Tire bouncing like a pogo stick!

[Ghost]

So I noticed on my son's 98 xj the other day one tire bouncing like a pogo stick up and down. We had the shop that sold us the tires check them and they all balance fine. I shifted the tire to the front and it appears to be fine there. So it seems like it's the Driver side rear only. Suggestions on what to replace to fix it? Starts at about 50 or 55. 235/75/16 Cooper AT3's if that matters.

 

[old_man]

First off, if it is bouncing that much, I would check my shocks.

A tire can balance fine, but be out of round.

 

[Tim_MN]

Have the tires balanced on a Hunter Road Force tire balance machine, and as already suggested, consider that new shocks might be needed.

 

[md21722]

Check the shocks.

 

[Ghost]

I looked at some things Monday after he returned from the tire shop and looks like the rear up country springs are flat too. I would assume just pulling the shock should tell me what I need to know.

 

[Digger87xj]

As others have said, a bad shock will let the tire hop.

 

[Overland]

With Cooper tires, I'd look them all over closely for bumps in the tread. Seen them start coming apart after very few miles, wouldn't let a friend buy Coopers.

 

[Digger87xj]

heh. Love my coops.

 

[Overland]

Sure, they don't all come apart, but my experience has led me to put faith in other manufacturers.

Tire bouncing like a pogo stick + Cooper tires = probably a tire problem.

 

[Tim_MN]

Tire bouncing like a pogo stick + Cooper tires = probably a tire problem.

Once the shocks are proven to be good, one might suspect a bad tire, with any brand name.

 

[shelbyluvv]

I have Coopers on all 4 of my vehicles. Never a problem out of them.

 

[Ghost]

With Cooper tires, I'd look them all over closely for bumps in the tread. Seen them start coming apart after very few miles, wouldn't let a friend buy Coopers.

Bumps in the groves or just all over?

heh. Love my coops.

x2!

I have Coopers on all 4 of my vehicles. Never a problem out of them.

We have run Cooper's on our Commercial trucks over the road for years. On my personal company truck for years and on my Jeeps. I really like Cooper tires and have never had an issue with them.

I put new shocks on this vehicle when I bought it about a year or more ago. Right now I'm in Crawl Crunch mode to get my jeep ready so hopefully I can find time this weekend to look it over.

 

[BCKNBLK]

Just one more guy saying its the shock absorber.

 

[Overland]

A bump in a tire would be where the tread has separated from the carcass. It'll appear as part of the tread area is "a little rounder" than the rest of the tire. Last time I had one pop up, I thought it was on the front, as the wheel was shaking. Front tires looked fine. Pulled over again, looked again at the front, fine, but saw the bump on the back getting back in the truck. One tire out of that set blew out in the driveway, cold, and parked.

I harp on Peerless, Cooper, and Firestone all the same. Pro Comp has recently been added to that list. Some tires I just won't accept for free.

If you jack up each corner so it's just off the floor enough to spin, you'll notice a tire out of round pretty quick, as the high spot will catch.

 

[JeepNoob]

Have to agree with the possibility of a bulge in the tire. Had an old Chevy CUCV that went through two pairs of crappy, old tires in the rear driver's side before I got new ones put on. It was just twisting the belts up internally and causing a nice little bulge. It also seemed to be most noticeable at the speeds you mentioned (50 or 55.) Quick, easy, dirty check is to just jack up the suspect tire and run your palm along the tread without turning the tire too much. If it's bulged, you'll feel it. Secondary method is to take it into a tire shop and tell them you want them to measure the radial runout on the tire(s). They should know what you're talking about. This involves checking for high/low spots on the tire tread with a dial indicator and is usually accurate down to thousandths of an inch.

 

[Tryfan]

Have you checked to see if the tire might be cupped. Cupping on deep tread tires can give the appearance of bouncing up and down especially if shocks are bad