Wheel Balancing

[bstandley1]

I recently had my 15" Compomotives rebalanced on a Hunter 9700 Roadforce system and had the wheel weights attached to both sides of the rim. I'm still experiencing some vibration at the 66-70 MPH, so I went back to the shop. They suggested that since the Compomotive wheels are lug centric, the installation of hub centric rings on the wheels would result in more precise centering of the wheels on the hub, thus eliminating the vibration.

Have any of you folks ever installed hub centric rings on your wheels and if so, did they do any good? I sure would like to make this problem go away .....

Bob

[nolastyankee]

Bob,
Can you explain hub-centric and lug-centric? This will be a learning opportunity for me...Thanks!

[bstandley1]

Brian,
I lifted the following from the American Racing Wheels website:
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What is a Center Bore? Hub Centric vs. Lug Centric

The centerbore of a wheel is the size of the machined hole on the back of the wheel that centers the wheel properly on the hub of the car. Centerbores on wheels are typically a standard size by brand or size (measured in inches or mm). Hub sizes vary by vehicle brand and style.

When this hole is machined to exactly match the hub so the wheels are precisely positioned, minimizing the chance of a vibration, it is said that the wheel is “hub centric”.

Some wheels require centering rings that lock into place in the back of the wheel in order to become hub centric and reduce the risk of vibration while driving. This is an acceptable alternative.

If you don’t not have hub centric wheels (lug centric), they should be torqued correctly while the vehicle is still off of the ground so they center properly. The weight of the vehicle can push the wheel off-center slightly while you're tightening them down if left on the ground.
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If you Google "Hub Centric Rings", you'll find any vendors selling them in a variety of sizes...
In the mean time, my quest for properly balanced wheels continues!

Bob

[Mike Del]

I've found that the usual culprits are the tires. Most of the muscle car tire sizes are poorly made. They will appear to have balanced properly, when in fact they just can't be balanced. Check the reviews on Tire Rack (www.tirerack.com) and you'll get the picture. I have used several different manufacturer's tires on 15" rims and I'm now running Yokohama tires with no problems whatsoever. Yeah, they aren't the "original" manufacturer. You original guys vibrate along and I'll be the smooth ride in front of you. Hope this helps.

Mike

[JeepSnake]

Agreed with Mike - you're lucky if you can keep a tire balanced these days. I don't know if the fibers & cords, etc. shift around, or what the deal is. But, the '84 Cutlass Supreme I used to have was very sensitive to balance, and within a week of having the tires balanced, they'd be jumping again.

Brian, the best description is that hub-centric wheels are centered on the hub assembly by indexing on the actual hub that sticks through the center hole of the wheel. Bolt-centric wheels are centered on the hub assembly by the tapered-seat lugnuts centering into the matching tapered-seat lug holes in the wheel. (You'll see bolt-centric wheels move and "center up" as you start snugging up the lugs.)

I could see where this could introduce some variation, as the balancing machines are typically set up like a knock-off hub, but I believe that tire quality is still going to very much dominate the balancing equation.

[bstandley1]

Thanks for your thoughts ... I'm inclined to believe the problem is with the tires. What I want to avoid is buying another set of tires and still have a vibration problem. Clearly, the Yokohama Avid S/T is a big favorite of the cobra replica crowd and if I knew it would solve the problem, I'd buy a set in a New York minute!

I really don't have much faith that the hub centric rings will solve the problem. I took a close look at the Wilwood hub and it has a gradual taper on it, making the calculation of the outer diameter a challenge. According to Wilwood's rep, "The diameter on the hub where it begins to be flat (outside of the radius) is 3.06". That dimension is larger than the inside diameter of the wheel hub ....???

I think there's another trip to the tire dealer in the near future....

Bob

[nolastyankee]

Thanks for the explanation guys...Good learning!

[bstandley1]

Just a footnote:

Had the local Discount Tire dealer do the Hunter Road Force Variance drill on my car today ($80). After matching the wheels and tires, they ended up with the following road force variance:

Front left 11 lbs
Front Right 21 lbs
Rear Left 12 Lbs
Rear Right 11 lbs

The original reading on the front right was 42 lbs! The front vibration is markedly improved, but there is still a bit of wheel vibration near 70 mph. The Discount Tire guy recommended I go back to the original tire dealer and see if they're willing to swap out the front right. If all else fails, a set of Yokohama Avid S/Ts will be the final solution.

Bob

[will butterworth]

likely go to yoko,s next.Took red to gadsden place Maurice suggested, spin bal. on car, fellow rolled tires on front up to speed and you should see the tire distortion,clearly visible with the eye, dang tire hopping like a rabbit.Have about 10,000 miles on them.Will-alabama

[rdorman]

Just a footnote:

Had the local Discount Tire dealer do the Hunter Road Force Variance drill on my car today ($80). After matching the wheels and tires, they ended up with the following road force variance:

Front left 11 lbs
Front Right 21 lbs
Rear Left 12 Lbs
Rear Right 11 lbs

The original reading on the front right was 42 lbs! The front vibration is markedly improved, but there is still a bit of wheel vibration near 70 mph. The Discount Tire guy recommended I go back to the original tire dealer and see if they're willing to swap out the front right. If all else fails, a set of Yokohama Avid S/Ts will be the final solution.

Bob

Geesh that is a bunch! I think I had one Yoko over five pounds and one of them was ZERO!

[bstandley1]

Rick,

Thanks for the feedback ... I was wondering what kind of road force variance was achievable with the Yokos. I'm still going to have the dealer swap out the front right tire .... but I won't be surprised if it doesn't completely eliminate the vibration.

Bob

[chris knueven]

boy after reading this thread i am not even going to mess with my radial
t.a.'s. i will call tire rack and get a set yokos coming before i get the car
back on the road........

chris

[bstandley1]

Chris,

You are a wise man!!!

Bob

[bstandley1]

The Final Update:

The tire dealer replaced the front right tire; road force variance was 12 lbs. They also commented that the lateral run out on the wheel was .016. From what I can find, lateral run out is acceptable on alloy wheels up to .020. Took the car for a forty mile test ride ..... no vibration up to 80 MPH!! Life is good!!! Think I'm done with tires for the season.

Bob

[Slither]

Bob,

What tires are you running... did I miss that somewhere in the thread:confused:?

Thanks

[bstandley1]

Paul,

There a private brand label manufactured by the TBC Corporation. They make tires for Big O Tire, NTB, Les Schwab and a host of others. I bought them before my tire education started....

Bob