C2 Tire balancing

[Michael S.]

I have noticed a vibration in my '67 327/350 convertible above 40 mph., feels like tires out of balance. I recently installed the '67 bolt on repros. Should the tires have been balanced with the starburst centercaps on ? I did not do that. Front end and rear end is all new, should be fine. Alignment is ok-car tracks and brakes straight.

By the way, thanks to everyone a few weeks ago on my starter issue. Turns out the ring gear had split ! It was new too. Lucky it did not do damage.

[Wayne K.]

Re: C2 Tire balancing

Mike,

If your not concerned about how the factory did it for judging then I'd highly recommend you find a shop that has a Hunter 9700 road force balancing system. This is the best way to balance tires and wheels that I am aware of and can speak from experience.

Wayne

[Duke W.]

Re: C2 Tire balancing

Were the old or new tires installed? What make, model, size? Were they balanced statically or dynamically?

Duke

[Michael S.]

Re: C2 Tire balancing

Duke-

Tires were/are new. Firestone Affinity P215 70R 15. I am not certain what type of balancing- I can call the shop. I got the "standard" balancing deal, guess I am learning.

Thanks

[Duke W.]

Re: C2 Tire balancing

Take them back to the shop and have the balance checked. Static balance would have weights only in one plane - like the inside. Dynamic balance would have weights in two plans - Both inside and outside, but to avoid marring the wheels I would not have clip on weights installed on the outside. You can achieve dynamic balance by using stick-on weights on the drop center as far outboard as possible and stick-on or clip on weights on the inboard side.

The hub caps should not have a significant effect on balance.

While spinning on the machine look across the tread crown and get a feel for how much out-of-round is evident. If it's more than a spark plug gap you will likely feel vibration.

If the balance is okay, the setup should be checked on a Hunter 9700 for wheel/tire runout and radial force variation. A 9700 is both a conventional static or dynamic balancer, but also has the additional capbilities.

In my experience as you go up in tire quality, as indicated by speed rating, you get a rounder tire.

Duke

[John H.]

Re: C2 Tire balancing

Go to www.GSP9700.com and you'll find a locator there that will show you the closest dealers/shops to you that have a Hunter GSP9700; it not only does precision two-plane dynamic balancing, but also measures lateral and radial runout, loaded radial runout, and loaded radial force variation. Just "spin-balancing" found at most tire stores doesn't address all wheel vibration issues - the Hunter machine does.




Hunter GSP9700 Locator

[Rick S.]

Re: C2 Tire balancing

John,
What is the approx charge per wheel in the Detroit area?
Rick

[Terry M.]

Price in Chicago

I know it is not your question Rick, but for others on the board:
Three years ago I paid $7 each for Caprice wheel & tire balance on a Hunter GSP 9700. I brought the wheels & tires as a mounted assembly to the shop. All they did was put them on the machine, set it up, spin it, and put the weights on. It was not the kind of shop John pictured. This place sold tires for earth movers and fork lifts. They didn't even have a lift in the shop, but did have a huge press for pushing solid rubber tires onto fork lift rims.
Would I have paid more for the wheels and tires if I told them they were from a Corvette or a Cadillac? We'll never know.

BTW, John: Nice picture.

[John H.]

Re: Price in Chicago

I took five wheels with tires mounted on them (in the corner of the photo) and a loose set of five new tires to the shop (local Chrysler dealership); they dismounted the old tires, mounted the new ones, did the full GSP9700 process on each one, and I just took pictures and learned more about the process from the technician (in addition to what I had gotten directly from Hunter Engineering earlier). Cost me $100.00.