Vibration between 55mph-62mph

[raman117]

Hey guys, I've got an annoying vibration I'm trying to track down on my '93 Ty, here is what I know so far:

1. With stock wheels at the stock height, there was no vibration.
2. I lowered the back 2" using JTR's kit, and kept the pinion shims to maintain the correct angle.
3. I installed Corvette wagon wheels with used Cooper Zeon 275/40/18 tires
4. I have been told by 2 different tire shops that 2 of the tires have flat spots (they figure the tires were used for drifting at one time).


The obvious answer is that the vibration is caused by the tires, and to get new ones. My concern is that I could go out and spend $500+ on new tires, and the problem will still be there. Is there a possibility that lowering it is also contributing to the vibration? Is there some kind of "fool-proof" test to verify whether it's the driveline or tires?

 

[gstacky]

Re: Vibration between 55mph-62mph

Do you still have the stock wheels, if so put them on and try it.
If you don't, how did they balance the wagon wheels? Is there just weights on the back side, or did they take the time to use stick on weights just behind the spokes? An unbalanced wheel can cause a shake for sure.
Next, where is the shake coming from, the steering wheel or through your seat. If it's through the steering wheel it will be a front balance or tire issue. If it's through the seat it could be rear tire, balance, or driveline issue.
Now lowering with the wrong pinion angle can for sure cause a shake, and with it only shaking at a certain speed, that would be my bet, but check the other stuff first, as it is something you can do quickly without spending too much. If it's still there then more than likely to do with lowering it. But fix it quick before it wrecks something.

 

[GM TURBO]

Re: Vibration between 55mph-62mph

Wheel balance. Ask them to road force or at least a lug-centric balance.

 

[raman117]

Re: Vibration between 55mph-62mph

Do you still have the stock wheels, if so put them on and try it.
If you don't, how did they balance the wagon wheels? Is there just weights on the back side, or did they take the time to use stick on weights just behind the spokes? An unbalanced wheel can cause a shake for sure.
Next, where is the shake coming from, the steering wheel or through your seat. If it's through the steering wheel it will be a front balance or tire issue. If it's through the seat it could be rear tire, balance, or driveline issue.
Now lowering with the wrong pinion angle can for sure cause a shake, and with it only shaking at a certain speed, that would be my bet, but check the other stuff first, as it is something you can do quickly without spending too much. If it's still there then more than likely to do with lowering it. But fix it quick before it wrecks something.

One of my stock wheels has a bend in it, so I don't want to use them. They put stick on weights inside the rim. You can feel the entire vehicle vibrate, including through the seat and steering wheel.

As the tires have flat spots, could that cause the vibration or would it vibrate at *any* speed?

 

[svoguy2000]

Re: Vibration between 55mph-62mph

If the tires are flat spotted then you need them anyway. They may not be all of the vibration but certainly can't help things any.

 

[GM TURBO]

Re: Vibration between 55mph-62mph

I'm saying they aren't flat spotted. I had wheels get diagnosed several times as bent when they used the normal hub centric balance adapter.

What's fun to do is to have them balance a wheel, take it off the machine and have 'em rebalance. It rarely balances out the same on a hub centric adapter.

 

[raman117]

Re: Vibration between 55mph-62mph

I'm saying they aren't flat spotted. I had wheels get diagnosed several times as bent when they used the normal hub centric balance adapter.

What's fun to do is to have them balance a wheel, take it off the machine and have 'em rebalance. It rarely balances out the same on a hub centric adapter.

Very interesting, if I ask the tire shop to balance them using road force or a lug-centric balance, they will know what I'm talking about?

 

[gstacky]

Re: Vibration between 55mph-62mph

Very interesting, if I ask the tire shop to balance them using road force or a lug-centric balance, they will know what I'm talking about?

Yes, the lug-centric is better, but on an OE rim, the hub-centric should work fine, you can tell by spinning them on a balancer whether it is centered or not, most of the time someone tells you that it's a bent rim they just plain don't know what they are doing or don't care.

Now if your tires are junk, get new ones anyways, since you need them, but it still could be driveline, but you won't know until you get good tires on there.

Also, with the stick on weights, I wasn't as clear as I needed to be. Did they balance them dynamically(on both sides of the rim) or statically (only on the inside edge). You can do the dynamic with weights just behind the spoke and on the inside edge, and it will make all the difference in the world. Balancing on one side only is junk and does not work all of the time.

 

[GM TURBO]

Re: Vibration between 55mph-62mph

Yes, the lug-centric is better, but on an OE rim, the hub-centric should work fine, you can tell by spinning them on a balancer whether it is centered or not, most of the time someone tells you that it's a bent rim they just plain don't know what they are doing or don't care.

Had I not seen it multiple times at multiple shops...

