Wheel size and tire size specific to performance driving

[BTF/PTM]

All the suspension talk is cool, so keep it going, but let me ask a related question. Any recommendations on where one could get a set of steel wheels made that are 15x8 and the proper lug pattern and offset? As previously mentioned, I keep finding only truck and musclecar options.

Also, it turns out that the Konig rewind isn't available in 15x8, so would the Rota RB 15x8 with its +4 offset still clear the fender wells?

[jmortensen]

http://www.bassettwheel.com/dhole_asphalt.html or www.diamondracingwheel.com. Bassett looks to be a better deal. Diamond has prices from the 90's on their site and when you actually order they will hit you with the new price. Can't help on the fitment question, but I'm sure that info is here or at hybridz.org.

[BTF/PTM]

Beautiful, thanks.

I do have a new question that's come up while doing some research. How is it that a wheel with 8" width and zero offset manages to have 4.5 inches of backspace? Shouldn't that wheel have 4 inches of backspace plus whatever the flange thickness is? That one eludes me. I want to make sure I'm ordering the correct size of wheel. If I order a set of 15x8 wheels with 4.5 inch backspacing, is that the right wheel set?

[John Coffey]

Ignore offset and focus on backspace when ordering custom wheels. I used to run a 15 x 8 custom wheel with 4.5" of backspace but I had to run coil overs to gt the proper clearance. Some people claim to fit this wheel with the stock 5" OD springs but I'm skeptical.

I haven't heard the term roll couple in a while. Currently in suspension setup we treat each end of the car as as separate item and roll couple may only come into play when calculating total roll stiffness as part of the anti-roll bar design.

[jmortensen]

The way backspace is measured is to lay a straightedge on the rim and then measure to the mounting flange. So if you have a 15 x 8 the actual rim edge to rim edge is probably 9 or 9.5 and that's why it doesn't work out like you might think. I think steel rims are particularly bad with that because they have the lip on the rim for weights.

[BTF/PTM]

Here's another question. One of the steel wheel manufacturers can build a set of 15x8's that weigh about 17 pounds each. Not great, but becomes great when the price of 80 per wheel is factored in. Now, here's the question - does "not DOT street wheels, off highway use only" mean that these wheels are not mechanically strong enough to put up with potholes and bumps and all the other things associated with street driving? The "street" wheels they build jump up to 25 pounds each.

[jmortensen]

Yes, that's what it means. Lightweight steel rims have spun shells which are usually .095" thick steel. The cast steel wheels have much thicker shells and can take a pothole hit without any trouble.

Seems like I keep posting this vid, but I could watch metal spinning all day long.

[BTF/PTM]

Yea, that video is pretty sweet =)

25 pounds per wheel is a lot of weight at each corner, maybe the Rota RB with +4 offset is the best option. Thanks for the continued feedback!

[jhm]

If you're looking to lower your car and reduce unsprung weight, have you considered 13" wheels?

http://www.datsunclassifieds.com/showproduct.php/product/6543/title/13x7-race-wheels-2ftires/cat/4

[BTF/PTM]

I've done more research, and have a couple more ideas to toss out for review. It's looking more and more like a 225 50r15 on a 15x8 wheel requires either custom wheels and coil-overs or altering the body to avoid rubbing fenders or chewing up the front valence in a tight turn. That said, a sticky 205 is already more traction than these cars had in their day, and as a fledgling z driver I'm sure there are numerous track and autocross tires for a 15" wheel that will offer more than enough grip as I learn to drive the car. Any insight on any part of my ramblings is welcome. Thanks, everyone!

Edited December 19, 2011 by BTF/PTM

[jmortensen]

How fast do you want to go, and is it worth it to do the job twice? On my project I did everything at least twice, sometimes 3 or 4 times. In hindsight I would have saved a bunch of money if I had just figured out that I was going to end up at 10/10ths and hadn't spent the money to go 6/10th, then 8/10ths, then 9/10ths, then finally built it as crazy as I could.

15x7's are pretty small. Yes, you can have a car that handles pretty good on 15x7's, but will it be fast enough?

[BTF/PTM]

A solid argument, if ever there was one. Sounds like the recommendation is to work for getting those 225's under the fenders =)

Thanks!!

Edited December 20, 2011 by BTF/PTM