The last word on the 18" wheel / '68 Camaro Conundrum.

[trapin]

After some of the most death defying and intense research in the history of mankind I think I have finally unlocked the formula to this loooooonnnngggg debated question. I have scoured the Message Boards and studied the famous Chryssos thread (even discussing the issue with it's author at great lengths via PM). Here's what I know; the 1969 Camaro does NOT apply here (different wheelhouse), 17" wheels also do NOT apply here (we're discussing 18" wheels), also 9.5" wheels are NOT possible as the 18" rims I'm using are not offered in a 9.5" hoop (Boze Forged).

Stock body 1968 Camaro...NO minitubs.

Front - 18X8 (4.875" BS) 245/40R18
Rear - 18X10 (5.75" BS) 285/40R18

And how is the rear wheel/tire package made to fit? Per my discussion with Steevo, by rolling the wheel lips, baking in a little more backspacing (5.75 vs. 5.5) and adjusting accordingly with wheel spacers.

So what do you think? The last word or what?

[rob07002]

Tony, what are your thoughts on a 18x9 for the rears? I have 18x10's with a 275 tire right now and I honestly don't like the way the tire sits flat, actually tucked inward when looking straight down the wheel.

I prefer a slight bulge (wife too, ha!) I have 255/35/18's on a 18x8 in the front and they look much better.

Of course since you are going with absolute ZERO tolerance for error, this may not work.

[trapin]

I'm just worried the 18X9 will look too skinny, that's why I wanna go 18X10. To alleviate the "tucked inward" look and give it some bulge I could go 285 in the back. Steevo has proven that it will work.

Do you have any pictures of your car's wheels and tires?

[eville]

It's the measure twice, cut once that kills me. Measure, measure, measure.

Frank (prodigy) told me when I ordered my wheels, on a stock first gen, there was 3.25" 'front space'. If you want to go wider, it all has to go to the 'backspace' or the tire will be in the fender. In the back, you have a little more flexibility.

A little too much BS and you can take care of it with a shim. Not enough BS and you have to remake the wheel. I don't like shims, so I ordered my wheels first with a bit too much BS, figured out the necessary massage and then I ordered my new Moser with a custom width.

Without measuring I'd be leaning towards a 6" or so BS on a 10" wheel.

Good luck.

[trapin]

I'm going with (Boze Forged "Pro Touring"). They are two piece and the wheel rings come in either 9" or 10". My last wheel and tire in the back was a 17X9.5 (5.5 bs) with a 275/40 R17. Right now I measure 11 1/2" from the back of the wheelhouse to the wheel lip. If I roll the lip I'm guessing I can gain another 1/2" which means the 285 will fit inside that space with a little room to spare. Then the trick is nailing the backspacing or baking in a little more backspacing into the wheel and adjusting with shims. Nitto shows the 285/40 R18 is 11.42" wide. So if I have 12" to work with (6 1/2 from hub face to back of wheel house then I would want 5.5" of backspacing to leave me a 1/4 inch inside and outside. And from there I would bake in another 1/4 inch of backspacing to give me 5.75" and I'm in the ball park and can adjust accordingly. I may actually go 5.85 backspacing just to be safe. I don't mind wheel shims.

[Magntik]

It worked for me.
Frank helped me measure, then ordered the 18 x 10's. Warned and warned it would be tight.
I read Steve's thread and rolled the lip and hammered on the wheel tub.

I even ordered a Skulte spacer.

And... VERY, I'm VERY HAPPY!!!

Only thing, last minute worried and taking Frank's concern for the fit, I "skinnied" out on the tires and went 275/ 40 /18.


Soon as I burn these up the next pair will be 285's.

[rob07002]

I'm just worried the 18X9 will look too skinny, that's why I wanna go 18X10. To alleviate the "tucked inward" look and give it some bulge I could go 285 in the back. Steevo has proven that it will work.

Do you have any pictures of your car's wheels and tires?

Well the 285 is what, about 1/2" wider, so that may look a little better, I just know a 275 on a 10" wheel doesn't look right to me and looks like the wheels you see on low riders, tucked in slightly.

I think I do have some pics and will try to send to you tonight.

[trapin]

Thanks Rob.

Magntik.....do you have any pics of your rear tire set up? Also....why did you hammer on the wheel well? From what I got from Steevo's thread the adjustments to the wheel well were only needed for the 295. Also, what backspacing did you end up ordering them with and what thickness Skulte Spacer did you have to use?

[buickfunnycar.com]

It worked for me.
Frank helped me measure, then ordered the 18 x 10's. Warned and warned it would be tight.
I read Steve's thread and rolled the lip and hammered on the wheel tub.

I even ordered a Skulte spacer.

And... VERY, I'm VERY HAPPY!!!

Only thing, last minute worried and taking Frank's concern for the fit, I "skinnied" out on the tires and went 275/ 40 /18.


Soon as I burn these up the next pair will be 285's.

Same here.My car...while not a '68...is running an 18x10 rear (5.625" b/s) with shaved wheel pads and a 275/40 tire and I still have tons of room to the outer fender.I recently installed small 5/16" spacers to bring them outward a bit.I am still running stock rear drums in the rear so I figure when I switch to discs,they'll be about 1/4" further outward...should be perfect.I may switch to 285/40's at that time:
https://static1.pt-content.com/images/noimg.gif

These pics were taken before the shims were added:
https://static1.pt-content.com/images/pt/2008/07/DSC05657-1.jpg

https://static1.pt-content.com/images/noimg.gif

Again...great fitment advice from Jon Henson @ www.driverzinc.com

[trapin]

I'd feel funny calling them since I'm not a customer.

