) Defendant paraphrases (with some errors) the testimony of Conestí regarding the landing area. (Def. 56.1 at par. 102.) Coneski’s testimony about the landing area was that there are some rocks and roots, because it’s not a pretty high drop. Four feet or whatever, it isn’t that high. But you land on pretty choppy stuff... It’s not real bad, but it’s a little choppy... [The rocks are] pretty big, but they’re in the ground. Just the tops are sticking up. And there’s one root that comes right across. (Coneski Dep. at 313:9-314:2.) According to Coneski, the “coolest part” of this drop is that the rider cannot see the landing area until his bike is already off the boulder. For this reason, the riders used twigs to indicate where the perfect landing spot would be. Specifically, Coneski stated: We’ll take two twigs and make like a little, narrow spot. Because you can’t tell from up top. When you’re up top all you can see is the top, and the ground is gone... We brushed stuff away [from the landing area] with our feet... [T]here was like a groove that went right through the rocks, and we put twigs there and kind of lined it up. (Coneski Dep. at 317:25-318:17.) Plaintiff was the first to go over the drop where the accident occurred. When Coneski was asked whether Plaintiff was “trying to go first to prove himself again, because he hadn’t done the previous drop,” Coneski replied, “Maybe. I don’t know.” (Coneski Dep. at 381:18-21.) Plaintiff approached the takeoff area from about thirty feet away. Plaintiff believed he needed to approach the drop with “a good amount of speed” in order to avoid somersaulting. Coneski thought Plaintiff was approaching the drop too slowly and worried that Plaintiff would land the front wheel first. Coneski stated in his deposition that he cannot do drops as slowly as Plaintiff was approaching this drop because his “front end dies.” While in the air, Plaintiff believed the Bike was “fairly level” to the landing surface. And at some other point during the jump, the front end of the Bike tipped down towards the ground. Plaintiff does not recall what part of the Bike hit the ground first. Mueller and Coneski viewed the accident (what they could see of it) from behind (ie., up the hill from the boulder, since DeRienzo was the first to go over the drop). Mueller stated that Plaintiffs “front end gradually dropped.” Coneski stated that Plaintiffs “front wheel was pretty low” and “too low” while Plaintiff was in the air. Coneski also characterized Plaintiffs body position as he took off as “a little forward” but he also stated that “everything else was okay,” and that Plaintiff did “everything right to try to fix” his position in the air. Specifically, Coneski said Plaintiff put his body “really, really far back trying to pull the front end up.” (Coneski Dep. 384:9-21.) Plaintiff thinks that “the bike broke like almost exactly when I somehow touched the ground.” (DeRienzo Dep. 176:4-6.) He does not know if any part of the Bike hit a rock as he landed. (Id. at 175:17-24.) Coneski did not see the frame break, but he stated that he thought the frame broke when Plaintiff hit the ground on landing. (56.1 Statements at par. 125.) Mueller stated that he saw Plaintiff land the Bike front wheel first, but the Court cannot locate any testimony about whether Mueller saw the frame break. Plaintiff stated that he “first realized the bike had broke [sic] when I was sitting there and my face felt like it was on fire and my friend Thomas [Mueller] was like, ‘Don’t move.’ He is like, ‘Your bike just broke.’ ” (DeRienzo Dep. 176:17-21.) Plaintiff realized he had gone over the handlebars when he woke up, but he didn’t remember actually going over. (Id. at 176:25-177:16.) Plaintiff testified that, had the frame, not broken, “I am absolutely positive I would have landed successfully.” (DeRienzo Dep. at 177:6-7.) Coneski stated that he had “seen people land front wheel like that and have no problem.. So that’s; — I don’t know if he crashed because of the .frame or if it really was totally his fault.” (Coneski Dep. at 393:17-21.) II. Summary Judgment Standard A party is entitled to summary judgment when there is no “genuine issue of material fact,” and the undisputed facts warrant judgment for the moving party as a matter of law. Fed.R.Civ.P. 56(c); Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 106 S.Ct. 2505, 91 L.Ed.2d 202 (1986). In addressing a motion for summary judgment, “the court must view the evidence in the light most favorable to the party against whom summary judgment is sought and must draw all reasonable inferences in [its] favor.” Matsushita Elec. Indus. Co. Ltd. v. Zenith Radio Corp., 475 U.S. 574, 587, 106 S.Ct. 1348, 89 L.Ed.2d 538 (1986). Whether any disputed issue of fact exists is for the Court to determine. Balderman v. United States Veterans Admin., 870 F.2d 57, 60 (2d Cir.1989). The moving