96 GTS Wheel Balance Issue

[sdaddy]

I have a vibration in the left front of my 96 GTS that begins at about 65 and gets progressively worse as speed increases. I had the front wheels balanced, and this actually seemed to make the vibration a litttle worse. I took it back and they said the wheel/tire is spot on on the spin balancer. I can't find anyone in Jacksonville who does on the car balance anymore.

The tires are evenly worn, the wheel looks okay (Forgeline) and the front steering seems to be tight. Tire does not appear to be out of round when running at high speed on the spin balancer (Michelin Pilot Sports).

What do I try next? Rotate the tire on the wheel and rebalance to see if that helps or swap the tires on the front wheels to see if the vibration stays with the tire or moves with the wheel?

Tire place wants to know if I want to try weights on the inside and outside of wheel, but I have never seen this done on a Forgeline. I hate to spend $600 on new tires to remove this variable, as the Pilot Sports are under 5 years old and have over 50% tread.

I bought the tire and wheels used and the tire wear was on another 96 GTS, but the tire wear is dead even. I had a little left side vibration with the original tires/wheels but nothing that kept me from running 120 at the strip.

I was headed to the strip yesterday, but when I got the car up to about 80 I said "no way". I also just added poly engine and transmission mounts. Would this magnify a front end vibration issue? The vibration does not go away at speed if you push in the clutch.

Any suggestions?

 

[sdaddy]

I went ahead and had them swap the front tires left to right, kept the wheels where they were and rebalanced to see if the vibration moved left to right.. Still a vibration on the left side. No sign of damage or repair on either wheel. The tire guy said the left front Forgeline had a "runout" of 12, but they ususally saw that at 20 before it caused vibration issues. Tires show perfectly even wear.

What else do I need to be looking at? Brake rotor? Shocks?

 

[plumcrazy]

call tator.....

 

[Solid Red 98]

Examine the "runout" again, as it might be a bent wheel that is hard to see. I'm thinking inner bead area. A timed mechanical vibration on the front implies a high or low spot on one or both wheels. My 2cents. Good luck with it.

 

[uvbnbit]

.012" is well within OEM spec. Personally, I don't think you can feel an out-of-round issue until .040"+
Check ball joints? bearings?

 

[mjorgensen Woodhouse]

Were the wheels made for your year Viper and hub centric? We have seen some wheels that will not balance well on the hub hole and there are new ways using the actual lug holes to balance. We have had good luck, but the process is not much fun.

When the wheel is mounted does the run out or the tire itself show any wobble?

 

[uvbnbit]

+1
Does the right side have a hub-centric ring on it?
I've seen shops "forget" to put those back on, causing slight vibration issues.

 

[sdaddy]

It does have the concentric ring on the both sides. I talked to Chuck Tator and he suggested I try swapping the rotors to eliminate that as a possibility. Rotors look rusty on the edges but show no damage. I got the two main bolts off the first calipers and stripped the bolt that holds the brake line. Doesn't that just figure? Waiting now on Craftsman stripped bolt sockets. I had to put it all back together and pull it back in the garage as I am the HOA President and Treasurer and did not want to leave the car on jack stands in the driveway. Actually, working on the car in the driveway is already a "no no". I am not too worried since I don't plan to send myself a letter.

I was surprised that it appears that all that holds on the rotor is the wheel lugs (after you get the caliper off). I am now wondering if just some minor rust behind the rotor might be keeping the rotor from sitting completely flat on the hub and causing vibration at speed.

 

[Chuck 98 RT/10]

I would have swapped both wheels with another Viper first. If the problem persists with completely different wheels then you know it's the suspension.

How many miles on the car?

 

[uvbnbit]

Have you checked the "run out" on the hubs(at the lug bolts)?
allowed runout is typically 0.005 inch (0.127mm)

 

[sdaddy]

I would have swapped both wheels with another Viper first. If the problem persists with completely different wheels then you know it's the suspension.

