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Tyre vs. rim width
http://classiccamaroclub.mfatw.com/viewtopic.php?f=9&t=5192		 Page 1 of 1
Author:  78 Camaro [Mon Feb 27, 2017 9:57 am ]
Post subject:  Tyre vs. rim width
Just wondered what the largest tyres are that could fit onto an 8" wide rim? Not so much wheel arch space (that would be useful too), more about the tyre vs. rim. I've seen everything on forums from max 235 to 315. Truck (4x4) guys seem to run 12.5" (315's) on 8" rims and use them daily that way. I run 255's and have a pair with 275's as well and it looks normal.
Author:  Jamieg285 [Mon Feb 27, 2017 1:19 pm ]
Post subject:  Re: Tyre vs. rim width
Depends on whether you are going with what fits properly and what fits. ;)

Most tyres will have specs on what size wheels they willl fit, so after you've chosen your tyre look for the specs to see what the widest recommended size for an 8" rim is.

Of course you can go wider, but the tyre will be bending outside of it's intended shape. This may or may not have consequences.

The other thing to consider is clearance. A wider tyre will move the tyre towards the body and the fender edges. If you've got tight clearance already, going wider withouth changing the offset of the wheel may give you problems.


I used to run 3rd gen wheels on mine, which from memory were 8", and I got occasional rub on the passenger rear with 235s. Regadless of that, I personally wouldn't go over 245 without going for a wider wheel.
Author:  78 Camaro [Mon Feb 27, 2017 3:07 pm ]
Post subject:  Re: Tyre vs. rim width
Quote:
Depends on whether you are going with what fits properly and what fits. ;)
I like that :)

I run 255 60 15 currently on what appears to be an 8" rim. I run these front and back and even with the car lowered, they fit nicely and don't rub (wheel arch lip measures 26" from the ground). If anything, the rear wheels are too tucked in as it looks broader on the front and narrower in the back.

What i've done is got some 12" wide, 27" tall 15's; Goodyear Eagle NASCAR tyres to use at track days. They are the same height as the 255 60 15's (27") and it's only the section width (12") that differs (works out to 305). In other words it's a 305 50 15. From what i've read, it will fit in the rear arches as people have gone up to 315 width. So it's really a case of figuring out rim width and backspacing. I have a pair of slot mags which are 8.5" wide but the backspacing is 3.75" so i have a feeling these may stick out too far and have unused space on the inside. NASCAR rims are 9.5" wide so running an 8.5" rim would be quite close. Interestingly the tread width is 11" and the sidewall width is what brings it out to 12".

Ideally i would run a pair of slotmags, 9" - 9.5" with 5" - 5.5" backspacing. Can't seem to find any. If anyone has any...
I looked at Cragar D Windows but they seemed to have disappeared from everywhere. They are a steel wheel and come in many sizes, but Northants tyres are the only place that seem to have them and they only have an 8" with 4" or 3.75" backspace.
Author:  78 Camaro [Mon Feb 27, 2017 8:31 pm ]
Post subject:  Re: Tyre vs. rim width
Doing some more research and came across a Mopar forum. They tend to be running 295's on 8" rims. I'm thinking 305 on 8" / 8.5" may work?
http://board.moparts.org/ubbthreads/ubb ... 632/2.html

Had a quick look on Mickey Thompsons site and they show a 12.5" tyre to mount between 8" and 11" wide rim. (section width 13" tread width 10.4") http://www.mickeythompsontires.com/stre ... tsman-pro/
Author:  chevy-stu [Tue Feb 28, 2017 12:57 am ]
Post subject:  Re: Tyre vs. rim width
Max I'd run on an 8" rim is about 255.... anything bigger and they'll be ballooning a alot. 15" wheels gives a bit more scope as the side wall is still pretty chunky.

The lower the profile the more important the tyre width is matched to the wheel, as there's obviously less sidewall to compensate.
I'm on 18" rims with 245 on a 8.5" up front.. 295 on 10" rear.
Author:  78 Camaro [Tue Feb 28, 2017 8:58 pm ]
Post subject:  Re: Tyre vs. rim width
Cheers Stu, is your ride height the same on Blue as it was on the old one? Wondered if you have any tire rub issues as i remember if you had a person in the back it would sometimes rub on bigger bumps. Do you remember what the offset is for the rims?

Found a vid of a guy with 295 50 15's on 8.5" rims, so it seems the 305's would be even more exaggerated on the 8.5's that i have. Looks like i'll be searching for 9, 9.5 or 10's.

https://www.youtube.com/watch?v=jqFB2lYzUmE
Author:  chevy-stu [Thu Mar 02, 2017 6:21 pm ]
Post subject:  Re: Tyre vs. rim width
Quote:
Cheers Stu, is your ride height the same on Blue as it was on the old one? Wondered if you have any tire rub issues as i remember if you had a person in the back it would sometimes rub on bigger bumps. Do you remember what the offset is for the rims?
Blue one is same at rear, as same leafs, but front is fractionally up with some 1/2" spacers, as it used to hit the headers constantly.
Rears do rub on very big dips, rear disc conversion moves the wheels out about 3/8 inch too which doesn't help, but I'm gonna go down to 285 width on next tyres, to cure this..
Can't remember wheel offset, 13 or 19mm maybe
Author:  Jamieg285 [Fri Mar 03, 2017 12:31 pm ]
Post subject:  Re: Tyre vs. rim width
Is that a rub on the inner side, on the seatbelt hump, or the outer on the fender lip?

I used to get inner rub with enthusiatic driving on roundabouts where the tyre rolls over.
Author:  chevy-stu [Fri Mar 03, 2017 5:30 pm ]
Post subject:  Re: Tyre vs. rim width
It used to be on inside on the old pink car, but just the insides of the outer arch on the new blue car if that makes sense..
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