party has the initial burden of demonstrating the absence of a disputed issue of material fact. Celotex v. Catrett, 477 U.S. 317, 323, 106 S.Ct. 2548, 91 L.Ed.2d 265 (1986). Once such a showing has been made, the non-moving party must present “specific facts showing that there is a genuine issue for trial.” Fed.R.Civ.P. 56(e). The party opposing summary judgment “may not rely on conclusory allegations or unsubstantiated speculation.” Scotto v. Almenas, 143 F.3d 105, 114 (2d Cir.1998). Moreover, not every disputed factual issue is material in light of the substantive law that governs the case. “Only disputes over facts that might affect the outcome of the suit under the governing law will properly preclude summary judgment.” Anderson, 477 U.S. at 248, 106 S.Ct. 2505. III. Discussion The key to understanding this case is as follows: Plaintiff alleges that he performed the jump in a manner that would have resulted in a successful landing — like all the landings before it — -had the Bike frame not failed. Plaintiff further argues that Defendant knew people were using the Y5 model for jumping but that it was not designed or reasonably fit for that use, and that Defendant failed to adequately warn of this danger. Defendant argues, to the contrary, that Plaintiff would have fallen on this occasion even if the frame had not failed, because of his poor position in the am, and that it was Plaintiffs history of misusing the Bike — and not a defect — that made it susceptible to failure on this particular occasion. Defendant implies that the failed jump caused the frame to break, and not the other way around. Defendant also argues that it did not market the Y5 model for jumping, that it did warn of the dangers of jumping a Y5 model bike, and that Plaintiffs failure to read any such warnings is fatal to his claims. Most important, Defendant asserts that Plaintiff has not adduced evidence sufficient to raise a genuine issue of material fact concerning what caused the accident. As discussed below, I disagree. Each of the challenged claims— manufacturing defect, failure to warn and breach of warranty — requires proof that the accident was caused by a failure of the Bike’s frame. See, e.g., Voss v. Black & Decker Mfg. Co., 59 N.Y.2d 102, 106, 463 N.Y.S.2d 398, 450 N.E.2d 204 (1983); Gilks v. Olay Co., Inc., 30 F.Supp.2d 438, 443 (S.D.N.Y.1998). Since there are scientific and technical issues involved in this determination, expert proof is required. See, e.g., Tiner v. General Motors Corp., 909 F.Supp. 112, 117 (N.D.N.Y.1995) (citing Food Pageant, Inc. v. Consol. Edison Co., 54 N.Y.2d 167, 445 N.Y.S.2d 60, 429 N.E.2d 738 (1981)). Thus, if plaintiff cannot show that the failure of the Bike frame caused the accident (an assertion that requires the support of admissible expert testimony), the case is over, under any theory. See, e.g., Clarke v. Helene Curtis, Inc., 293 A.D.2d 701, 701-02, 742 N.Y.S.2d 325, 326-27 (2d Dep’t 2002) (granting summary judgment where défendant established its prima facie entitlement to summary judgment by demonstrating that there was no causal link between its product and plaintiffs injuries and plaintiffs expert’s report was “speculative and conelusory” and “devoid of any reference to a foundational scientific basis”). Since no one who was present at the time and place of the accident has testified that he observed the frame break apart, no one who was there offers any evidence about causation, and Plaintiff does not argue otherwise. Rather, Plaintiff offers the testimony of two experts that, taken together, purportedly add up to a hypothesis that the failure of the frame caused the accident. As discussed below, I find that the opinion of Plaintiffs metallurgical expert, Harold W. Paxton, Ph.D. — that the frame failed because .of a defect — gives rise to the reasonable inference that the frame failure caused Plaintiffs accident. Thus, in order to address the most important question first — causation—I will evaluate Paxton’s qualifications and methodology first. Because Paxton opines on the existence of a defect, I address the sufficiency of Plaintiffs strict products liability manufacturing defect proof, with respect to summary judgment, at the same time. Plaintiffs second expert is John S. Allen, an electrical engineer with extensive experience in the areas of cycling, cycling safety, and trends in cycling. While Allen offers an opinion that the failure of the Bike frame caused Plaintiffs accident, for the reasons discussed below, I find that he is not qualified to give such testimony. Allen’s Report also addresses the questions of whether Trek marketed the Y5 for jumping, and whether Trek adequately warned of the dangers of using a Y5 for jumping, areas in which Allen is qualified to testify. I address the sufficiency of Plaintiffs proof for his failure to warn and breach of warranty claims when I