Tech Area

Bumpsteer

Question: Prior to having an 86' Fiero GT, I've seen on the Fiero Shop in CA. offer a new 88' conversion to mount on to the '84-87 fieros. So does Held motorsports have the same prospect to elimiate "bumpsteer". Still have no idea what bumpsteer is? I've read this on both of these web sites about the bumpsteer improvement. Have you ever tried this conversion on someone's or your Fiero? Is it to have a close copy of the 1988's Fiero handling? Or just elimiate bumpsteer? What is bumpsteer???

Answer: "Bumpsteer" is created by a wheel changing toe-in or toe-out as it moves up and down. In effect, causing that wheel to have a steering effect. '84-87 Fiero's have this aggrevated on the rear by the toe adjusting rod being mounted much higher then the spindles pivot point at the lower ball joint. A matter of geometry.

Various fixes attempt to move the adjusting rod more closely in line (or shorten it's travel) to the spindles pivot point. We have not used any of the kits, but the stock geometry is adequate for ordinary driving. Spirited, and especially competition driving, is a different story. You don't need a single wheel to (bump) steer in or out just because the suspension hits a "bump" or has the cars weight "loaded" toward one side. The '88 suspension uses links to locate the spindles pivot point and adjust the toe that are virtually in a straight line. That allows the suspension to go up and down without "turning" the wheel.

This is the short course. The long course takes several years of geometry, and we didn't take geometry!!!

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