Nearest equivalent tire to a 32-11.5-15

Jeepaolic · 03-09-2005, 09:03 PM

Hi I'm putting my 2inch lift(spacers) in 2-3 weeks and I'm considering changing my tires....for now they are 245-75-16 stock rubicon tires and wheels on a rubicon and I would like to keep my moabs and get BF all-terain tires who are the nearest size to a 32-11.5-15 .. there is so many size in 16'' that I'm confused.......and with 32's what about rubbing into the flares ?
I think a 265-75-16 should be ok but what about a 275-70-16?
And will I need a BL to clear those 265-75-16 is I disconect the front sway bar ??
Thanks
Rick

logixrat · 03-09-2005, 09:21 PM

265/75/16 = 31.65 x 10.43 x 16

275/70/16 = 31.15 x 10.82 x 16

To convert metric tire sizes to US simply divide the first number (265 or 275) by 25.4. Doing so will convert from millimeters to inches. This first number is the width.

The next part is to determine the height of the tires w/o the rim. This is called aspect ratio. The equation is simple. Take the first number (265 or 275) and multiply by the second number (75 or 70). The catch is to put a decimal before the 70 or 75. So in actuality, the equation looks more like this: 265 x .75 = 198.75. You now multiply this number by 2 (since there is a top and bottom portion of tire from the rim) and divide by 25.4 to convert to US measurements. Once you have aspect ratio in US measurement, simply add that to the rim size.

Using the 265/75/16 tire size, here is how the calcs should look:

265 / 25.4 = 10.43" wide
265 x .75 = 198.75 x 2 = 397.5 / 25.4 = 15.65 + 16 = 31.65" tall

Getting close to a 32x11.5 would probably be a 285/75/16. It puts you right at 32.83" tall x 11.22" wide. Keep in mind all sizes are nominal, which means that a 32x11.5 tire may actually be 31.3x11.3, or maybe 32.1 x 11.6. Same deal with metric tire sizes. So be sure to look at the manufacturer's actual specs for each tire you are seriously considering to get the exact dimensions.

Jeepaolic · 03-10-2005, 10:35 AM

Thanks for the info but i'm pretty sure a 265-75-16 will clear when discoed but does a 285 will fit whitout rubbing discoed ?? I do not have a BL and not considering it for now .. but could change my mind

Thanks

HandsOn · 03-10-2005, 01:23 PM

That's a good explanation of the process logixrat. Been awhile since I've had to use it, so thanks for the refresher.
Remember too that a typical 32 is not usually a true 32 inches in diameter (some are as small as 30.5 rolling diameter), so your 265/75/16 can actually be larger than a normal 32.
When we first started lifting the old Chevy IFS trucks in '88 we would install 33's in place of the factory supplied 265/75/16's and found that although the 33x12.50x15's were slightly wider, the two tires were virtually the same height in some cases, and some were about a half inch taller overall depending on brand of tire.
I just thought I'd throw that in there because I'd hate to see you lay down some money just to find that your 245's are the same as the 32's you just bought!
How rude!

Paul

blacksheep1 · 03-10-2005, 02:13 PM

logixrat's explanation is good. but i find this convenient as well
http://www.bfgoodrichtires.com/asset...rain_ta_kd.pdf

Jeepaolic · 03-11-2005, 10:43 AM

handson tou where right!
I've mesured a 265-70-16 mounted on a wheel at 30" and I think my stock Mt-R 245-75-16 are 30.5" and I never had any rubbing in flares so I would like to have a real tape mesurement(with the tire on the jeep) from you guys ...from a 265-75-16 ... and from a 285-75-16.....cause I'm pretty sure I could be able to fit a igger tire with my true 2inch coil lift
So will see.
thanks a lot
Rick

Jeepaolic · 03-11-2005, 05:48 PM

really ?? no one could answer this little question ?? :P

hoosier724 · 03-11-2005, 05:55 PM

http://www.dakota-truck.net/TIRECALC/tirecalc.html

logixrat · 03-12-2005, 11:29 AM

Quote:

Originally Posted by Jeepaolic

really ?? no one could answer this little question ?? :P

I think we tried to answer this question. Problem is there is not a firm answer. As myself and HandsOn noted, tire sizes are nominal and not exact. It doesn't matter rather you compare metric or US sized tires, the same rules apply. It is possible a 285/75 would work from one manufacturer and then not work from a different manufacturer.

Clear as mud? My suggestion would be to work with a local tire vendor and tell them you want the biggest tire possible. Try the 285's and see if they rub. If they do have the tire dealer swap them for the next size down. Most dealers have no problems doing this.