evaluate Allen’s qualifications and methodology. A. Evaluation of Experts Generally An evaluation of expert testimony begins with Federal Rule Evidence 702, which states: If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case. Rule 104(a) states in part that, “Preliminary questions concerning the qualification of a person to be a witness... or the admissibility of evidence shall be determined by the court.” Historically, expert scientific testimony was inadmissible unless it was derived from “generally accepted” scientific techniques. See Frye v. United States, 54 App. D.C. 46, 47, 293 F. 1013, 1014 (1923). Rejecting the Frye standard as too restrictive, but reasoning that Rule 702 “clearly contemplates some degree of regulation of the subjects and theories about which an expert may testify,” the United States Supreme Court articulated a new standard in Daubert v. Merrell Dow Pharmaceuticals, Inc., a toxic tort case involving the question of whether the prescription drug Bendeetin caused birth defects. 509 U.S. 579, 589-90, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993). Under Daubert, a trial court “[f]aced with a proffer of expert scientific testimony” must determine, pursuant to Rule 104(a), whether the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue. This entails a preliminary assessment of whether the reasoning or methodology underlying the testimony is scientifically valid and of whether that reasoning or methodology properly can be applied to the facts in issue. Id. at 592-93, 113 S.Ct. 2786. Thus, the testimony “must be supported by appropriate validation” and must have “a valid scientific connection to the pertinent inquiry,” but it does not necessarily have to be “generally accepted.” Id. at 590, 113 S.Ct. 2786. Simply put, the testimony must be scientifically valid and relevant to the case at hand. See, e.g., Daubert v. Merrell Dow Pharmaceuticals, Inc., 43 F.3d 1311, 1315-16 (9th Cir.1995) (“Daubert II”). Two key factors in performing a Daubert analysis are whether the scientific technique can be tested, and whether it has been subjected to peer review and publication. Daubert, 509 U.S. at 580, 113 S.Ct. 2786. Two other factors bearing on the 'inquiry are “the known or potential rate of error” and the “existence and maintenance of standards controlling the technique’s operation.” Id. at 594, 113 S.Ct. 2786. Referring to Frye, the Daubert Court stated, “A ‘reliability assessment does not require, although it does permit, explicit identification of a relevant scientific community and an express determination of a particular degree of acceptance within the community.’ ” Id. Finally, the Daubert Court noted that the standard under Rule 702 is a flexible one, focused “solely on principles and methodology, not on the conclusions they generate.” Id. at 595, 113 S.Ct. 2786; see also Amorgianos v. Nat’l R.R. Passenger Corp., 303 F.3d 256, 265 (2d Cir.2002) (cited in Wantanabe Realty Corp. v. City of New York, No. 01-Civ.-10137 (LAK), 2004 WL 188088 at *2 (S.D.N.Y. Feb. 2, 2004)) (noting that “a district court should consider the indicia of reliability, including, but not limited to, (1) whether the testimony is grounded in sufficient facts, (2) whether the underlying methodology is rehable, and (3) whether the witness has applied the methodology reliably to the facts”). The Supreme Court clarified Daubert in two subsequent cases, General Electric Co. v. Joiner, 522 U.S. 136, 118 S.Ct. 512, 139 L.Ed.2d 508 (1997), also a toxic tort case, and Kumho Tire Co., Ltd. v. Carmichael, 526 U.S. 137, 119 S.Ct. 1167, 143 L.Ed.2d 238 (1999), a products liability-case. In Kumho Tire, a car’s tire blew out, resulting in an accident that killed one passenger and injured others. Plaintiffs sued the manufacturer, alleging that the tire was defective. Plaintiff relied on the testimony of an engineer who had written a report based on “visual and tactile inspection” of the blown tire. Id. at 155, 119 S.Ct. 1167. The trial court applied the Daubert factors listed above and found that the engineer’s report lacked sufficient indicia of reliability. Id. at 145, 119 S.Ct. 1167. The Eleventh Circuit reversed, holding that Daubert did not apply to nonscientific expert opinions. The Supreme Court reversed the Eleventh Circuit, finding (i) that one or more of the four Da%i-bert factors may be applied to experience-based expert reports, and (ii) that the trial court’s “gatekeeping” function created by Daubert applies to all expert testimony, not just scientific expert testimony. Id. at 147-51, 119 S.Ct. 1167. The Court stated that the object of Rule 702 “is to make certain that an expert, whether basing testimony upon professional studies or personal experience, employs in the courtroom the same level of intellectual rigor that characterizes the practice of an expert in the relevant field.” Id. at 152, 119 S.Ct. 1167. Noting that “there are many different kinds of experts, and many different kinds of expertise,” the Kumho Tire Court honed the Daubert inquiry for experience-based expert testimony to include examination of how often an experience-based methodology has produced erroneous results and whether such a method or preparation is generally accepted in the relevant community. 