Wheel and tire sizing help please

[lawlorj]

I'm going to pull the trigger on some wheels for my 1968 Camaro very soon. In the wheel and tire database "Jonathan" has the exact wheel and tire dimensions I want to go with, 17x8 4.5" BS 235/45/17 fronts, 17x9 5" BS 275/40/17 rears. That just so happens to be the dimensions of the wheels I want. I made my own measurements on my car and it looks like they will fit. However, I am a bit hesitant to go with that combo because multiple sources are saying that the front and rear backspacing is not correct for a 68. This is making me second guess my measurements. So if there is anyone else running that combo that can chime in it would be greatly appreciated.


Car Specs:
68 Camaro
Front: stock control arms, hotckis 2" lowering springs, C5 brakes, Tall upper ball joints and tie rod ends.
Rear: Currently all stock but going to lowered multi leafs and LS1 brakes on a 8.5" 10 bolt

Thanks!

[Steve 69 Bird]

I'm working tire and wheel combos myself right now. My 68 Bird is lowered front and rear. The issue is the outer edge of the tires are directly under the wheel well opening outer edge. With the car lowered there is not much room for up and down wheel travle under the lip. From what I have fit so far the 17x8 with 4.5 backspacing with 245/45 tires looks ok for the front but not the rear. With the the lowered Hotchkiss springs the outer inch of the tires are under the quarter panel opening fender lip. Tires have plenty of room to move inboard (I have a rear shock inboard relocation kit).I should have rolled the lips when I replaced the quarters. I'm looking at ordering a pair of custom 17x9 Torque Thrust II's with a 6" backspace for the rear.

[Buryingthesun]

will 275/40R17 tires fit in the rear on a stock body car?

[lawlorj]

From all I read 275 is the go to size for first gens. Any larger and you run into rubbing issues. I haven't fit a set myself but according to my own measuring they will fit. Backspacing on the wheels has to be bang on.

I went out and measured again and I know what you mean about the fender lip Steve. It is tough to tell since I am not lowered in the back yet. 5" BS in the back is probably not enough. With the drums it might be ok, but add the thickness of a disk and your running into trouble. For me I think 5.25" would be ideal without rubbing on the inside, again this is a 9" rim. I still might have to make fender modifications but I don't mind that. 6" of BS seems like way to much, even at 5.5" I would probably rub the inner fender.

As for the front I am just as stuck. At 4.5" BS I might have some fender clearance issues. If I go to 4.75" the fender clearance is better but I am coming close to the tie rod end, within a 1/4" or less. How much clearance is ideal between the tie rod end and the wheel/tire?