35x12.5x15 on 15x8 ralleys...problems?

[orangeuavol]

What are the drawbacks of mounting 35x12.5x15's on 15x8 wheels?

[Destructo]

They will work fine, I run 33x12.5" tires on 15x8, I just have to run lower air pressure in the rear, but run 35 psi in the front. You can run lower air pressure and won't be as likely to blow a bead off-road.

[Stocker]

I know plenty of guys run 12.50 tires on 8" rims, and I'm not trying to stir anyone up, but...

It's my understanding, and I think most tire people will agree, that a 10" rim width (or 9.75 with 16.5 rims) is the recommended size for a 12.50 tire. A narrower rim will squeeze the sidewalls somewhat and may cause the tread to wear faster in the center. You can ease the situation a bit by running lower air pressure, but that increases fuel consumption. A rim that is too wide or too narrow will also change the handling characteristics of the tire by changing the way the sidewalls flex. An old rule of thumb is the rim width should roughly match the tread width. Some tire companies' websites have recommendations - BFG in particular gives an accepted range of rims for each tire, and their recommended width.

just my .02 :p

[alf4444]

I run an 8" because when you air down on the trail its harder to lose the bead both ways have their advantages and disadvantages.

[2wdBlazer]

I have heard 8 inches is the preferred rim for 12.50 tires. I run 10 inches on a 15.50 tire.

[Stocker]

Originally Posted by alf4444

I run an 8" because when you air down on the trail its harder to lose the bead both ways have their advantages and disadvantages.

Very true, and of course the safety lip inside the bead on 15" rims helps too. I never understood why 16.5" rims don't have that feature...

[Destructo]

If I wanted to spend the money to buy new wheels I would buy 15x10s for my 12.5s just because I mostly drive on the street, but then they would rub my front fenders and I would need a couple inches of lift to clear them.

For all street driving I would put them on 15x10s, but if you use it off-road a good bit I would rather not have to worry so much about losing a bead, most tire manufacturers recommend a 8.5-10" rim for 12.5" wide tires.

15.5" super swampers is another thing, their designed to run on 10" wide wheels. You couldn't get away with running a smaller 12.5" tire on a 7" wheel I don't think.

[orangeuavol]

Thanks for the info guys.

[poff]

I run 33 x 12.50s on 16.5 x 8s (7.75") with no problems. Off-road aired down and on road. I run the full 50 PSI on the road and the wear pretty evenly. The rear locker seems to wear the rear tires faster than the fronts though.

[JIMs70GMC]

Search my post I posted pics of 33/12.5s mounted on 16.5x9.75 and 16.5x8.25 in a side by side comparison earlier this year. Not much difference.

[Stano]

I run 35x12.50x15's on 10 inch rims. I pull trailers and offroad out of necessity sometimes. Can't afford to tear the truck up for fun ya know. LOL My truck handles really well and is responsive. I drive it everyday and have had excellent treadwear at 35psi. I did mess my tread up on the front tires cause my frontend was out of alignment so I rotated from front to rear after I fixed the problem and no probs after that. This is on my frankenstein truck. 83/82 body on a 74 frame with 79 suburban running gear 3 inch body lift and 2 inches from modified 3/4 ton springs front and rear for 5 inches total lift.

[4x4Poet]

Originally Posted by Stocker

I know plenty of guys run 12.50 tires on 8" rims, and I'm not trying to stir anyone up, but...

It's my understanding, and I think most tire people will agree, that a 10" rim width (or 9.75 with 16.5 rims) is the recommended size for a 12.50 tire. A narrower rim will squeeze the sidewalls somewhat and may cause the tread to wear faster in the center. You can ease the situation a bit by running lower air pressure, but that increases fuel consumption. A rim that is too wide or too narrow will also change the handling characteristics of the tire by changing the way the sidewalls flex. An old rule of thumb is the rim width should roughly match the tread width. Some tire companies' websites have recommendations - BFG in particular gives an accepted range of rims for each tire, and their recommended width.

just my .02 :p

I have variously owned at least 4 of BFG's 12.50 MTs near continuously for three decades. BFG recommends 8.5-10" rims for all their 12.50 tires. The rest is true only for bias tires.

Radials conform to the road much, much better than bias, hence the infamous radial "side bulge." I highly recommend a 12.50 radial off-road tire be run on 8.5" rims, never 10" unless solely for looks. On road, run the radial at max pressure, even if 50psi, for best highway mileage, crisp handling, less heat generation, and less tire wear. Yes, less. I'm only talking radials, here. Bias 12.50 tires at max pressure on a light truck would likely crown wear. But radials will conform to the road surface, even at max pressure.

You'll get less shoulder lug wear because 12.50s @max press will have less "roll-under" during cornering & on mountain curves. The reduction in heat that max press enables will also extend tire life as cool tires are easier on belts/cords/mold "glue", etc. Running radials at max press is also great for towing stability.

Currently, I have BFG's 33x12.50R-15 MTs on 8.5" rims and run them on road @ max press (50psi) even in snow, though then I'm in 4wd. No uneven wear after 10k+ miles. In fact I can't see much wear. Surprising, since the MTs are soft compound Moab Editions. My 2¢.

[orangeuavol]

much appreciated.