526 U.S. at 151, 119 S.Ct. 1167. The proponent of expert testimony bears the burden of proving the admissibility of that testimony by a preponderance of the evidence. See, e.g., Baker v. Urban Outfitters, Inc., 254 F.Supp.2d 346, 353 (S.D.N.Y.2003). Because Plaintiff has supplied the Expert Reports, testimony, background and professional associations of Paxton and Allen, I find that further submissions by the parties would not add to my analysis. Accordingly, I conduct the Daubert hearing on the papers. See, e.g., Wantanabe, supra, 2004 WL 188088 at *1 n: 1 (finding witness’s trial testimony in the form of a deposition taken de bene esse, an earlier deposition and the expert’s written report provided sufficient information for the court to rule on the admissibility of that expert’s testimony); Anderson v. Hedstrom Corp., 76 F.Supp.2d 422, 436-37 (S.D.N.Y.1999) (addressing an issue fully briefed by the parties where the court had no reason to believe any new information would be presented in the future); see also Greenwood v. Koven, 880 F.Supp. 186, 191-92 (S.D.N.Y.1995) (concluding that it would be wasteful not to decide an issue that the parties had had a full opportunity to brief). B. Harold W. Paxton (Manufacturing Defect, Causation) Plaintiff offers the opinion of Harold W. Paxton, Ph.D, that the Bike frame failed due to a defect — a fatigue crack that propagated through the frame’s down tube, caused by excess weld metal that was deposited on the interior of the tube at the weld cite during the manufacturing process. (Report of Harold W. Paxton, Ph.D., PI. Exh. B, at 10.) 1. Paxton’s Qualifications, Methodology and Conclusions Harold W. Paxton, Ph.D., is the U.S. Steel University Professor (Emeritus) of Metallurgy and Materials Science at Carnegie Mellon University. Paxton is a Fellow of the American Association for the Advancement of Science, the American Society for Metals, the American Society for Metals and the Mining, Metallurgical and Materials Society of AIME (TMS), as well as a member of the National Academy of Engineering and the Directors of Industrial Research. A consultant to industry and author of many technical papers, primarily in the field of physical metallurgy, Paxton has been a guest lecturer around the world and has received multiple ■ international honors in the field of metallurgy. ■ (See PI. Exhs. 2, A.) Paxton’s Report, dated June 20, 2003, includes the following information about his methodology and testing of Plaintiffs Bike:. The Bike was delivered to him on January 4, 2002 and was in his uninterrupted possession until December 17; 2002. Shortly after receipt, he carried out a preliminary non-destructive examination, involving inspection of the fracture site at low magnification, and photographic recording of selected areas. This inspection revealed that the fracture showed three parts. There was an apparent crack at the edge of the weld zone (15 mm) at the topmost point of the tube and immediately contiguous to the weld with no smooth curvature where the weld met the tube. Well-defined “shear lips” were visible roughly parallel to the sides of the weld but separated from it. Finally, there was a tear through the remainder of the frame tube, which allowed complete separation of the Bike into two pieces held together only by cables. (Paxton Rep. at 2.) These preliminary observations required destructive evaluation for confirmation, leading to the development of a testing protocol agreed upon with the defense team. (The protocol is attached as Appendix A to Paxton’s Report.) According to the Report (p. 3), a metallurgical expert for Defendánt, David Williams, and defense counsel agreed on a protocol to be carried out at MATCO Associates. Following the protocol, the cylindrical section attached to the upper frame member was removed from the post that connects the front fork to the handlebars, recorded at each stage photographically by the defense (and the photographs were provided to Paxton.) The other side of the fracture, the upper frame member, was significantly deformed at both ends of the major axis of the elliptical tube frame during the crash, and was thus set aside to provide material for chemical analysis and mechanical testing. Optical microscopy (not defined in the Report, but evidently, from the text of the analysis, a visual inspection of the fracture site with magnification) was also performed at MATCO. The Report includes photographs and illustrations of this procedure. Paxton concluded that the “grain