Choosing The Right Heidts Suspension

My 40 Chevy coupe presently has a Corvair front suspension under it with 14" wheels. After researching different companies, I have decided to go with a Heidts suspension. My problem is that when I go to order it, what should I order?

I do want the stance dropped a bit and am thinking of going with 17 or 18 inch wheels. Since the suspension is from a Corvair and not original, I don't know what the factory height to center of hub was. I'm assuming that the Corvair center hub height is not the same as factory. Then to make matters worse for me, I don't know what the original factory wheel size was.

Wouldn't I need to know what the original ground to center of hub measurement and then compare that to present center of hub to ground measurement to see how much higher or lower car presently sits and include the difference in wheel size? Wouldn't this give me my base to know if I wanted to order a standard or dropped suspension to get the stance I want. If I changed from the 14" wheels to 17" wheels, wouldn't that actually raise the height 1 1/2 inches?

I'm confused!!! Am I over thinking this? There must be a more simple way to figure this out. Any insight on this would be appreciated, thanks.


Bill

The tire size will affect your ride height more than wheel size. For example, for most of these fat fendered cars people might use a 24-26" diameter tire on front and a 27-29" tire on the rear depending on desired ride height, clearance, etc. Here's a tire size chart that might help you with tire dimensions - Tire Size Chart

As for which Heidts to order, I suspect the crossmembers all mount the same in the frame and to get lower you use drop spindles. I think they also now offer a bolt in kit but you may have to do some frame rail repair depending on how the Corvair suspension was installed.

As Randy said, the only thing that determines the height of the tire is the tire's diameter, wheel size has nothing to do with it. If the tire diameter is 26.5" tall, doesn't matter what size the rim is other then tire size and rim size of course have to match. Heidt's packages normally set the car about 5" to 6" off the ground, a dropped spindle would lower that 2".

Bill, you really need to decide what you want to run for tire size before you go too far. IMO the tire size, and more important the tire profile are a key factor in the car looking "right". For me I simply cannot abide a set of rubber band tires riding on Donk wheels for any street rod or muscle car. I want to see some sidewall, thank you very much! Like Dave says, your tire diameter is a critical value, and a fat fender car is different from a highboy in what's "right". On a highboy the old tradition is a six to eight inch rubber rake, i.e. 31" rear OD, 24" front OD hits the middle. Pick your tire OD, then focus on the profile to get your wheel size, and set up your suspension to achieve the ride height that you want. It doesn't matter what the original tire/wheel size, ride height or Corvair dimensions were.

Was the Corvair suspension grafted onto your original frame rails, and are the frame rails still fairly intact? Or, is it an entire Corvair subframe? If the original frame is still intact, you can just lop off the Corvair parts and Heidt's can tell you your options on tire size, etc.

Here's a few variations on ride height and tire/wheel sizes that you might find interesting:
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I was having real issues trying to decide what tire and wheel combo to go on my 40 when I changed all my suspension around. The only thing I can really say to you is, try this. Get some plywood and cut a 24" or 26" circle. Drill a hole in the center and then drill your bolt pattern in the wood. Make 2 for the front and 2 for the rear at 29" or bigger diameter. You can bolt these on your car then using jacks lower the car down and settle the suspension enough to get an idea of what the car can look like. It can be a bit of a job to do this, but then at least you have an idea before you take it apart. Mine is a guessing game until I put the body back on. I've seen guys use card board to do this too. Either way, just be careful setting the car back down with the wheels off. You could even just put 4 short jack stands under it if you have short enough ones.