[buickfunnycar.com]

I'd feel funny calling them since I'm not a customer.

But you could be....:yeah:

[trapin]

I could, but my heart belongs to Frank at Prodigy. LOL!!!

You know I did a sectional drawing of this on my computer during my lunch break and I even dialed down my measurements to millimeters (1 inch = 25.4mm) and the end result was 5.5 inches of backspace to center the wheel perfectly within the 12 inches of space available.

Hmmmm....

[ProdigyCustoms]

Steve is correct. Adding a quarter inch of backspace will center the extra half inch of tire. We just did some 18" Forgeline with 285s on Danny's 67 on 9.5s with 5.5 backspace. It is super tight with no lip roll. We actually had to do a little adjusting on the rear end wheel opening centering the rear to make them clear.

You should be fine at 5.75. If you scared add a tennie and go to 6" backspace and have shim room. Keep in mind it is the front space you are fighting here. You can only go so far out! Now this will be confusing but I will try to do a easy explanation. Because of the way front and back space are measured, on these cars your working with a 3.75 front space on the front wheels and a 4 1/2" front space on the rear wheels. Front space, like back sapce is measured from the outer rim edge. which is a 1/2" wider then the rim size both front and rear, 1" overall wider.

So the easy way to determine backspace is to deduct 3.25 (3.75 - 1/2" for lip) on the front wheels and 4" (4 1/2" - 1/2" for lip) on the rear wheels no matter what size wheels your going to run. Why? Because even if your running 8" wheels on the back, you still want the wheel profile with the outer edge correct or you get that stupid sucked in look.

Remember each car is slightly different. What fits one does not always fit the next when you pushing it this much! A shim will not hurt a thing. it is much easier to add a $20 shim then rebuild wheels with more backspace.

[trapin]

Frank...that makes sense because my 17's had 4.75 of backspacing on the front which would have left 3.25 for front spacing. I had that baked into my old wheels and they fit beautifully. I will just go with that backspacing again on the front. For the rear it looks like 5.75 is the safe bet.

[Turbo67camaro]

Frank,

In your example for the front, does the 3.75 front space your calculations started with, already include a gap for clearance ?

And, am I correct in assuming that your calculations assume no tire bulge beyond the lip ?

Also, is it standard when ordering wheels to include the 1/2" lip in the front space, and include the 1/2" lip in the back space ? For example, an 18 x 8" wheel, with lip, is 9" wide. So, should the front space plus the back space, equal 9", when communicating the order to a wheel vendor ? If that is the case, it seems simpler to substract 3.75" from 9" to arrive at a backspace of 5.25".

Mike

[rob07002]

Tony, heres the best pic I have of the tucked in look.

[Magntik]

Thanks Rob.

Magntik.....do you have any pics of your rear tire set up? Also....why did you hammer on the wheel well? From what I got from Steevo's thread the adjustments to the wheel well were only needed for the 295. Also, what backspacing did you end up ordering them with and what thickness Skulte Spacer did you have to use?
I used a 1/4 spacer to be "safe".

Frank I and I determined the Pontiac rearend in my '67 Firebird is 1" wider then the '67 Camaro rear. The whole "wide track" thing of the the time. So we were able to adjust the b.s.accordingly, if I recall.
I ended up hammering on the tubs to try to run with out the spacer. My issue was the side to side movement before I added the DSE leafs, rear sway bar and QA1 shocks.
Hard cornering allowed the "top" of the tub to contact the inside edge of the wheel as the body rolled and the rearend moved around "tight corners"...read those circular on ramps to the Highway at speed!!! LOL.
I still have the spacers on and still unfortunately running drums in the back.
25483

[trapin]

Thanks Rob. Yeah, I don't care for how the 275 looks on the 10" wheel. Definitely going 285. I like the tread on those BF Goodrich's though. What model is that?

Magntik, OK...gotcha. That explains the modification then. 5.75 I think is the magic number.

[rob07002]

Thanks Rob. Yeah, I don't care for how the 275 looks on the 10" wheel. Definitely going 285. I like the tread on those BF Goodrich's though. What model is that?

Magntik, OK...gotcha. That explains the modification then. 5.75 I think is the magic number.

Tony, its the Gforce TA KDW-2 (NT). They makes as wide as a 295.

These are for sales as I want the bigger ones.
275/35/18

Make you a deal if your interested.

[Magntik]

Inserted different pics of the wheels. It's pretty obvious in them the way the tire rolls in. 285 or 295's are going to replace these as soon are toasted.:drive2:

[whytry]

Old thread but now its more relevant to what I am trying to do. How do you guys still feel about the 285's in the rear? Any problems or regrets? Also can we see pics and what's your rear brakes and final backspacing?

[XLexusTech]

Old thread but now its more relevant to what I am trying to do. How do you guys still feel about the 285's in the rear? Any problems or regrets? Also can we see pics and what's your rear brakes and final backspacing?
Same question here.... How did this work out....

I am thinking of 285X40X18 on 9.5 ich rim and a 275 40

Not sure if i shoud go 18 or 17 in front....

67 stock sub mini tubs.... lookng for good tuck in rear and balance..