No problems with our 37's for the last year....

Installed 40's on new rims this evening and have serious Death Wobble over 30mph. Tires/Rims were balanced this afternoon.

At first the psi varied in each tire from 22psi-30psi. Basically no two tires were the same.

Filled all the tires to 35psi and the problem is still there, seemed to be even worse.

Absolutely nothing on the JK was changed except for the tires and rims.

Any suggestions other then going back to my 37's?

 

What size rims, and what backspacing on them? Oh, and what tires? Less back spacing can cause a lot more steering wheel shimmy as the tire gets farther out from the center of the knuckle. It also increases scrub radius.

A 40" tire will weigh more, and has more leverage. So any worn components will become much more noticeable with the larger heavier tires.

 

who balanced them? chads runing the same tires and they are smooth.

40's can be a mofo to get right, of course running 40's will put a ton more stress on ball joints, Are they good?

 

Well.... tires arrived today.... ordered from 4WD

Unfortunately the stick on weights mostly fell off in transit. Had a local place remove what was left on the weights and rebalance all 5 this afternoon.

Ball joints were checked recently and had no play in them.

Tires are 40" Pro Comp Xterrains mounted on 17" Pro Comp 7005 rims

The 37" setup we were running was 37" Pro Comp Xtreme M/T's on 17" Pro Comp 7189 rims.

New rims are the same size and back spacing as the old ones.

I have another set of 40" Pro Comp tires arrving later this week on Rugged Ridge rims. Was planning on trying those out on this JK to see if the issue goes away. Obviously I was hoping to narrow down what the issue might be with these since 40's are a b!tch to swap around.

 

I would guess, its probley a balance issue, try swapping the tires around, front to back, etc

 

Even if a component was slightly worn....

Wouldnt I have noticed it somewhat running 37's? We were able to drive 80+ mph and everything was smooth. Now with the 40's we start to wobble at 25mph and by 30mpg we have to almost come to a stop to have things smooth out.

I know 40's are bigger but 37's arent exactly little guys either....

 

There is a product called Centramatic Wheel Balancers. You never have to balance your wheels again. They are a Pizza Dish looking thing that mounts behind your wheels and they balance as you drive. They have little BB's in them and once you hit 15mph they spread out and balance themselves. My buddy has 40's with beedlocks and he loves them. He has had them on his XJ before as well and hit freeway speeds with NO vibrations.

 

Checked their site and they dont appear to be made for 5 on 5 17" bolt patterns

 

You could try to get blanks and take them to a wheel shop and get them drilled? Or contact them with your issue and maybe they can do a custom drilled set. I couldn't imagine them NOT wanting to get into the JK market. All it takes is a little CNC programming on their end.

Just a thought.

Im pretty sure my buddy drilled his own after swapping these to his YJ with 8 lug pattern. if they are off in the slightest the balancers will adjust to it as soon as you start driving.

This is the rig they are on:offroad-review.com/new/index.php?page=119[/url]

 

This is a good question. Did they balance them dynamically?

My shop can only dynamically balance up to 38" tires due to the machine they use. Lack of this type of balancing is a common cause of DW.