Bad Vibration under acceleration

[biggsy]

Hello,

I am hoping I can get some suggestions on a bad vibration I am having. During my last event, everything was solid the first 2 sessions. The third one was good but I did have small vibrations. In the last session of the day at mid corner and acceleration I would feel the right side of the car vibrate. I don’t feel it in the steering wheel.

When I came home I put the right side in the air and checked the front and rear tire for any play to rule out bearings. I’m happy I remembered to mark my tires when I got them mounted to check for wheel slip. You can see in the pictures that there was a decent amount of slip(about 3inches or so) from the silver line on tire to valve stem. I am thinking the wheel is now unbalanced but I don’t know how much slip could unbalance a wheel.

I have came across a thread on another forum that bad diff bushings can cause bad vibrations but I don’t hear anything abnormal when shifting or going over speed bumps.

I have an appointment this Friday with the shop to rebalance the wheels and hopefully solve that.
Is there anything I’m missing to check?

 

[bnight]

When I came home I put the right side in the air and checked the front and rear tire for any play to rule out bearings. I’m happy I remembered to mark my tires when I got them mounted to check for wheel slip. You can see in the pictures that there was a decent amount of slip(about 3inches or so) from the silver line on tire to valve stem. I am thinking the wheel is now unbalanced but I don’t know how much slip could unbalance a wheel.

Your tires are unbalanced now. I suggest you balance them and then see if you have some other issue. My car on my race tires after the track was underivable got home switched to street tires everything was fine in the world. I hope I didn't bent a wheel though. Need to find time to get them to the shop as I need to rotate them anyway.

 

[biggsy]

Your tires are unbalanced now. I suggest you balance them and then see if you have some other issue. My car on my race tires after the track was underivable got home switched to street tires everything was fine in the world. I hope I didn't bent a wheel though. Need to find time to get them to the shop as I need to rotate them anyway.

This is the first year I’m running staggered offsets. How often do you switch yours side to side? (Unless you’re using a directional tire)

 

[bnight]

This is the first year I’m running staggered offsets. How often do you switch yours side to side? (Unless you’re using a directional tire)

I'm on square tires and directional tires but I usually switch front to back than side to side however don't know why but this time my left side tires are looking much better than my left side tires so I only need to rotate front right to rear left and will have a fresh set of fronts and used rears. Ones the rears wear out I buy 2 new tires and put on fronts and the old fronts are moved to the back and the cycle continue.

 

[EF1]

Hello,

I am hoping I can get some suggestions on a bad vibration I am having. During my last event, everything was solid the first 2 sessions. The third one was good but I did have small vibrations. In the last session of the day at mid corner and acceleration I would feel the right side of the car vibrate. I don’t feel it in the steering wheel.

When I came home I put the right side in the air and checked the front and rear tire for any play to rule out bearings. I’m happy I remembered to mark my tires when I got them mounted to check for wheel slip. You can see in the pictures that there was a decent amount of slip(about 3inches or so) from the silver line on tire to valve stem. I am thinking the wheel is now unbalanced but I don’t know how much slip could unbalance a wheel.

I have came across a thread on another forum that bad diff bushings can cause bad vibrations but I don’t hear anything abnormal when shifting or going over speed bumps.

I have an appointment this Friday with the shop to rebalance the wheels and hopefully solve that.
Is there anything I’m missing to check?

Sounds like an out of balance issue. Did you check to see if you lost a wheel weight? The stick on weights get hot and fall off from time to time if you don't cover them with foil tape.

 

[biggsy]

Sounds like an out of balance issue. Did you check to see if you lost a wheel weight? The stick on weights get hot and fall off from time to time if you don't cover them with foil tape.

Okay that makes me feel a bit better. Last year I used aluminum tape to keep the weights on. I did everything last minute this year and forgot. Once I rebalance them this week I will tape them again. I guess it’s a combination of wheel slip and the weights

 

[Rob-17GT350]

I had the same issue on my ST4/TT4 Camaro. Front and rear tires would both rotate on the wheels. Sometimes like 45deg. It would happen in the first couple laps before the tires got up to pressure causing out of balance and an annoying vibration. Old drag race trick. When the tires are mounted, have the tech spray hair spray on both tire and wheel instead of using the soapy mixture. The hair spray is slippery when wet but tacky when dry. I haven’t had any issues since……don’t knock til ya try it.