How many miles on the car?

I had a slight vibration in the left front with the factory wheels, but not as bad as when I put these on. Car just rolled over 21,000 miles today.

 

[sdaddy]

Have you checked the "run out" on the hubs(at the lug bolts)?
allowed runout is typically 0.005 inch (0.127mm)

Not sure how to do this. Chuck Tator said to try swapping the rotor and I am working on that. I asked him if he thought it could be the hub and he said he doubted it. Shock shows no sign of any leakage.

 

[Jack B]

I don't know if I missed it, but, the Hunter 9700 does a road-force balance. A spin balance does not cut it. Hunter has a list of sites that have the 9700.

 

[sdaddy]

I don't know if I missed it, but, the Hunter 9700 does a road-force balance. A spin balance does not cut it. Hunter has a list of sites that have the 9700.

The shop I used has a road force balancer that puts 1200 pounds of road force on the tire. I think it is a Hunter, but not sure of the model number. They are not listed as having a 9700, but another one of their locations about 7 miles further down the road has one. I will give that a shot if I cannot find any other vibration source.

M. Jorgensen at Woodhouse said they have had some trouble balancing aftermarket wheels where the balancer only uses the hole in the wheel center. He said they have one that uses the six lug bolt holes and it seems to work better. I have never seen one like that.

 

[SoCal Rebell]

What else do I need to be looking at?

Look for ******** far rightwing Republicans in your neighborhood

.

 

[DFW GTS]

It is very likely that the left hub is damaged and has too much runout. When I purchased my car both front hubs had that problem.

Another symptom of this problem is the brake pedal getting soft as you drive due to pad knock back.

 

[DFW GTS]

Not sure how to do this. Chuck Tator said to try swapping the rotor and I am working on that. I asked him if he thought it could be the hub and he said he doubted it. Shock shows no sign of any leakage.

To check the front hub runout:

1. Jack the car up and support it.

2. Remove the wheel.

3. Reinstall the lugnuts with the shoulder turned backwards to hold the rotor onto the hub.

5. Mount a dial indicator (using a magnetic base stand) to the spindle with the needle riding on the outside edge of the rotor.

6. Spin the hub to check runout.

 

[sdaddy]

To check the front hub runout:

1. Jack the car up and support it.

2. Remove the wheel.

3. Reinstall the lugnuts with the shoulder turned backwards to hold the rotor onto the hub.

5. Mount a dial indicator (using a magnetic base stand) to the spindle with the needle riding on the outside edge of the rotor.

6. Spin the hub to check runout.

Thanks for the "how to" on checking front hub runout.

 

[sdaddy]

Look for ******** far rightwing Republicans in your neighborhood

.

LOL

They could be removing or adding weights when the car sits in my driveway! I like a good conspiracy theory.

 

[uvbnbit]

To check the front hub runout:

1. Jack the car up and support it.

2. Remove the wheel.

3. Reinstall the lugnuts with the shoulder turned backwards to hold the rotor onto the hub.

5. Mount a dial indicator (using a magnetic base stand) to the spindle with the needle riding on the outside edge of the rotor.

6. Spin the hub to check runout.

Can also check on the lug studs. Should be less than .005" difference between the "lowest" and "highest".

 

[Tom Sessions]

You may want to check the hubnut also. You cant remove the nut but you can tighten it. This can give you a idea of wear on the hub. Torque it to 250-300 lbs/ft. It will surprise you how much you will turn the nut.

 

[sdaddy]

You may want to check the hubnut also. You cant remove the nut but you can tighten it. This can give you a idea of wear on the hub. Torque it to 250-300 lbs/ft. It will surprise you how much you will turn the nut.

I have heard this takes three guys and an eight foot breaker bar extension! LOL

 

[GTS Dean]

I have heard this takes three guys and an eight foot breaker bar extension! LOL

It takes one 200# man standing on the end of an 18" breaker bar.