Need advice on fighting the dreaded steering wheel vibration

[AeroF16]

Yes, my thoughts exactly. PS4s aren't cheap and should perform better. Staying on top of mine as well and will stay in touch.

I actually told the manager I was working with "I'll let you balance them a third time if you think it will help, else I'd like to replace the 2 rears." He said he was confident in their ability to balance them correctly and didn't think it necessary to waste time on a 3rd balance and just ordered me 2 new tires.

He was right and I'm glad I found a tire shop I can have some confidence in.

 

[Jimmy N.]

PS4s say maximum 60 PSI, and Hellcat recommendation says 32 PSI (how do they come up with that...EPA?). Maybe the sweet spot for PS4s or any tire for that matter, is something other than 32 PSI? Just curious...

Look at a load chart and you'll see why it's not max psi, but one that's appropriate for the load on the tire.
After all, the tire is merely a container for the air that supports the vehicle weight.

.I know it can be dialed in and not a wheel or car problem.

In your case, I wouldn't say that it's not a car problem. And you know why.
Anyway, I'll have to get back to this. Have an obstinate AlfaOBD to fight with.

By the way, sorry if I forgot to mention that Smart Weight should be off. Must've written that 100 times by now, but apparently not in this thread.

 

[Blickie]

You're right about that!

How can the tire be the problem and the Hunter not figure it out? I've never used one or read up too much on them but it sounds like they should be able to identify a bad tire or wheel.

Is it because there is really no set standard specific to each vehicle?

It's a process. Each wheel and tire is its own entity!
1. Ideally, the aluminum wheel is cast properly with no lateral / radial runout and close to neutral balanced.
2. The tire has no internal issues and is mounted on the wheel with no lateral / radial runout (zero Road Force) along a visual verification while the tire is spinning on the balancer.
3. Now, the Balance Step per the procedures previously outlined steps while not skipping the test weight step. How much weight was needed on the 2 bad tires???? This could be a clue!
4. The only way to improve on these steps is to balance the tire to zero as I shared in another post.

If there is confidence in the above steps, then you have to look somewhere else, including wheel alignment, front end looseness, wheel bearings, new test tire, etc.

 

[Hellcatcfp]

Look at a load chart and you'll see why it's not max psi, but one that's appropriate for the load on the tire.
After all, the tire is merely a container for the air that supports the vehicle weight.



In your case, I wouldn't say that it's not a car problem. And you know why.
Anyway, I'll have to get back to this. Have an obstinate AlfaOBD to fight with.

By the way, sorry if I forgot to mention that Smart Weight should be off. Must've written that 100 times by now, but apparently not in this thread.

Well, thanks Jimmy N. Appreciate your knowledge. Glad you feel like 4 door lives matter too.

 

[Jimmy N.]

It's a process. Each wheel and tire is its own entity!
1. Ideally, the aluminum wheel is cast properly with no lateral / radial runout and close to neutral balanced.
How much weight was needed on the 2 bad tires???? This could be a clue!
.

Okay, here I would like to add that a perfect wheel can be a hindrance. It offers no help whatsoever for using match balancing.

As far as the amount of wheel weights used, I'm still surprised after all these years how often the wheel/tire combo that has the most weights has the lowest Road Force numbers.

To me, the amount of weights needed to Road Force balance is completely meaningless.

 

[Jimmy N.]

So, using your spring analogy, the springs are countering radial forces only, they have no ability to do anything else. Tire pressure is a uniform force, the internal pressure of the tire is applied to every surface inside that volume between the tire and the rim equally. So your springs could get stiffer or softer with pressure changes.

An imbalance in centrifugal forces is what's causing vibrations. Unless higher psi is causing the tire to change it's shape, from a non-uniform shape to something more uniform, it should have no effect.

Heavy spots or irregularities in the tire/wheel are causing the rotation to be something more oblong or elliptical rather than a perfect circle, which is what causes the vibration.

To simplify this, there are two ways you get imbalance from a tire. The uniformity of its physical shape (the visible part) and what's inside the sidewalls.

You can't dismiss how the internals of the carcass react to the weight they're subjected to. If that was the case, there would be no reason to use Road Force balancing in the first place.

You could balance out a piece of 2x4 attached to the tire tread with a regular spin balance (and it would be quite noticeable in real life). Not so with a Road Force machine.

 

[Jimmy N.]

Well, thanks Jimmy N. Appreciate your knowledge. Glad you feel like 4 door lives matter too.

I wish you could bring your dang tires and wheels over here, and I could try fixing them for you.

 

[Jimmy N.]

I agree. Would rather be at 32 PSI (cold) as well. For me, upping PSI has masked vibration for whatever reason? Will figure it out either way.

I may have answered this already (losing track here) but it's sidewall related.

 

[AeroF16]

To simplify this, there are two ways you get imbalance from a tire. The uniformity of its physical shape (the visible part) and what's inside the sidewalls.

You can't dismiss how the internals of the carcass react to the weight they're subjected to. If that was the case, there would be no reason to use Road Force balancing in the first place.

You could balance out a piece of 2x4 attached to the tire tread with a regular spin balance (and it would be quite noticeable in real life). Not so with a Road Force machine.

You're not differentiating and analyzing all the forces acting on a tire separately.

The going in assumption is that the tire is round. Your 2x4 example violates that assumption.

The force from the road that is applied to the tire is separate and independent from the centrifugal force cause by the rotation of the tire and the fact that the mass of the tire is significantly dislocated from the hub.

