Wheel Question Again... the saga continues

[Franke]

Do you have someone nearby that could lend you their wheels for a run down the road to eliminate the possibility of tire/wheels.

[GOLDCYLON]

Originally Posted by Franke

Do you have someone nearby that could lend you their wheels for a run down the road to eliminate the possibility of tire/wheels.

Great idea

[Dynomite]

Originally Posted by Franke

Do you have someone nearby that could lend you their wheels for a run down the road to eliminate the possibility of tire/wheels.

That will work like Daryll said

[Racinfan83]

Wish I did...

[Vette Guy]

I chased down a vibration for a long time.... Rims, tires, bearings, u-joints.... Switching out the driveshaft and yoke made all the difference. I intend to have my original drive shaft and yoke balanced, and anticipate they will be able to tell me how much off it was. My vibration was bad around 68ish, above or below, it wasn't too bad... Eliminate one variable at a time if you can. Good luck.

Mark

[Racinfan83]

Originally Posted by Vette Guy

I chased down a vibration for a long time.... Rims, tires, bearings, u-joints.... Switching out the driveshaft and yoke made all the difference. I intend to have my original drive shaft and yoke balanced, and anticipate they will be able to tell me how much off it was. My vibration was bad around 68ish, above or below, it wasn't too bad... Eliminate one variable at a time if you can. Good luck.

Mark

Yeah this vibration is at any speed above like 50. Below 50 you just can't tell it. It is not a harmonic vibration like I have had with bad u-joints in other vehicles. Checked the half shaft u-joints they are tight. Will check hub bearings today. Rotors aren't warped - stops smooth as silk when braking. (Had my share of those on other vehicles too) I'm not blessed with a plethora of ZR-1 friends here in this area that I could go swap wheels with unfortunately. Wish I was closer to the Chicago gang but that is over 5 hours away....

[WVZR-1]

Knowing what you've been through and have done chasing the issue I'd think your only reasonable diagnostic tool would be to do a ride along with someone or drive along and if you find a car that "suites you" (not meant in sarcasm) at speed, you then take those tires and wheels to your car and see if your car still has the same issues or not. There is no other economical or feasible way to accomplish it.

It would easily be worth a couple hundred mile drive to evaluate another car. You mention before hand the speeds that are your concern or where it's most notable. Have that person pass on to you that his car passes the test he feels and you then do the drive.

If his to yours passes the test you move yours to his car and see if the same scenario plays out on his car. Two tire swaps and the diagnostics are done.

I would think I'd be interested in doing this with someone that has recent tires and maybe stock wheels or if the wheels are aftermarket that their "hub-centric" because there's a few less hassles although as it's been mentioned there's nothing wrong with "lug-centric" and regardless of the center-bore Corvettes are actually "lug-centric" although it's done on wheels that are very close to "hub-centric"!

A good day of driving, lunch or whatever and it's done/over - no more diagnostics.

If you only wanted to do the swap one way from a car to yours you wouldn't need a ZR-1, just a C4 with newer tires, stock wheels and "no issues"!

[batchman]

With no other candidates (c4, c5, 80s/90s camaro/firebird/bmw/others?) to swap a pair of tires (might as well do one end at a time) you could just put your donut spare on one corner at a time. Pain in the butt but will narrow down to which tire or is it the car. So if you move the spare to all four corners and still have the vibe, it's the car.

I get *maybe* 200 miles out of a hub. *Any* hub. It's not the mileage, it's the history.
Forget hub centric, if your lugs are correct and torqued correctly they hold the wheel through much more abuse (see 200 miles on a hub if I'm lucky) and my competition wheels are lug centric only.

Have you had an alignment, did the tech notice one corner needing or having a lot of adjustment range taken up?

You could have more than one bent wheel, in either or both sets too!

HTH,
- Jeff

[A26B]

Originally Posted by Vette Guy

I chased down a vibration for a long time.... Rims, tires, bearings, u-joints.... Switching out the driveshaft and yoke made all the difference. I intend to have my original drive shaft and yoke balanced, and anticipate they will be able to tell me how much off it was. My vibration was bad around 68ish, above or below, it wasn't too bad... Eliminate one variable at a time if you can. Good luck.

Mark

I agree with this possibility..... driveshaft may have been removed and re-installed out of phase, meaning it was not installed in the same position on the differential yoke just as it was removed. This has happened before.

May also be a worn front yoke or worn tail bearing/bushing allowing the yoke to oscillate. Over-tightened front C-beam bolts can cause the bearing/bushing to incur accelerated wear.

Suggest:
1. Check with the previous owner to see if the driveshaft has been removed, or
2. Use 2 post lift, in neutral, turn the tires & check driveshaft run-out near both front & rear u-joints and in the middle.
3. check for excessive movement of front yoke. If noted, will require removal to determine if yoke, bearing/bushing or both are a fault. If the yoke is to be replaced, contact Bill Boudreau at www.ZFDoc.com. The correct Spicer yoke can be difficult to find. Bill can tell you the difference from a commonly available yoke which is not quite right.

From Bill (ZFDoc) Boudreau;

Just to warn you up front, finding a suitable slip yolk replacement will be extremely difficult since SPICER discontinued production of the 2-3-13131X slip yolk assembly. There is no shortage of replacement slip yolk assemblies that claim to be exact replacement units of the original SPICER unit, but what they don’t tell you is that in new form, these knock-offs have the same excessive spline play equivalent to an original 2-3-13131X slip yolk with 100K miles spline stretch on it.

None of the above checks will be difficult or expensive and may help to eliminate a distinct possibility. Looks like you have been through the wheel/tire possibility pretty thoroughly.

Good luck.

[Racinfan83]

Well - haven't driven it yet - but I took wheels off again and applied a strip of the airplane aluminum tape around the inside of the wheel bores. Stuff was only a couple thousandths off if that when I measured the inside after tape vs the hub. Hopefully...
Pulled on the rears at 12/6 and 3/9. There is maybe 1/16" movement in both at the outer edge. Good, bad, can be tightened with the nut???
Spun the fronts and tried to look across the top of the tire aligning with a washer edge on the inner fender. They look to be pretty round - just the slightest hint of difference. Once again thats the eyeball method which is what I have.. They do not appear to have any sideways runout at all.

On the driveshaft deal - would that cause a steady vibration or a harmonic one? This is steady. Does it even if I put in in neutral and let it roll. I understand the shaft is still turning but the pressure is off it. I and the mechanic checked it when it was on the lift and could not find anything even remotely loose. Can't find the PO - the guy I got it from got it at auction and didn't do anything to it other then let it sit in his garage.

Alignment is a possibility - haven't gotten with the local guy here to get it on the rack yet. Measured with a tape and boards like we do on the circle track car and appears to be close - although I know that is the "redneck method"..
Will drive it tomorrow to a show - see what it does then. I have to get ready for dirt racin tonite...

If this stuff don't work maybe I just need to suck it up and make a 5 hr trip up to see the FBI gang and swap wheels with one of them...
Thanks all and will let you know..