68 Camaro, wheel backspace(DSE quadralink n subframe)
 

Hello,
I'm moving along on my 68 Camaro convertible project. I want to get some wheels ordered in the next couple weeks. I'm looking for some recommendations for width and backspacing. I'm sure this is a question that gets asked every other day. So if there is a recommended way to get measurements easily to fit big tires on these cars, please lend some advice.

Here are my guidelines.
The front suspension has the DSE narrow subframe, with the C6 vette uprights. An 18" wheel is the min. diameter here.
The rear is DSE quadralink setup with coilovers. and the DSE minitub kit. The 9" rear axle measures 56.5" wide from mounting flange to mounting flange with the brake rotors mounted. I'd like to run an 18" wheel in the rear also.

From poking around here, it looks like I can run 335mm rear, and 275mm front tires. And keep the diameter of the tires at about 25-26", close to the stock diameter.

Can I squeeze anything wider in the front? 295?
Is anyone running the above widths on a '68 with similar chassis/body mods. What backspace am I looking at for this setup front and rear.

Here are some pictures of the rear wheel wells, I thought they might help. You can see the frame notch for the minitub job.

http://www.denverspeed.com/gallery2/...2/DSC01881.JPG

http://www.denverspeed.com/gallery2/..._3474.JPG.html

call dse , they are very well informed on wheel sizing and backspacing.

Thanks guys.
The 255mm max width on the front is disappointing. I talked to the guys at DSE, Apparently the problem is not rubbing on the subframe, but rubbing on the outer fender lip when the tire rotates around. The inner edge of the tire swings toward the outer fender as you turn the wheels. Thats how it was explained to me. I guess its a problem with the 67-68 shaped fenders. The 69s have longer openings, and more room for bigger tires.

Here is the wheel combo recommended by DSE:
18x11 rear, 5" b.s. with a 315/35/18
18x9 front, 6.125" b.s. with 255/35/18

I think thats what I will go with unless anyone has any reason to try something else. I was thinking of just limiting the steering rack and go a bit wider on the front. Is that a possiblity?

Looking around at tires, I think I can go to the shorter 315/30/18 on the rear. That will make the sidewall heights match up better front to rear.

we should check the scrub radius on that front end then - if I understood that correctly it sounds like that front was set up too narrow, so you run a wide tire with less backspace and get scrub - as the tire scrubs around it sweeps and arc (zero scrub means the tire would perfectly pivot at it's centerline, which you don't want either due to vague/no feedback at the wheel) and runs the outer edge into stuff. My 914, of course, REALLY sweeps and arc with the struts and 10" fronts as I have a lot of scrub in that setup.

the old 'stang with the big front tires on deep dish wheels would sweep around and the outside edge would grab the lower valence so I had to be careful with the U-turns back then... too much scrub is the reason. Fortunately that car and the Camaro have pwr steering :D

We run 275s on the front of the MotV8tr, Call me.

Hey Frank. Im a bit scarce here, and I didnt see your reply right away. I'll try to drop you a line tomorrow. I see you have been helping alot of people with wheel sizes around the forum. I appreciate the help.

For what its worth. The wheel choice is moving to 19" diameter Asanti 3 piece deals. I need to look around for tire selection for that size wheel. Thats beyond the outer limits for my knowledge.

We can handle it all

I am traveling to South Florida for a photo shoot tomorrow for one of our cars, I will be on the road from 11AM to 2PM eastern, perfect time to chat.

update
 

This wheel selection problem keeps evolving. I did some searching for tire availability, and ended up in a slightly different place than I started.

Here is where I am now.
Front: 19x9 +30, I want 6.2" backspace.
255/30/19 tire

Rear: 20x11 -20 I want 5" backspace
305/25/20 tire

I saw Yokohama Advan Sports, Pirelli P Zero Nero, and Michelin PS2 in these front/rear matching tire sizes.
The fronts will be 25" tall, the rears 26" tall. I wanted to keep the sidewall sizes the same in the front and rear. This seemed aesthetically important after looking at some pictures here and other places.

How do my wheel and tire width's sound? I was shooting for a wheel width 1" narrower than the tread width. Is that going to look bulged? Right on? Stretched? I know how to do the math, but things are not always how they seem with tire widths.

Here is the wheel choice today. It will be something from Asanti more than likely.

Attachment 16726