My 99 4runner has lots of vibration, almost thumping, when I brake moderately (going downhill, etc..). I took it into the shop and they said the brakes are fine - almost new. The only problem he found was my right rear tire was way out of round. So questions:

1. What's causing the vibration/thumping I feel in the steering wheel? can't be a rear tire, right?


2. The tire that's out of round is only 6 months old. Do I have to scrap it? What problems could I encounter if I don't change it out? (And what exactly is "out of round"? - is the rubber giving in one area?)

OK, more than two questions...


thanks!

Kurt

 

Here is something to explain various tire balance problems:
http://www.gsp9700.com/pub/features/intro.cfm

 

Thanks for the link. What's a road force balance?
Kurt

 

I agree the thumbing while braking is probably because your rotors are warped (while your brake pads are fine). It happened to several 3rd gen owners on this board, me included. I replaced my front rotors with brembo rotors and it removed the problem. Don't get the old rotors turned, new OEM are only a little more and will last longer.

 

My understanding of this is when they balance the tire simulating what it would be like on the road. I've also heard this as "high speed balancing." This is a more true balancing but costs a ton more. An average balance is $7 while this is $25 per tire.

 

What about vibrations at high speeds (60-70 mph) in the steering wheel? That's another symptom....

Should I just scrap these tires?? (Goodyear Wrangler RT/S)

New rotors and new tires?

 

That sounds like balancing issue. The wheels are lug centric so make sure the place you get them balanced at has the proper adaptor (do a search for adaptor I think it is called Haweka) or go to a Toyota mechanic/dealer. Do you have any warranty on the tires?

 

I assume the 3rd Gen has a wimpy steering stabilizer shock... the 2nd Gens have really a really wimpy stock part. If that's bad, you'll have vibrations when you brake and when you don't.

However, just adding a stiffer shock to cover up the vibrations caused by bad rotors or balancing would not be a good idea.

 

I don't think the 3rd gen has a steering stabilizer
https://www.yotatech.com/forums/show...ilizer+3rd+gen

 

If your tires are indeed balanced, then have your alignment checked. Excessive toe-in might be causing the tires to shimmy which you would feel in the steering wheel.

 

Good call, I was taking a guess... haven't played around with a 3rd Gen. that much.

(contrary to my previous post,)

so yah! Slap a stabilizer on there anyway, that will cover up all the shimmy

 

thanks for the input -I think I'm gonna take it to our Toy mech. and let them diagnose if it's balancing or alignment (or rotors) or what...not looking fwd to that bill, though.

thanks,
Kurt