Ride quality and type of pavement?

Hello Doc,

Some kind of resonance at the "sweet spot" speed range generated by the combination of the new road surface (not fully finished, as in needs more steam rolling), the tires (as in tread design and pressure), suspension and frame of the vehicle whereby the combination of all of the above causes the tire/road contact area to be reduced enough to affect drivability? (Slightly similar to a vehicle hitting the rumble strips on the shoulders of a highway?) Gee, I don't know -- just drive at 70 mph, Doc...

Regards, Franko

""Doc""

i've had the same problem in the past. the only causes i found for it was mud in the rims or the the road repair was slightly uneven. caused by the guy on the roller not packing the surface right. as time goes on and cars smoth out the new spots you will find that it goes away.

I guess that it could be the new road condition as S.S.I.N. stated in his post. Especially if on any other smooth surface you don't feel it. My 99' K1500 would act this way on some road surfaces that were generally smooth. Boggles the mind as you would think that all would be good on a smooth road, but I saw similar issues as you are. I recently replaced the factory Good-Year tires with a set of Yokohama Geolanders not because of the ride but it did need tires. I don't notice the shimmy now hardly at all. I do know that in some radial tires there is shifting of the belts as the tires are used. I'm attributing my shimmy issue to that.

Brian

P.S. I think that why you don't feel this same phenomena on a passenger car is due to the truck being so light in the rear end.

My 2 cents.

Brian

Try removing the tire and wheel assembly:

Roll it and listen for noise on the inside. If you hear any noise at all. it's the talc and rubber balled up which gathers into a mass at the speed you mention.

Are you using a good computer balancer? Sometimes a bubble balancer will show this, where a computer balancer won't, as a lack of repeatability.

Refinish King

rotate the tires and see if the problem moves Mike

I would try rebalancing the tires on a Hunter load force balancer - Discount Tire has them (i think each store has only one, they only use it if you specifically ask for it) as do most Cadillac/Buick dealerships.

What makes this machine so special? Does it cost any extra to have your tires balanced on it?

The machine has a Roller in the back, when you set the Machine to do a Road Force Balance, while the machine spins the tire, this roller will push down on the tire with a lot of force and simulate the tire driving down the road. It can then measure if there's something wrong with either the tire or the wheel. This is something most Balancing machines out there CAN'T DO! You can balance a tire perfect, and the tire or wheel can still be screwed up. It also will do a better Balancing job. Especially if you want to do a Dynamic Balance and have No weights on the outside. Usually you'll end up with a Static Balance, but on the Hunter it's easy to do a Dynamic and have both sets of weights on the inside. Nice when you have some 20's 22's, or well whatever nice Aluminum wheel you happen to have.

You can when road forcing have the Machine tell you where to have the tire located on the wheel to get a lower Roadforce reading. Sometimes it'll make a huge difference. Other times, the Tire is just BAD and needs to be replaced.

You can then get your Results Pr>> I would try rebalancing the tires on a Hunter load force balancer -

Inline...................

Did that to check for mud inside the rims...................

Yeah I did that too, no noise!

The shop I take it to uses a computer balancer, dunno if it's a good one or not.

Doc

Off to discount tire I go, hi ho hi ho hi ho.................................

Doc

Already did that, no change.

Doc

Model #975.

Refinish King

PS Make sure the bearings are good. They only last approximately 100 tires.

It puts up to 1500 lbs of force on the tread.

Refinish King

Not to mention:

It can give you up to 12 configurations of mounting, to eliminate tire induced pull phenomenon.

Refinish King

Hi Doc. I had a truck once that I had to have one of the wheels balanced while installed on the truck.The guy up the street has a machine that does this somehow,and since he was the only guy in town that would mess with split-rims I let him handle all my tire issues. If the hub/drum is out of balance you will never get a perfect blance by balancing the wheel/tire alone. I would try putting some weight back there to see if that changed things,and if so maybe replace the shocks.Also if she's driving empty maybe the tire pressure is too high for that condition causing a bounce. It's definately not drive shaft vibration right? Best ....Brian O.

Doc,

Just a thought, maybe your shocks are the culprit?

Brian

I wish, shocks are fine.

Doc

Brian,

Have 500 lbs back there right now for snow season and not a change. Have also tried different tire pressures unloaded and loaded to no avail.

Might be a drum out of whack....................pretty sure it's not driveshaft vibration. U-joints are fine, but I'd have to drive quite some distance to have the driveshaft balanced so it be the shaft itself is out of whack.

Doc