size” was “larger than in the bulk,” and that “when Trek welded the subject frame enough heat was applied locally for a longer time than normal from an excess of weld metal such that the grain size was increased.” (Report p. 6.) He also concluded that, “Virtually all of the hardness measurements” near a tested weld site were below those expected for the type of aluminum used in this frame (6061 aluminum) at that weld juncture. (Id.) . Based on these results, Paxton states that he and the defense reached a decision to perform destructive testing on the actual fracture to learn more. (Report at p. 8.) The procedure is described as follows: Figure 12 shows the attachment of the “down tube” to the “head tube”. Previous examination was on the other (mating) half of the fracture, and on Weld II. A and B are areas of excess weld metal which had penetrated during assembly. A is adjacent to the fracture and is shown more clearly in Figure 13. B, shown also in Figure 14, was at the bottom of the attachment and was not examined further. The lines 1, 2 and 3 were where cuts were made to enable examination. The cut along line 1 roughly parallel to the fatigue fracture (Figures 15 and 16) served principally to enable cuts to be made along lines 2 and 3. [Figures 12-17 are photographs of the fracture site taken from various angles, and showing where lines had been drawn on the actual metal to indicate where the cuts would be made to analyze the metal around the fracture.] The cut along line 3 is shown in Figure 17. The sample was polished, examined in the unetched state and then etched in modified Poulton’s reagent prior to photography. Part of the head tube was discarded for convenience prior to mounting. A view of the cut along line 2 is shown in Figure 18. The smaller piece was used for metallographic examination. The excess weld metal (A) is clearly visible. At a higher magnification, one may also see an imperfect joint between excess weld metal A and the down tube, which in effect serves as a crack which propo-gates into the weld metal... Cut 2 deliberately did not pass through the center of A, and thus a further grinding of some 1 mm. was carried out, with further metallography to allow some 3-D appreciation to be obtained. .. (Id.) Based on these tests, Paxton reached the following conclusions: The bike -failed by a classical fatigue crack which propagated through the down tube until the static load could not be supported and the tube tore. Both [of the welds that were examined] showed that excess metal deposited on the interior during the welding process caused a variety of cracks. In particular, we note that the areas near the fracture show several types of cracks or tears created by uncontrolled welding in the manufacturing process, any of which could have propagated, but were preempted by the crack which actually did propagate to failure. The relatively low hardness, corresponding to lower strength, allowed fatigue to occur more readily. I do not mean to imply that all TREK bikes would suffer from the inadequacies of the DeRienzo model, but this particular machine did not receive the manufacturing quality which is expected by following TREK’s prescribed processes. In my view, with a reasonable degree of scientific certainty, the presence of excess weld metal which could not be detected by the TREK standard external inspection was a substantial factor in causing the fatigue crack. (Report p. 10.) One of Defendant’s overarching criticisms of Paxton is that he has done no research on the subject of aluminum since the mid-1960’s, has never done analysis of aluminum welds or fatigue cracks, has never observed testing of aluminum welds, and has only a “general understanding” of the authoritative research that has been done on aluminum weld integrity. (Id.) According to Defendant, Paxton does not have “the faintest idea” about the mountain biking industry and has never analyzed a bicycle frame failure. (Id. at 12.) While it appears that most of Paxton’s research has focused on steel, I find that his extensive education and teaching background in the field of metallurgy generally, as well as his broad and prestigious professional associations, indicate that he is qualified to undertake analysis of an aluminum bicycle frame like the one in this case. He is a distinguished professor of metallurgy with many years’ experience, multiple awards and many publications in the field. The fact that Paxton has more experience analyzing steel than aluminum goes to the weight of his testimony. See, e.g., Byrne v. Gracious Living Industries, Inc., No. Ol-Civ-10153 (LAK), 2003 WL 446474 at *1 n. 1 (S.D.N.Y. Feb. 25, 2003). Paxton’s testimony is also offered for a proper purpose. He offers a scientific opinion that may help the trier of fact determine an ultimate issue in the case: namely, what caused the'Bike’s frame to