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73-87 Chevy _ GMC Trucks => Wheels & Tires => Topic started by: cwilson jr on September 19, 2007, 08:44:55 pm

Title: standard vs. metric tire sizes?
Post by: cwilson jr on September 19, 2007, 08:44:55 pm
could someone please explain how i figure what standard sizes would work on my pickup  if they are larger.  i never did figure out how.  i have an 85 k10 with stock lift and 15" rally wheels all the way around.  i believe they're 15x7?  i basically want the largest and widest tires i can without any rubbing, and clearance issues for hauling.  something to fill out the wheel wells a little better.  i want to keep my stock wheels at the moment along with my stock lift.  someone offered me a set of 35's, but again i'm not sure of the standard sizes.
Title: Re: standard vs. metric tire sizes?
Post by: Captkaos on September 19, 2007, 09:54:03 pm
you can covert to metric by taking the following 285x75x15
285 is the section width (not tread width)
75 is the aspect ratio - percentage of the section width equals side height
15 is the rim diameter.

If you take 285 divided by 25.4 = 11.2" that is the section width in inches
Multiply 11.2 x .75 (aspect ratio) = 8.4"
Multiply 8.4 x 2 (top and bottom of sides) = 16.8"
Add the 15" to the 16.8 = 31.8" overall diameter from top to bottom.

As for a 35" tire, it will NEVER clear a stock truck.  You will be hard pressed to get 33's on there without hitting the rear of the fenders.  I have used 31x10.50's on a stock truck and they didn't rub.
Title: Re: standard vs. metric tire sizes?
Post by: bfofish on September 19, 2007, 10:57:55 pm
I have run 32x11.5R15 on stock suspension and stock ralleys without a problem
32's are a little hard to find,not everyone makes them
I had BFGoodrich mud terrains
They do make the all terrains in 32's
Title: Re: standard vs. metric tire sizes?
Post by: cwilson jr on September 23, 2007, 11:06:03 pm
looks like i can pick up a decent set of 32x11.5's.  do these still have enough room to haul a load in the back occasionally without rubbing issues?
Title: Re: standard vs. metric tire sizes?
Post by: 85MudMonster on October 23, 2007, 11:17:55 pm
I've got Maxxis BuckShot 33x12.50R15's on my 85 K10 they are fine, I've had no problems, but then the truck did come with 31's from the factory...

Dan