Mechanics Expert Was Not Allowed to Opine on the Casting Defect in the Knuckle

This action arises from a single-vehicle rollover incident in which Plaintiffs suffered bodily injuries. On March 3, 2020, James Dozier purchased a new Kawasaki Teryx, an offroad utility vehicle commonly referred to as a “side-by-side.” Dozier purchased the side-by-side for the use of his three children, M.L.D., B.S.D., and C.D.

On February 21, 2021, M.L.D. was driving the side-by-side on paved roads near Gray; B.S.D. was in the passenger seat, and the children’s cousin, Ms. Blankenship, was in the back seat. M.L.D. was fourteen years old; B.S.D. was twelve; and Ms. Blankenship was seventeen.

Ahead of M.L.D., the children’s mother was driving a different side-by-side, and C.D. was riding a dirt bike. Shortly after M.L.D. turned onto Route 233 from a smaller road, she felt the side-by-side “steering to the right,” and “after that, [the side-by-side] just flipped.” M.L.D. testified in her deposition that she believed, apparently based on what she had been told by adults, that the crash occurred because “something” on the side-by-side “broke.”

Plaintiffs estimated that the side-by-side was traveling at around twenty-five to thirty miles per hour when it rolled over. The side-by-side came to rest upside down, and Plaintiffs, who were all wearing seatbelts, remained suspended inside the vehicle. Plaintiffs suffered various injuries in the rollover, including bumps, bruises, cuts, a fractured humerus (suffered by B.S.D.), and a concussion (suffered by Ms. Blankenship).

Plaintiffs and Kawasaki agreed that post-rollover inspections of the side-by-side revealed significant damage to several components of the rear-left wheel assembly of the side-by-side, including the knuckle, the bearing assembly, and the wheel itself. The parties disagreed, however, about the cause of that damage.

Kawasaki argued that the damage to the rear-left wheel assembly was caused by Plaintiffs’ misuse of the side-by-side and/or by the rollover itself. Kawasaki further argued that the report and testimony of Plaintiffs’ proposed manufacturing-defect expert, Christopher Walters, should be excluded because Walters is not qualified and his opinions are not reliable.

Defendant Kawasaki Motors Corp., U.S.A. filed a motion to exclude the testimony of Walters as well as a motion to exclude the affidavit of Walters.

Mechanics Expert Witness

Christopher Walters has nearly 18 years of hands on mechanical experience, both as a UTV dealer employee and as a sole owner of his own garage, maintaining and repairing hundreds of UTVs, including repairs personally performed on UTVs damaged by rough trail riding and roll-over events.

Get the full story on challenges to Christopher Walters ' expert opinions and testimony with an in-depth Challenge Study.

Discussion by the Court

A. Motion to Exclude Affidavit

Plaintiffs relied heavily on the affidavit completed by Walters on September 25, 2025. Kawasaki sought to exclude Walters’ affidavit as untimely and otherwise inadmissible under the Federal Rules of Evidence and the sham-affidavit doctrine.

The Court noted that because Plaintiffs did not respond to the Motion to Exclude Affidavit, the Court considered the motion to be unopposed. That alone is a sufficient reason to grant the motion and exclude the affidavit.

Moreover, the affidavit is clearly untimely. On January 12, 2024, the Court entered a Scheduling Order requiring the Plaintiffs to disclose the identity of their expert witnesses and any reports or summaries required by Rule 26(a)(2) no later than January 17, 2025. The Court later extended the expert-discovery deadline to August 18, 2025.

The content of Walters’ affidavit—which was completed well after the deadline for expert discovery had passed and after Kawasaki had filed its motion to exclude his report and testimony—goes beyond that of his initial report and deposition.

Put simply, Walters’ affidavit references information and introduces opinions that were not offered or identified in his initial report or deposition. Here, Walters’ affidavit is an untimely attempt to introduce new information gathered well after the deadline for expert discovery. It is not a proper supplement under Rule 26(e).

Accordingly, the Court will exercise its “broad discretion” to exclude Walters’ untimely affidavit.

B. Motion to Exclude Expert Testimony

The Court first noted that the report and testimony are excludable based solely on Plaintiffs’ failure to comply with Rule 26(a)(2)(B).

Here, Walters was retained by Plaintiffs to provide expert testimony, so he was required to complete a written report in compliance with Rule 26(a)(2)(B). For that purpose, Walters’ report was plainly deficient. The “report” consists of a single paragraph and contains little more than Mr. Walters’s conclusory opinions. The report suggests that Walters performed some kind of “inspection,” but it does not include any information about what that inspection entailed. It does not, for example, indicate whether the inspection was merely visual or whether it included any kind of testing, and it does not indicate which components of the side-by-side Walters “inspected.” In other words, the report offers essentially no information about the “facts or data” that Walters relied upon to form his opinions. Moreover, the report gestures vaguely toward the reasoning that Walters used to develop his opinions, but it falls well short of providing “a line of reasoning arising from a logical foundation,” as required by Rule 26(a)(2)(i).

Kawasaki also argued that Walters’ opinions are not reliable because he (1) “failed to provide any basis to find that his methods of visually inspecting the [side-by-side] to determine the existence of a manufacturing defect in the casting of the rear knuckle ha[ve] been tested, accepted, or used by other experts in the field of mechanical engineering, metallurgy, or accident reconstruction,” and (2) “identified no specific defect [in the knuckle] . . . and failed to eliminate or meaningfully consider several obvious alternatives (e.g. damage occurring during the rollover or due to impact).”

Kawasaki correctly argued that Walters had no basis to reliably conclude that there was any kind of particular defect, including a casting defect, in the rear-left knuckle. To reliably form that kind of opinion, Walters likely would have needed to employ some of the metallurgical methods referenced in Kawasaki’s briefs: “laboratory testing, microscopy, measurements, calculations, or exemplar testing.”

At the very least, Walters would have needed to identify some affirmative evidence in support of his theory, and he admitted in his deposition that he did not observe any evidence of either a bad casting or a hairline fracture consistent with a manufacturing defect and that his opinion was ultimately based on little more than his own “belief.” Thus, Walters’ opinion that there was a casting defect in the knuckle is plainly unreliable.

Walters’ “initial report” was plainly inadequate under Rule 26(a)(2)(B), and his report and testimony could be excluded on that ground alone. Moreover, Walters provided almost no explanation for his opinion that there was a casting defect in the knuckle, and the explanation he did provide indicated that his opinion was ultimately based on no more than his subjective beliefs. The Court, in its role as evidentiary gatekeeper under Rule 702, therefore granted Kawasaki’s motion to exclude expert testimony.

Held

• The Court granted Defendant Kawasaki Motors Corp., U.S.A.'s motion to exclude the affidavit of Chris Walters.

• The Court granted Defendant's motion to exclude the testimony of Plaintiffs' expert, Chris Walters.

Key Takeaway

The concept of "reliability" implies that an expert's opinion must be based on something "more than subjective belief or unsupported speculation."

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