1972 tire balancing

[Jerome E Pederson]

I have been told the best way to insure your tires are properly balanced is to have them dynamical/spin balanced and weights balanced on both the inside and outside of the steel rim, as required.

However, I have been told that earlier model Corvettes (1972 for example) did not have weights placed on the outside of the rim and were only placed on the inside.

Is this correct?

If so, was there a reason(s)?

What is the position of NCRS if weights are found on the outside of the rim during judging?

Any insight will be appreciated.

Thanks

Jerry

[Chuck S.]

Re: 1972 tire balancing

Yes.

Balance weights on the outside of the rim interfered with the proper fitting of the trim rings.

If balance weights are visible on the outside of the rim, you WILL receive a deduct. (Are you kidding?...They even look to see if they are the orignal style weights! )

Suggestion: When your wheels are balanced, discuss this with your tire technician...you can even go so far as to tell him "no weights on the outside", but be advised your balance will not be optimum. Weights on both sides of the wheel provide the optimum balance, and with newer technology, better than "1972" wheel balance can be achieved.

This is another reason to have two sets of tires/wheels if affordable...one set of rallys with repro tires for judging, and another set of cool aftermarket wheels with modern steel belted radials for driving. Of course, if you have a trailered garage queen, then you can dispense with the second set of tires/wheels altogether, and wheel balance is almost a moot point.

[Joe L.]

Re: 1972 tire balancing

Jerry-----

All Corvette wheel/tire assemblies, at least through 1982, were static-balanced only; no dynamic or "spin" balancing was performed. Why? Well, I assume that GM felt that such a balance was adequate for PRODUCTION purposes. In virtually all cases, especially with new wheels and tires, it will be fine. There was also a requirement that not more than a total of 5 oz of weight be used for any wheel and tire assembly. A wheel/tire assembly static-balanced within this requirement is very likely to demonstrate adequate in-service balance characteristics.

From 1968-1971, wheel weights were applied to the inside rim only. I believe that, primarily, this was to ensure that there would be no interference with the trim ring clips once those were installed. However, with a static balance limited to 5 total ounces of weight, there should be no real problem with inside-only installation of balance weights.

From 1972 onward, the same basic requirements as above continued. However, specs then allowed for the splitting of weights if the total required weight was in the range of 3 to 5 oz. This was not an assembly requirement, but was an assembly option. How often it was exercised, I don't know. My guess would be rarely, if ever. In addition, I think that it would be fairly unusual for a factory new wheel and tire to require 3 ounces or more of total weight, so the exercise of the option would rarely present itself.

I believe that the JG specifies that wheel weights for 1968-72 models be only on the inside of the rim. Presumably, other than this would merit a deduction.

[Terry M.]

Re: 1972 tire balancing

If the best wheel/tire balance is a concern find yourself a shop that uses a Hunter GSP 9700 Road Force system. use the link to find a shop near you.

Talk to them before you bring your wheels and tires there and tell them what you are trying to accomplish -- good balance compatible with judging rules. They can put adhesive backed weights, hidden by the trim rings or wheel covers, near the outside of the wheel to accomplish both goals. If they seem inflexible, or look at you like you have several heads, go to another shop with that equipment.




Hunter GSP 9700 locations