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-   -   Would 31" tires cause "bump steer"? (http://www.wranglerforum.com/f210/would-31-tires-cause-bump-steer-3462.html)

comptech78 10-16-2006 05:46 PM

Would 31" tires cause "bump steer"?
 
I have been told by my wonderful, and all-knowing :mad: , Jeep dealership that the reason I have a "bump, shake, or vibration" in the steering wheel when I hit a bump, is due to my going from a factory size tire to a 31" size tire on my otherwise un-modified Jeep Wrangler, and thus causing things to be out of the correct setup.

Is this true? Can a wee 31" tire cause this?

I changed the tires due to the crappy Goodyears being cupped, and severe death wobble. (Must also say the dealership changed out the stabilizer, before I changed the tires.)

I now have BF Goodrich All-Terrains.

Now I have been reduced to, what I have found to be called, "bump steer".

The Jeep is a 2004, with only 39,000 miles on it. The original Death Wobble started at only 15,000 miles. I have dealt with the dealership all this time.

What is going on? Can this be fixed under warranty? Is my dealership crazy?

By the way, I am in Knoxville, TN. Any local suggestions would be welcome.

amerijeep 10-16-2006 05:57 PM

I think the dealership is full of it. I don't believe that can be you issue, but the experts here will know better than me. I don't have that TJ experience.

khenderson 10-16-2006 06:41 PM

*cough* BULL SH@! *cough*

they are so full of it. i love how dealerships tell you something just to tell you something even when they have NO clue what's happening. the only reason they'd cause it is if they weren't balanced right. but if you have already had death wobble, i'd start telling them to look at all the components in the front end to make sure everything is tight(trackbar, drag link, etc). you shouldn't have death wobble basically from the factory. something ain't right there, but they are so wrong about 31'' tires causing that.

Jerry Bransford 10-16-2006 08:29 PM

Whoever at your dealership suggested a bigger tire could cause bumpsteer should be fired. Bumpsteer is a geometry problem caused when the angle between the trackbar and drag link are no longer parallel... which is usually caused by some yahoo who installed a dropped Pitman arm on a TJ.

Bumpsteer is when the steering is forced left and right as the suspension moves up and down. So if you hit a bump or dip in the road and your Jeep has bumpsteer, the steering wheel would be jerked left or right, often violently enough to be jerked out of your hands.

Whatever it is your tires are causing, like shimmy or vibration, it's certainly not bumpsteer. Get them carefully and perfectly balanced, the problem will go away if it's truly a tire problem. :)

comptech78 10-16-2006 09:43 PM

They didn't say...
 
The dealership didn't call it "bump steer". That is what I came up with after doing a little research today after my trip to the dealership was unsuccessful. Closest thing I could come up with to the problem I have. Perhaps it is not this.

The steering wheel does not jerk out of my hands. The Jeep doesn't shake or move anything like it did with the "death wobble".

You only feel it in the steering wheel. Passengers don't even notice it.

The slight movement (shake) of the steering when going over the bumps in the road is just annoying. But the dealership just wants to blame it all on the tires making the Jeep "sit up higher" and throwing off the factory setup.

khenderson 10-16-2006 10:13 PM

Quote:

Originally Posted by comptech78
But the dealership just wants to blame it all on the tires making the Jeep "sit up higher" and throwing off the factory setup.

is that what the stealership said?!?! omg!! yes, taller tires will make the jeep sit higher, but that difference is just from the tires. it doesn't change ANYTHING about the factory suspension geometry. because you haven't lifted the body of the jeep away from the axles, nothing has changed.

wow, i wish i was still in nashville, i'd come down to that dealership with you and learn them a thing or two.
i can get fired up when stupidity/ignorance rules the situation.

redsoxjeep1 10-17-2006 12:57 PM

Quote:

Originally Posted by comptech78
I have been told by my wonderful, and all-knowing :mad: , Jeep dealership that the reason I have a "bump, shake, or vibration" in the steering wheel when I hit a bump, is due to my going from a factory size tire to a 31" size tire on my otherwise un-modified Jeep Wrangler, and thus causing things to be out of the correct setup.

Is this true? Can a wee 31" tire cause this?

I changed the tires due to the crappy Goodyears being cupped, and severe death wobble. (Must also say the dealership changed out the stabilizer, before I changed the tires.)

I now have BF Goodrich All-Terrains.

Now I have been reduced to, what I have found to be called, "bump steer".

The Jeep is a 2004, with only 39,000 miles on it. The original Death Wobble started at only 15,000 miles. I have dealt with the dealership all this time.

What is going on? Can this be fixed under warranty? Is my dealership crazy?

By the way, I am in Knoxville, TN. Any local suggestions would be welcome.


My Jeep is a STOCK 2004 and the steering shakes for a few seconds any time I hot a bump...right now there are 28 maybe 29 inch tires on the thing. Completely stock.


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