 

[blacksheep-1]

I hope it's a balance issue, we spin those tires all over the wheels. I'm pretty sure the balance is for the wheels, the thousand or so wheels that I've done always seem to have the balance spots in the same place or very close to it. The tires themselves,on the other hand seem pretty balanced all on their own.

 

[biggsy]

Just came back from the shop and they rebalanced the wheels. No more vibration. Hopefully the tires are “locked in” and no more slip that bad.
@Rob-17GT350 i relayed your method to them and they learned something new today. Thank you.

so that’s one thing off my post/pre track list.

 

[bnight]

Just came back from the shop and they rebalanced the wheels. No more vibration. Hopefully the tires are “locked in” and no more slip that bad.
@Rob-17GT350 i relayed your method to them and they learned something new today. Thank you.

so that’s one thing off my post/pre track list.

glad this is fixed. I need to do the same with my track tires and rotate some tires around between wheels.

 

[JDee]

The joy of spacers and ARP studs. No need to run different offsets, no need to dismount tires to rotate.

 

[bnight]

The joy of spacers and ARP studs. No need to run different offsets, no need to dismount tires to rotate.

Let's not get into this discussion again. I have a strong preference against spacers.

 

[EF1]

The joy of spacers and ARP studs. No need to run different offsets, no need to dismount tires to rotate.

You may still need to dismount to rotate left to right if running many of the directional treads out there.

 

[EF1]

Just came back from the shop and they rebalanced the wheels. No more vibration. Hopefully the tires are “locked in” and no more slip that bad.
@Rob-17GT350 i relayed your method to them and they learned something new today. Thank you.

so that’s one thing off my post/pre track list.

Slip is never good, but I don't believe that little bit of slip caused your out of balance. I still thing you threw a wheel weight. Like Blacksheep-1 said most of the time you are balancing the wheel. The tires are pretty well balanced as is.

 

[biggsy]

Slip is never good, but I don't believe that little bit of slip caused your out of balance. I still thing you threw a wheel weight. Like Blacksheep-1 said most of the time you are balancing the wheel. The tires are pretty well balanced as is.

Ah okay. My mind was focused on the wheel slip but I forgot about the cause being a missing wheel weight. I guess it didn’t come to mind initially because I tape them down in the past. I missed his (BS-1) comments on that earlier.

 

[JDee]

You may still need to dismount to rotate left to right if running many of the directional treads out there.

Back in the day when I raced we had to run treaded tires. I managed to get sponsorship from one of the tire makers because I was beating their factory team and they wanted their name on the championship winning car. They were General Tire race tires, and they were treaded. Drys were shaved to 2/32" and "wets" were shaved to 4/32".
The tech guy for General told us that it did not matter with their directional tires which way you mounted them, even though they were supposed to be unidirectional. Maybe that was unique to their tires, but they worked just fine mounted either way, wet or dry.
These days I run AR1's and I just rotate as I need to maximize tread life. Front left takes the most beating, rear right takes the least, guess which way I rotate them?
To each his own, you gotta do what you're comfortable with.

 

[bnight]

Back in the day when I raced we had to run treaded tires. I managed to get sponsorship from one of the tire makers because I was beating their factory team and they wanted their name on the championship winning car. They were General Tire race tires, and they were treaded. Drys were shaved to 2/32" and "wets" were shaved to 4/32".
The tech guy for General told us that it did not matter with their directional tires which way you mounted them, even though they were supposed to be unidirectional. Maybe that was unique to their tires, but they worked just fine mounted either way, wet or dry.
These days I run AR1's and I just rotate as I need to maximize tread life. Front left takes the most beating, rear right takes the least, guess which way I rotate them?
To each his own, you gotta do what you're comfortable with.

I also drive AR1's and need to rotate Front right to rear Left because my track is CCW.

 

[EF1]

Back in the day when I raced we had to run treaded tires. I managed to get sponsorship from one of the tire makers because I was beating their factory team and they wanted their name on the championship winning car. They were General Tire race tires, and they were treaded. Drys were shaved to 2/32" and "wets" were shaved to 4/32".
The tech guy for General told us that it did not matter with their directional tires which way you mounted them, even though they were supposed to be unidirectional. Maybe that was unique to their tires, but they worked just fine mounted either way, wet or dry.
These days I run AR1's and I just rotate as I need to maximize tread life. Front left takes the most beating, rear right takes the least, guess which way I rotate them?
To each his own, you gotta do what you're comfortable with.

that is good to know. I try to run non directional tires to facilitate rotations to maximize wear, but I have a set of Hankook RS4s to try next. It is good to know I should be okay rotating left to right without breaking them down.