fail. See, e.g., LinkCo, Inc. v. Fujitsu Ltd., No. 00-Civ-7242 (SAS), 2002 WL 1585551 at *1 (S.D.N.Y. July 16, 2002) (noting that expert testimony is admissible when it helps a jury understand facts that are “outside common understanding”). Paxton’s opinions address only the question of why the Bike frame failed (and not whether the frame failure caused Plaintiff to fall), but that is no bar to admissibility. Moreover, a reasonable inference can be drawn that a defective frame would have caused the accident. See, e.g., Jarvis v. Ford Motor Co., 283 F.3d 33, 45-46 and n. 6 (2d Cir.2002) (finding that existence of a “causative defect” can be inferred from circumstantial evidence) (quoting Hunter v. Ford. Motor Co., 37 A.D.2d 335, 325 N.Y.S.2d 469, 471 (3d Dep’t 1971)). Defendant’s specific criticisms of Pax-ton’s Report begin with the comment that Paxton should have investigated the history of this particular Bike, something he concedes he knows nothing about. (Def. Mem. at 12.) According to Defendant, in spite of this lack of knowledge, Paxton assumed, for purposes of his analysis, that the Bike had a “moderate” crash history, even though he concedes that a drop of eight feet (like those regularly performed by Plaintiff) constitutes a “major episode” with respect to the frame. (Id.) Defendant further contends that Paxton should have visited the site of the accident but did not. (Id.) I do not find these arguments persuasive on the issue of the admissibility of Paxton’s Report, because Paxton’s conclusion that the Bike had defective welds is not necessarily undermined by the Bike’s history or the scene of the accident. If anything, these factors go to the weight of Paxton’s testimony, not its admissibility. Further, as noted above, Plaintiffs burden at this stage is to show that a defect in the product was a “substantial factor” in causing the accident, not that it was the “sole” cause. Even if environmental factors or the history of the Bike were found to have contributed to the failure, those elements would not automatically completely preclude a welding defect from having substantially contributed to the failure. Thus, they are not a basis for rejecting Paxton’s testimony. Defendant quotes Paxton’s testimony that a proper failure analysis would include a “quantitative assessment of the forces and loads” created by the failure event, and his concession that he never calculated such loads. (Id. at 13.) Again, I do not find this criticism to be fatal to Paxton’s testimony because his conclusion that the product was defective was based on empirical testing of the Bike itself, not on speculative calculations. Defendant claims Paxton changed his theories about the frame failure repeatedly until about two months before his report was due. (Def. Mem. at 15.) Defendant states that it confronted Paxton at his deposition with errors in his analysis of the hardness of the aluminum, and that Paxton conceded that the aluminum was within Trek’s hardness specifications. (Def. Mem. at 13-14.) Clestrly, Paxton has abandoned (since issuing his Report) his theory that the aluminum in the frame was not sufficiently hard. If he should testify to a defect in the hardness at trial, Defendant is, of course, free to cross-examine him. Paxton also conceded at his deposition that the enlarged grains he found were not near the fracture site. (Def. Mem. 14; Paxton Dep. at 196:22 — 197:1). The grain size theory does not seem to be relevant to the conclusions about the weld defect, however, and so does not provide a basis for precluding his testimony. Defendant will be free to cross-examine Paxton on any of his abandoned theories if they come up at trial. Attacking Paxton’s final conclusion that weld deposits on the interior of the aluminum frame tubing caused microscopic cracks that were a substantial factor in the frame failure, Defendant claims: (i) Paxton identified three types of cracks but did not attribute the final failure to any one of them; (ii) Paxton testified that it is “not honest” to attribute the frame failure to any one of the alleged manufacturing defects, although they had “real potential” to cause the failure; (iii). Paxton stated there is no such thing as a “perfect” weld, and that all welds have microscopic imperfections, which do “not necessarily” render a frame defective. Defendant also argues that Paxton admitted aluminum will always fail if it is,loaded with enough force— defect or no defect — and that a hypothetical perfect frame would fail first in the exact spot where this bike failed if subjected to a strong enough force. (Id.) In response, Plaintiff quotes Paxton’s Affidavit, dated January 21, 2004 (Pl.Exh. 2), specifically, portions thereof that criticize the conclusions of Defendant’s expert, Gerald P. Bretting, P.E. (professional engineer): 3. Briefly summarizing the conclusions stated in the report, my opinion is that