 

[ChargerChallenger]

WOW WOW WOW this is amazing stuff I mean wow and @Jimmy N. told me since I have in essence a “Taxi“ car it’s always best to have my 4 door “Taxi” car parked outside, Since a taxi is always on call and the tires are always at the current ambient temps. This assures me of number 1 instant access to my Taxi Hellcat and the tires are already acclimated to the present ambient conditions which mean I never have vibration issues. Feel sorry for those taxi cars sitting inside

 

[Jimmy N.]

You're right about that!

How can the tire be the problem and the Hunter not figure it out? I've never used one or read up too much on them but it sounds like they should be able to identify a bad tire or wheel.

Is it because there is really no set standard specific to each vehicle?

It has nothing to do with what vehicle a tire and wheel combo ends up installed on.

Yes, there are separate settings for P and LT tires, but that shouldn't factor in here.
The balancer can figure all this out...given the opportunity. But it takes a coherent operator to take advantage of the information the machine can offer.

 

[Jimmy N.]

You're not differentiating and analyzing all the forces acting on a tire separately.

The going in assumption is that the tire is round. Your 2x4 example violates that assumption.

The force from the road that is applied to the tire is separate and independent from the centrifugal force cause by the rotation of the tire and the fact that the mass of the tire is significantly dislocated from the hub.

I would never assume that a tire is round. That really doesn't happen i real life. Close, yes, but not round.

On the contrary. I tried to explain that the tire's physical shape and its internals are two separate things.
In theory you can have a perfectly round (visually) tire that doesn't balance worth a damn on a Road Force balancer. That's because of the variations in the "spring rates" in the sidewalls.

In a way you're completely agreeing with me when writing "The force from the road that is applied to the tire is separate and independent from the centrifugal force cause by the rotation of the tire and the fact that the mass of the tire is significantly dislocated from the hub."

The force from the road varies due to the sidewalls, and the discrepancies in mass placement are two separate things. Both can be balanced out, especially if the rims aren't perfect.

 

[Stormtrooper1320]

WOW WOW WOW this is amazing stuff I mean wow and @Jimmy N. told me since I have in essence a “Taxi“ car it’s always best to have my 4 door “Taxi” car parked outside, Since a taxi is always on call and the tires are always at the current ambient temps. This assures me of number 1 instant access to my Taxi Hellcat and the tires are already acclimated to the present ambient conditions which mean I never have vibration issues. Feel sorry for those taxi cars sitting inside

ok...here's one for you taxi guys....from a former taxi guy.....

 

[ChargerChallenger]

ok...here's one for you taxi guys....from a former taxi guy.....

View attachment 22822

Your going to give @1971demon a death wish damn she can ride in my Taxi anytime all the time.

 

[AeroF16]

I would never assume that a tire is round. That really doesn't happen i real life. Close, yes, but not round.

On the contrary. I tried to explain that the tire's physical shape and its internals are two separate things.
In theory you can have a perfectly round (visually) tire that doesn't balance worth a damn on a Road Force balancer. That's because of the variations in the "spring rates" in the sidewalls.

In a way you're completely agreeing with me when writing "The force from the road that is applied to the tire is separate and independent from the centrifugal force cause by the rotation of the tire and the fact that the mass of the tire is significantly dislocated from the hub."

The force from the road varies due to the sidewalls, and the discrepancies in mass placement are two separate things. Both can be balanced out, especially if the rims aren't perfect.

Yeah, I'm definitely not questioning your experience, I'm just clearing up the technicalities.

The assumption of the tire being round is valid, as that has to be the point of reference to correct non-round tires to. "Round" would assume completely uniform all around, not just shape but also in density.

How awesome would it be to throw a tire on without any weights and have a perfect balance? Probably possible, obviously not cost effective from a manufacturing point of view.

The machine just tells us how far from that point of perfection a tire is. A basic balancer would tell you, without any external forces applied (i.e. the road), where the imperfections lie and how to correct them.

The road force machine applies a simulated force, from the road, to the tire. Now, it tells where the imperfections are in the tire in a more realistic application.

You cannot "balance out" the force from the road. It is a completely seperate force. You have zero control over that, other than the tires you choose (size, compound, etc.) and the pressure you inflate them to.

 

[AeroF16]

ok...here's one for you taxi guys....from a former taxi guy.....

View attachment 22822

She'd still jump in a Challenger, given the choice.😀

 

[ChargerChallenger]

Ah hell just be done with it already no more vibration but tract variations

 

[Hellcatcfp]

She'd still jump in a Challenger, given the choice.😀

No so sure...but definitely an F16 😅🤣😂🤣😅.

 

[ChargerChallenger]

No so sure...but definitely an F16 😅🤣😂🤣😅.

Yeah the g force just slip those panties right off

 

[Jimmy N.]

How awesome would it be to throw a tire on without any weights and have a perfect balance? Probably possible, obviously not cost effective from a manufacturing point of view.

You cannot "balance out" the force from the road. It is a completely seperate force. You have zero control over that, other than the tires you choose (size, compound, etc.) and the pressure you inflate them to.

Ironically, the two tires that stand out in my mind was a set of steer tires on my Pete. Not an ounce of weight needed.
Now those were very carefully (correctly) mounted on the wheels, obviously including very good cleaning of the rim's bead areas. And they were quality tires.

But you can indeed balance out the force from the road. Again, that's the whole idea with Road Force balancing.