The lug centric will be the same price to balance. Road force will cost you a bit more money and only a few shops have the machine to do it (although I bet it's becoming more common).

I ended up buying the lifetime balance at Discount Tire. I was in there quite a bit

 

[AB TY 752]

Re: Vibration between 55mph-62mph

Road force balancing is the way to go. If the machine detects a high road force reading, it will not allow you to continue until a rim runout is measured. The machine may also have you turn the tire on the wheel to bring it into spec. Road force balancing will tell if the problem is in the tires or the wheels or both.

 

[raman117]

Re: Vibration between 55mph-62mph

Road force balancing is the way to go. If the machine detects a high road force reading, it will not allow you to continue until a rim runout is measured. The machine may also have you turn the tire on the wheel to bring it into spec. Road force balancing will tell if the problem is in the tires or the wheels or both.

I think I'll call around and see if anyone has a road force balancing machine. Would larger chain stores be more likely to have it?

 

[AB TY 752]

Re: Vibration between 55mph-62mph

I only know of a couple of places locally here in OK. But if i am correct it is required by GM at a dealership. Both dealerships that i have worked at have them. They are a little pricey so some of the smaller shops may not have one. Good luck.:cheers:

 

[vinnieTy]

Re: Vibration between 55mph-62mph

Google hunter balance machine and goto there site. Theyactually have video how it works and also a link to find a shop local that has it. I think they are the best machines for balancing.

 

[gstacky]

Re: Vibration between 55mph-62mph

Just some thought here, the road force machine isn't as good as everyone is making it seem, even my hunter rep doesn't believe in it. If your tire is bad enough to need to be road force balanced, get new tires. All the road force does is make a bad tire manageable. A good round quality tire will never need road force to balance it. IMO you are just throwing money away if you know already that you need new tires.
Road force to me is like Nitrogen, a complete bunch of BS used to make somebody money, not actually fix a problem.

 

[vinnieTy]

Re: Vibration between 55mph-62mph

Just some thought here, the road force machine isn't as good as everyone is making it seem, even my hunter rep doesn't believe in it. If your tire is bad enough to need to be road force balanced, get new tires. All the road force does is make a bad tire manageable. A good round quality tire will never need road force to balance it. IMO you are just throwing money away if you know already that you need new tires.
Road force to me is like Nitrogen, a complete bunch of BS used to make somebody money, not actually fix a problem.

Every tire in the WORLD needs to be balanced. No matter what brand or what car they go on to. If you plan to purchase a set of tires and not have them balanced then complain about shake what do you like us to say..... Return your tires becasue they are not true round. There are so many things that are round and need balanced, driveshafts for one. And as for your hunter rep hes an idiot to say that. :tup:

 

[gstacky]

Re: Vibration between 55mph-62mph

I never once said they didn't need to be balanced, I said that road force isn't worth the extra money, it is just masking a problem. If a regular wheel balance doesn't solve the issue, then fix the issue. Every tire should be balanced, just like every driveshaft, etc, etc. Like I mentioned in a previous post, even balancing on one side only of a rim isn't good enough, needs weight placed on both sides of the rim. And your balance is only as good as the guy doing it. I do this every day and know that most people/employees are just there to work and don't take the extra time to figure out a problem. My rep believes the same thing I do, a regular balancer, when used properly, is all you will ever need.

 

[AB TY 752]

Re: Vibration between 55mph-62mph

I use a road force balancer nearly everyday. It is true that a regular balancer will do just as good of a balance as the road force machine. But a regular balancer won't be able to determine if the wheel is the problem or the tire. After using one of these balancers i don't understand how it can "mask" the problem, when it is only a measuring device.
You do what you want with your tires/wheels, because these are only our opinions. Good luck.

 

[gstacky]

Re: Vibration between 55mph-62mph

I use a road force balancer nearly everyday. It is true that a regular balancer will do just as good of a balance as the road force machine. But a regular balancer won't be able to determine if the wheel is the problem or the tire. After using one of these balancers i don't understand how it can "mask" the problem, when it is only a measuring device.
You do what you want with your tires/wheels, because these are only our opinions. Good luck.

Exactly, different people giving different opinions, they you choose what works for you.
At one of our shops we have a Hoffman machine that uses lasers to give you a run out reading for both tire and rim, and suggestions how to fix it too. But it still balances the same way as any other balancer.

 

[AB TY 752]

Re: Vibration between 55mph-62mph

Balance and Road force-2 different things. You can balance a tire with excessive road force and the wheel and tire will zero out on the balancer.But the tire/wheel assembly can still vibrate due to road force.

 

[AB TY 752]

Re: Vibration between 55mph-62mph

I looked back but did not see where it was mentioned. Was the pinion angle measured after the drop?
Please excuse my rant. It was not my intention to stray from the subject.