test drive on freeway: car didn't pull, but...

[heftylefty58]

Well, I've fallen in love with Yukons, so I'm in the process of shopping around for a used one.

I test drove an absolute beauty that had 20' BBS wheels with 295/50R20 tires. Unfortunately, once we got to ~50 or 60 mph, the car seemed to sway left and right. I've never quite experienced this before, but it definitely felt unsafe. I'm guessing the car didn't necessarily have an alignment problem because it didn't really pull left or right. (It swayed left and right in roughly equal amounts.)

Just curious if any of you have insight regarding the Yukon's swaying behavior at freeway speeds. (For eg, is it common, what causes it, is this expected behavior with these tire dimensions, could this be an expensive fix, can it even be fixed at all, should I no longer consider buying this car, would it be worth it for me to have the owner take it in for a used car inspection, etc).

Thanks in advance.

[2000CAYukon]

Caster is the angle from the upper ball joint to the lower ball joint. Negative caster can cause swaying at higher speeds. My guess is that the 20s have caused the caster to change and perhaps the alignment was not done right or they could not correct for the negative caster.

If you are serious about the Yukon, have the alignment checked to see what the specs are and if it can be corrected.

//2000CAYukon

[heftylefty58]

Thanks bud--I'm having a mechanic check it out at this very moment. I hope he finds the cause/fix!

Thanks again.

[envoyxuv]

i've driven a pretty fair share of yukons, and have also observed the conditions you are describing. The only time i have observed this is when the vehicle had oversized (20 inch+) wheels. They seem really squirrely at higher speeds, and feel like they lack stability, as you have described.

[heftylefty58]

In case anyone didn't know, this phenomenon is apparently called tramlining.