the bicycle frame failed due to a fatigue crack which propagated through the “down tube” until the static load could not be- supported and the tube tore. In the course of the manufacturing process, excess weld metal was deposited on the interior of the tube at the weld of the “down tube” and the “head tube”. In the area of the fracture, there were several types of cracks or tears created by uncontrolled welding in the manufacturing process. While it is not possible to identify the specific crack that actually propagated, any one of these cracks could have propagated through the tube to cause the failure. Furthermore, it is probable that one of these cracks actually did .propagate to failure, because it is far, far easier for a pre-existing crack to propagate than for a new crack to be created by stresses bending a surface with no pre-existing crack. 4. I have reviewed the affidavit submitted by defense expert Gerald P. Bret-ting in support of the defendant’s motion for summary judgment. Mr. Bretting agrees that fatigue cracks existed in the area of the “head tube” — “down tube” joint ... Mr. Bretting provides no support for his assertion that these fatigue cracks were created by stresses resulting from prior hard use of the bicycle... His scenario is in fact extremely unlikely because, as stated above, it would have been far easier for one of the pre-exist-ing cracks created during the manufacturing process to propagate than for a new crack to be created by stresses bending a surface with no pre-existing crack. (PI. Mem. at 23 (quoting Paxton Aff.)) Defendant’s criticisms of Plaintiffs abandoned theories are much stronger than its criticism of his final opinion that the frame was defective because of excess weld metal deposits. First, Paxton did attribute the final failure to one of the cracks (without specifying which one), noting that it was “probable” and would have been “far easier” for one of the identified fatigue cracks to propagate than for a new crack to form. Second, the fact that Pax-ton conceded there is no such thing as a “perfect” weld does not, in and of itself, mean that this particular defective weld had the same inconsequential defects as some other welds. Clearly, Paxton opined that this weld was more defective. Defendant has failed to point out any actual error of fact or flaw in reasoning in Pax-ton’s weld conclusions, thus these criticisms are merely “forensic quibbles” that would go to the weight, and not the admissibility, of Paxton’s opinions. Byrne, supra, 2003 WL 446474 at *1 n. 1. In general, I find that Paxton’s methodology carries sufficient indicia of scientific reliability to warrant submission to a jury under Daubert and its progeny and the Federal Rules of Evidence. Most significant in this regard is Paxton’s uneontro-verted assertion that Defendant’s own metallurgical expert and defense counsel agreed upon the protocols by which Paxton analyzed the Bike’s frame. This alone indicates to the Court that Defendant’s critique of Paxton’s methodology does not render the testimony beyond the scientific pale. In addition, Paxton’s described procedures tend to indicate to the Court that he carried out a thorough and scientific analysis of the frame, and that these tests formed the basis for his conclusion that fatigue cracks caused by excess weld material were a substantial factor in causing the frame to fail. See, e.g., Byrne, supra, 2003 WL 446474 at *1 (finding sufficient indicia of reliability in expert’s background and the foundation for his opinions, despite a lack of empirical tests on the product that failed and no articulated hypothesis about the cause of failure) (internal citation omitted); see also Bruno v. Toyotomi U.S.A., Inc., 203 F.R.D. 77, 79 n. 2 (N.D.N.Y.2001) (noting that expert was qualified because he held a Ph.D. in the field, had 30-plus years of experience, had published over 100 technical papers and advised in numerous court cases). Paxton observed the actual Bike, analyzed the welds joining the head tube and down tube where the Bike failed, subjected the fracture site to magnification, and performed destructive chemical analyses. And while Defendant has pointed out several errors in Paxton’s abandoned theories, it has not discredited Paxtoji’s methods or conclusions regarding the allegedly defective weld. I also note that Paxton’s qualifications, methodology and final conclusions do not contain the flaws that ordinarily cause an expert’s opinion to be excluded. See, e.g., In re Rezulin Products Liability Litigation, 369 F.Supp.2d 398, 411-25 (S.D.N.Y.2005) (excluding expert testimony where expert relied on studies that were only tangentially relevant and ignored relevant, contradictory studies); Davidov v. Louisville Ladder Group, LLC, No. 02-Civ-6652, 2005 WL 486734 at *2 (S.D.N.Y. Mar. 1, 2005) (excluding expert report that was inconsistent with facts of