Wheel Specs Needed

I am having a machine shop make an adapter plate for my Wide 5 wheels so that I can get my wheels balanced on modern machines available in my area.

It would be helpful to know the radius from the center of the hole in the hub to the center of the lug holes in the wheel and/or the dimension of the circle running through the center of all five lug holes.

Can anyone point me in the right direction?

Thanks in advance.

Hey Terry,

I would be interested in a set as well. How much are they?

Tenzin

I don't have a clue about the price because it includes an unknown time factor for all the measurements, set-up etc.

The adapter is just a single 3/4" thick aluminum plate with a center hole cut to match the hub on my tire shop's wheel balance machine and the lug holes tapped to accept the lug bolts off my wheels. The plate will mounted on the balancer and then the wheels mounted to the plate with the lug bolts.

This shop fabricates for a lot of local rodders and they've already made a similar plate for a set of Mustang wheels that had center holes that were somehow damaged or out-of-round. They bolt those wheels up and balance them just like any other.

If it works, I'll get the specs from the machinists and post them here. Any machine shop should be able to duplicate the pattern...Hell, somebody out there probably sells them now. This can't be an original idea.

Can't you dynamically balance the wheels while they are on the car? Back in the 60's I worked at Sears Automotive and we had a machine back then that attached to the wheel that would indicate how much weight and where to place it. The driven wheel was spun up to 70mph and the tech would use the machine to find the proper weight and location. The undriven wheels used another machine with an electric motor to spin the wheel up to speed. The nice thing about this setup was that you got all the rotating mass balanced and not just the wheel and tire. There is a chance that the brake drum or brake disk will add some unbalance to the rotating system. I have not seen such an on-the-car-system for many years, but they may exist somewhere.

The inability to locate such a system is what let to this project in the first place. I would go into a tire/alignment shop and show them a photo of my wheels and they'd just shake their head and say almost exactly what you wrote. Then they say, "What you need to find is an old tire guy who still has the old equipment." After about ten of those I decided to go to Plan B. Apparently, there is one shop in Atlanta (See above), but I'm 80 miles of freeway traffic away from that location.

Terry;
You may be correct that these ancient tire balance machines have gone away. Do you have access to autocad or autocad LT? If so, you can measure the distance between adjacent bolt holes and measure the distance across bolts if you skip a bolt. In ACAD draw a 5 sided polygon and scale it up using a Reference dimension of the distance between 2 adjacent holes as the length of one side of the pentagon. You can draw a circle through 3 points (3 of the vertices of the pentagon) and then measure the diameter of that circle. Use the longer dimension of the skiped bolt distance to construct another pentagon and check to see if the diameters are close to each other.

The bolt circle diameter is the distance between adjacent bolt holes divided by 0.587785 (the Sin of 36 degrees) according to my autocad drawing and some long forgotten geometry.

George,

Please check my math on this. Assuiming the bolt circle has a diameter of 205mm (This from two different fairly reliable sources and confirmed by a fairly precise measurement), we locate a center on the aluminum stock and scribe a circle with a 102.5mm radius. On that circle we scribe 5 marks 72 degrees apart (360degrees/5 bolt holes). These five marks represent the center of the lug holes where we tap to take the bolts. Then we cut the center hole per shaft dimension taken from the wheel balance machine via mocrometer. Finally we cut the stock to fit inside the wheel and balance the whole thing so that when it is mounted on the balancer, the only thing getting balanced is the tire/wheel combo.

Does this make sense to you?

Yes, that sounds to be the correct approach. According to my math the bolt holes should be 120.496 mm apart on the 102.5 radius circle. Good luck with the project.

George,

Yep...Those match my figures exactly...I pulled out my old mechanical drawing tools from my aborted stint in engineering school in the mid-60's and scaled it off yesterday afternoon. Will take it to the machine shop tomorrow.

Thanks for the second look.

I had my wide 5 wheels balanced at Discount Tire..don't know if they are in your area or not but the largest center they had was just large enough to do the job. Good luck, but in my case it has worked fine.

Jim

You can do all of the measurements but a simple solution would be to pick up a wheel adapter from a VW shop and have it modified to allow for the balancer.

Also, I'm in CA and recently purchased tires at America's Tire, they were able to spin balance the tires on their machine.