I've seen a lot of discussion regarding a 17X9.5 rim, typically being at 5.5". What does anyone recommend for a 17X9? Is 5" BS enough, or should I got to 5.25". Planning on 275/40s or 265/40s. It's for a 69 camaro with Hotchkis 2" drop front/rear. Thanks for your help.

I would go with 5.25. Some guys go with 5 and 3/8s even. If there is error it's better if it's too much backspace (you can always resort to a small spacer if you have to) than not enough.

I have 17x9 with 5.25"bs (255/45 though) on a 67 and fits perfect....I dont think the 275/40's would work for me without rubbing.

You should measure your car for an acceptable backspace. For example, If I were to use a 5 1/2" bs on my car, yeah the wheel would fit but by the time you factor in tire bulge I would only have about a 1/4" clearance. From what I have read that will surely give you problems.

I am going through the same thing right now and would actually be more interested in finding out what an acceptable amount of tire to inner wheelhouse clearance would be. This way you could tuck the tires in as tight as possible and work your way out for the max width.

As I said I am measuring for new wheels and tires right now and would like to hear what others have experienced as far as rub, no rub tolerances.

Information such as suspension design and setup should also be included as this is a major contributing factor.

Chris

Good words above.
Would need to add "Measure both sides!"
MANY of these cars don't have the axles exaclty centered under them. Some are off by 3/4" from one side to the other!

Measure the rim width and backspace of the tires you have. Then figure it as if the larger size you'd like to buy is on those same rims. Would they clear?
Then do a lil ciphering to figure out the proper backspace on the new wider rims.

The centerline of a 7", 3 1/2" backspace rim is the same spot as an 8" 4" bs rim, right?
The centerline of a 7", 4" bs rim is the same spot as an 8", 4 1/2" backspace rim.
So in both cases, a 2" wider tre would exactly split those 2" over the centerline, 1" bigger to the inside, 1" to the outside.
Do you have room?

Whenever you go wider then the "norm", you have to measure your car very accurately.

If I reach my hand over the back tires on my 68, I have 2 1/2 "fingers" between the sidewall bulge and the inner fender on the pass side, 2 3/4 fingers on the drivers side. That is more than enough room, and when I wear out these tires (255's) I'm gonna put a set of 275's on these same rims. 2 1/2 fingers is about 2 inches. The 275's are 20mm wider, that's less than an inch, split evenly inside to outside. My inside clearance will be about 1 1/2". I think it will work, tho I may have to be gentle when turning into driveways and other manuevers that will only compress one side of the back suspension at a time.

I run 17x9 rim with 5 inch backspace and a 275 tire. I have no problems with the set up.

I run 17x9 rim with 5 inch backspace and a 275 tire. I have no problems with the set up.

i run the same, but on a 69, the wheel lips must be rolled.

Thanks for everyone's help. I think 5.25 and 275s is what I'll go with, after I measure to be sure.

The centerline of a 7", 3 1/2" backspace rim is the same spot as an 8" 4" bs rim, right?
The centerline of a 7", 4" bs rim is the same spot as an 8", 4 1/2" backspace rim.
So in both cases, a 2" wider tre would exactly split those 2" over the centerline, 1" bigger to the inside, 1" to the outside.
Do you have room?

Whenever you go wider then the "norm", you have to measure your car very accurately.


Just to add to what Jim mentioned above, "backspace" is measured from the inner wheel lip to the wheel mating surface.
This measurement is related to "offset" but isn't the same. Offset is the distance from the centerline of the wheel (and installed tire) to the wheel mating surface.
The inner wheel lip thickness is generally considered to be about 1/2". So a to get a 7" wheel that is centered on the wheel mating surface (0 offset) you would need 4" backspace (or very near that depending on the manufacturer).
Be sure and measure your car.