case); Housing Works, Inc. v. Turner, 362 F.Supp.2d 434, 447-48 (S.D.N.Y.2005) (excluding illogical expert report that failed to address facts that would, by common sense, dictate different conclusions from those reached by the expert); Macaluso v. Herman Miller, Inc., No. Ol-Civ-11496 (JGK), 2005 WL 563169 at *6 (S.D.N.Y. Mar. 10, 2005) (excluding expert testimony where expert did not examine actual item in question and his analysis was based on incorrect factual assumptions that rendered all of his subsequent conclusions “purely speculative”); Mink Mart, Inc. v. Reliance Ins. Co., 65 F.Supp.2d 176, 181 (S.D.N.Y.1999), aff'd, 12 Fed.Appx. 23 (2d Cir.2000) (excluding expert report where it was based on speculation and not evidence that product in question malfunctioned). Having determined that Paxton may testify as an expert, I turn to the issue of whether Plaintiff has met his burden to withstand summary judgment on the manufacturing defect claim. I find that he has. 2. Elements of Manufacturing Defect Under New York law, a “manufacturer who places a defective product on the market that causes injury may be liable for the ensuing injuries. A product may be defective when it contains a manufacturing flaw.” Liriano v. Hobart Corp., 92 N.Y.2d 232, 237, 677 N.Y.S.2d 764, 700 N.E.2d 303 (1998) (“Liviano I”) (internal citation omitted). A manufacturing defect is a flaw that results from the manufacturer’s plans not being carried out correctly, usually caused by an error during the product’s manufacture or assembly. See Van Deusen v. Norton Co., 204 A.D.2d 867, 868-69, 612 N.Y.S.2d 464 (3d Dep’t 1994); Opera v. Hyva, Inc., 86 A.D.2d 373, 376-77, 450 N.Y.S.2d 615 (4th Dep’t 1982). The crux of a strict liability manufacturing defect claim is the product’s failure to perform as expected due to an error in the manufacturing process that resulted in a defect. Rainbow v. Albert Elia Bldg. Co., 79 A.D.2d 287, 294, 436 N.Y.S.2d 480 (4th Dep’t 1981); aff'd, 56 N.Y.2d 550, 449 N.Y.S.2d 967, 434 N.E.2d 1345 (1982). To recover for damages for a manufacturing defect (to recover under any strict liability theory, including failure to warn, addressed later in this opinion), a plaintiff must show that the defect was a “substantial factor” in causing his injuries. Bruno, supra, 203 F.R.D. at 78-79; Donald v. Shinn Fu Co. of Am., No. 99-Civ-6397 (ARR), 2002 WL 32068351 at *6 (E.D.N.Y. Sept. 4, 2002) (noting that plaintiff is required to show defect was the “proximate cause” of the injury) (citing Colon v. BIC USA, Inc., 199 F.Supp.2d 53, 84 (S.D.N.Y.2001)). A plaintiff asserting a strict liability claim must also show that (i) the product is not reasonably safe as marketed; (ii) the product was used for a normal purpose; (iii) that the plaintiff, by the exercise of reasonable care would not have both discovered the defect and apprehended its danger; and (iv) that the plaintiff would not have otherwise avoided the injury by the exercise of ordinary care. Urena v. Biro Manuf. Co., 114 F.3d 359, 363 (2d Cir.1997) (citing Fane v. Zimmer, Inc., 927 F.2d 124, 128 (2d Cir.1991)); see also Brazier v. Hasbro, Inc., No. 99-Civ-11258 (MBM), 2004 WL 515536 at *5 (S.D.N.Y. Mar. 16, 2004). If a defendant’s expert states that a defect in its product could not be the cause of the accident, plaintiff must rebut this assertion with admissible expert testimony. Speller v. Sears, Roebuck & Co., 100 N.Y.2d 38, 42, 760 N.Y.S.2d 79, 82, 790 N.E.2d 252, 255 (2003). Where causation is disputed, however, and plaintiff has provided “detailed, non-conclusory expert depositions and other submissions” refuting defendant’s theory, summary judgment is not appropriate. Id. at 43-44, 760 N.Y.S.2d 79, 790 N.E.2d 252 (concluding that the issue of what caused a fire was for a jury to decide, where each side’s experts had competently interpreted burn patterns differently); see also Donald, supra, 2002 WL 32068351 (denying summary judgment where genuine issue of fact existed as to whether mechanic’s failure to use jack stand was proximate cause of his injuries, and noting that accidents are rarely “mo-nocausal” and that determination of whether defect was substantial cause is usually one for a jury). In fact, for a defendant to be entitled to summary judgment on causation, it must show that plaintiffs actions were the “sole” cause of his injuries, not merely a substantial contributing factor. Donald, supra, 2002 WL 32068351 at *6; Amatulli v. Delhi Constr. Corp., 77 N.Y.2d 525, 534, 569 N.Y.S.2d 337, 571 N.E.2d 645 (1991) (denying summary judgment where defendant 'failed to show that plaintiffs conduct in diving into an above-ground pool was “sole” cause of injuries, sufficient to break chain of causation, where question of fact existed as to whether in-ground installation of above-ground pool created illusion of depth). Where plaintiff and defendant each have competent