Max Tire Size

Rob D

Rob D

Get R' Done
Joined
Mar 10, 2007
Messages
421
Hey guys,

2006 F350 - I need new tires, and was wondering what the biggest size you can fit on a stock truck w/o rubbing. When I checked @ a local store a few months back I believe they told me they thought I might be able to fit in a 35"....thanks.
 
If you willing to do some trimming 37's.....lol


these were 36's...but 37's would've easily fit

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Ehhh I don't wana mess around with trimming...

Anybody running the MT Baja Radial ATZs?

Tanks - did you have the leveling kit?
 
Well I am going to order some this week...so everyone can be expecting a real nice new burnout video soon :evil
 
6.0kingranch that size is only 34.36" - you sure you don't have 18s??
 
I have a 2007 F350 4x4 with "LT275/70R18E BSW ALL TERRAIN" wheel/tire combo from factory. Can I move up to 20" rims with a take offs swap from some other newer superduty with factory tires? Is there a max "275" number that I can't go over with stock setup, is that number 305?

Thanks for the help.
 
The way tire size works are as follows:

First # (275) = tire width in mm
2nd # (70) = sidewall height as a % of tire width ( 70% of 375 = 192.5mm)
Last # = R18 rim size

To find out overall dimension:
(192.5)x2 since two side walls(bottom and top) = 385mm
385mm/25.4 = 15.16 (there are 25.4 mm in an inch)
15.16 + 18 = 33.16" overall


Therefore you can mess around with whatever wheel/tire combo you want...as you increase your wheel size or tire width - the 2cnd # or side wall height % will decrease in order to maintain stock proportions. In essence all your doing when increasing rim size w/o tire size is making a lower profile tire/wheel setup. If you want a 20" rim and the same size overall tire dims youd be looking at something like:

275/60R20s = 32.99"

if you want to go wider - your second number will decrease even more seeing as how it is a function of the first:

315/50R20 = 32.4"
315/55R20 = 33.64 etc....

I believe I have 315/70 R18s on my truck with no leveling kit stock which = 35.36"

I have no rubbing and didn't need to trim anything.
 
I run 325/60R18 on 18x8.5 Weld wheels under my stock height 07.


Now that I swapped to 7000lb coils (450/550 coils) I picked up a little height and may go 305/70R18 next time.
 
If you have a 2005 and up F350 with a leveling kit you can have 35's on it. We have three turcks near me that runt hat setup. If your a 250 and lower you should beable to get 33's on the stock truck just fine.
 
325/60R18 way to go!

on our 17's, we just run 285/70R17's.
 
The wheel offset will throw you a little curveball though. And if the wheels have different curves to the sidewall. The offset changes your pivot center and the different manufacturers idea of a size doesn't always mean they are the same dimension diagonally.
 
My 325-60r18 Xterrains on 18x8.5 welds look a little off with the 4" lift and do hit the springs. Sounds way worse inside than it is. They would fit without a lift . I like the width , but swap them out for winter because they SUCK on ice.
 
PSDPlayer said:
The wheel offset will throw you a little curveball though. And if the wheels have different curves to the sidewall. The offset changes your pivot center and the different manufacturers idea of a size doesn't always mean they are the same dimension diagonally.
Click to expand...

Thanks... I was just going to make that point... you can order 3 different tires, all the same size, 325/70/18 (or whatever) and I guarantee you all three will be different. I don't know who's yardstick they use to make up the tires, but the numbers sure as hell don't match anything I can see. I run into this all the time with my car tires... might want to actually measure them first, or go with a specific tire that someone you trust is using that you knows will fit.
 
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