rmackintosh

I am putting in an order for race wheels for the car.

Pretty sure it will be a 315/335 combo with 11x18 in the front and 13x18 in the rear.

My wheel builder has asked for the following measurements:



He says he needs D, C and F for the front and rear.

I think D and F I can get, but C is measuring from the hub face to the bead seat of the wheel.

Anybody have some love for me, or any other measurements that might make him happy?

Thanks so much!!

froggy47

For what car? Need to clear fenders? Care about front full lock?

rmackintosh

Sorry....

C6

World Challenge body work....Z06 fender profiles

Can cut anything under fender....race car only

Front lock is preferred, but not necessary....race car only

rmackintosh

Ok, how about this...if I go 11x18 and 11x13 how much bigger is that than stock Z06 wheels?

And, for those that did it, did you put all of the extra width to the inside or the outside of the wheel, or split between the inside and outside???

Thanks.

yooper

same question!

froggy47

steponc

It appears C will determine what clearance value you can have to clear everything on the inside of the wheel well, frame, shock mounts, coil over springs, control arms, etc.

I would take these measurements at ride height, full droop, and full compression if possible.

You should also keep the tire section width and radius in mind since they are wider and taller than the rims, Also the suspension moves in and out as it travles up and down.

The manufacurer requires these measurements from you to eliminate any liability for a rim that will not work after being delivered to you. So measure everything twice at least.

trackboss

8" of backspace is about the most you can use in the rear. You might be able to use a little more if you don't have the liners in place or you modify/remove the tub.

rmackintosh

OK....any info on the fronts?

Thanks.

trackboss

When I had CCW track sized wheels (18x12R and 18x11F) on my stock C5 CCW said the front bs was 8.25" and the rear 8.75" What I doesn't make sense is that my jongbloed rears have 8" BS and they fit the same as the CCW's. It may be that CCW measured to the outside edge of the wheel as opposed to JB measuring to the bead, but I'm not sure. With a 345 mounted on my 12" JB wheels I have about 1/2" clearance between the sidewall and the wheel liner. I disconnected the spring and cycled the suspension to check. With the same wheels and pirelli slicks the tires just barely rubbed the liner on the track. Keep in mind those were tall tires.
On the front the 11" wheels rubbed the control arm at full lock, but other than moving around in the paddock you shouldn't have to worry about that and when they do rub you will immediately know. If I were you I'd install some small steering rack spacers. I know ford sells them in various sizes, but you can also make your own from some plastic pipe. They just snap over the rack shaft.
In genereal you want to use as much backspace as you can to keep the scrub down.

trackboss

I should have my rear wheels back next week and once I mount the tires you are welcome to borrow one to try and use as a reference for what you need on your car.

rmackintosh

This helps....A LOT! Thanks

My wheels will be Jongbloeds as well. I am talking with Ryan right now.

You said that the rears had a 8" backspacing number from Jongbloed....they do measure to the bead, not the rim if you look at the diagram above. Do you know what the backspacing number from Jongbloed was on the fronts?

Lastly, is this on a C5 or C6 car you are describing clearances?

Thanks, I may take you up on bolting them on to check....where in the bay area do you live? I live in Danville.

Randy

trackboss

I don't remember what the 11" fronts were on the jb's, but when I get a chance I can measure my 10's. I think the 11's were 1/2" more.
This is on my C5, but it should give you an idea. I now have aftermarket rear fenders that are about 2" wider and the 12" with 345/30-19 clears on both sides pretty well. It's a pretty tall tire. A little over 27". Equivalent in height to a 690 slick. The pirelli slicks I had were 305/680-18. So a little shorter, but taller than a typical hoosier 335 DOT.
I'm assuming you are going to run the R100. If you go to the 710 tire figure 1" overall larger diameter so half that on the radius compared the the setup I have now.
I'm in san francisco.

gkmccready

Stock C6Z is 18x9.5 275/35r18 Front, 19x12 325/30r19 Rear. CCW fits 18x10 or 18x11 fronts with 18x13 rears on the Z's. On my non-Z we had 18x11 fronts with 8.25" back spacing, and 18x11 rears (different bs) -- with the Z fenders you should have plenty of room for your proposed 11s and 13s. On a non-Z the 11s in the front were really tight and I fought some (outside, painted) fender rub that I later figured out was likely to be the camber plates pushing the track too wide for only running -1.8deg camber. (ie. Spacing the front uppers out too far to clear.)

I recently priced JB versus CCW and I think CCW is going to continue getting my business even though they're in Florida versus semi-local... plus my dealing with CCW have always exceeded my expectations.

rmackintosh

I have had both CCW and Jongbloed and liked both. The CCWs are a fine race wheel, but they lack much "style"....at least the Classics that I had did. Nice durable wheel.

The Jongbloeds I had were on another level finish wise however. They looked like a really nice custom street wheel and were very well finished with smooth anodizing vs the rough finish on the CCWs. They were just much, much better looking wheel.