Rim offset and backspacing to fit 37s

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Stuffpower

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For those that have done it. What wheel size, backspacing and offset work to clear 37s without rubbing?
 

olyelr

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Well, the diameter of the wheel really has absolutely no bearing as far as clearing 37’s goes. Could be a 17” wheel or a 24” and your fenders wont care regardless.

AEV wheels are about the perfect offset/backspacing for clearing 37’s, which are a 17x8.5 with a positive offset of 27 and backspacing of 5.8”. Depending on the height of truck and the 37” tires (we all know those very quite a bit), there still may need to be some minor trimming performed.
 

SeppW

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Min dia is 17 in. any smaller and caliper clearance issues. Aftermarket wheel offset is somewhere between +25-+27 to keep the tire/wheel under the fender/flares. (- ) offset and your tire will extend beyond the fender/flare, which opens up another can of worms. I would expect trimming of wheel well liner, pinch weld/seam, and possibly still rub the control arm or sway bar or both. AEV and CJC Offroad have Ram HD-specific wheels for the platform, the latter specifically for the 37 in tire. Can run 37s on factory wheels, but rubbing is very likely, and trimming is almost certainly mandatory. Like everything else on these trucks, YMMV. Plenty of info on this forum on what works, what won't, and how some require no trimming and others don't.

I'm running AEV Salta on 35 Toyo C/Ts. Primarily because I didn't won't to regear and do occasionally haul/tow heavy. But that is another story with many different versions. If you're not regearing and going to 37s, you'll need to recalibrate with AlphaOBD, or other device, to correct speedo and stop the trans from hunting gears. I would assume the 8-speed trans needs the same recalibration for the speedo, but I have read the 8-speed can handle 37s just fine. I can't say for sure though, I have 6-speed.
 
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retired

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Min dia is 17 in. any smaller and caliper clearance issues. Aftermarket wheel offset is somewhere between +25-+27 to keep the tire/wheel under the fender/flares. Any more + offset, and your tire will extend beyond the fender/flare, which opens up another can of worms. I would expect trimming of wheel well liner, pinch weld/seam, and possibly still rub the control arm or sway bar or both. AEV and CJC Offroad have Ram HD-specific wheels for the platform, the latter specifically for the 37 in tire. Can run 37s on factory wheels, but rubbing is very likely, and trimming is almost certainly mandatory. Like everything else on these trucks, YMMV. Plenty of info on this forum on what works, what won't, and how some require no trimming and others don't.

I'm running AEV Salta on 35 Toyo C/Ts. Primarily because I didn't won't to regear and do occasionally haul/tow heavy. But that is another story with many different versions. If you're not regearing and going to 37s, you'll need to recalibrate with AlphaOBD, or other device, to correct speedo and stop the trans from hunting gears. I would assume the 8-speed trans needs the same recalibration for the speedo, but I have read the 8-speed can handle 37s just fine. I can't say for sure though, I have 6-speed.
I have 2020 and also run Toyo RT 35's on AEV wheels and really wish I would have went with 37's. even with 35's on a 8 speed it is important to calibrate your speedo to ensure proper shift points.
 

olyelr

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Min dia is 17 in. any smaller and caliper clearance issues. Aftermarket wheel offset is somewhere between +25-+27 to keep the tire/wheel under the fender/flares. Any more + offset, and your tire will extend beyond the fender/flare, which opens up another can of worms.
Any more + offset will push the wheel in toward the vehicle, not outside of it.
 

Rick Ram-jet

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Getting back to the op`s question regarding offset, I personally agree that the AEV rims have the perfect offset for these Ram trucks, AEV rims are specifically designed for the HD Rams as opposed to a one size fit many approach of some other brands! That being said there are many other good choices available, I believe the rule of thumb is staying in the +18 thru +25 offset range for the best overall fit.
 

olyelr

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I think -24 is as wide of an offset you can go without rubbing with 37s, I know for a fact -19 you can do it
Its a lot different with the solid axle 2500/3500 platform….completely different then the half tons.
 

bmhenry

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need to know the year.. assuming 2021.. From the Don Thuren Bible..

Wheel And Tire Fitment For The 2013+ 3500, 2014+ 2500 Trucks Including Power Wagon: 0-3" Lift

At 57mm, the stock wheel setup for the 2013+ 3500 and 2014+ 2500 will require a +18 to +25 millimeter offset range in order to achieve proper fitment. The same goes for the Power Wagon which in stock form has a +42 to +57 millimeter wheel offset.

The +18mm to +25mm offset will give the best overall clearance for tire and wheel combinations once you install a 0 - 3 inch lift. The above-mentioned platforms clear stock tire setups better than the Pre-2013 models. Most trucks come from the dealer with 34 inch diameter tire sizes, therefore fitting 35 inch tires are out of the question...mostly.

A 35 x 12.5 tire size wrapped around stock rims will fit but will also rub on the radius arms. The same goes for a 37 x 12.5 inch tire size on a stock setup; however, it’s guaranteed that the turning radius will suffer dramatically coupled with rubbing on the sway bar and radius arm.

Applying a +18mm offset to a set of aftermarket wheels and a 37 x 12.5 inch tire diameter fits nicely with zero contact on the radius arm or sway bar. If it rubs at all through the vertical range of motion it’ll be very slight.
 

22hemi13

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Not on a 2500 with 37s…unless you trim a bunch lol
Or have a stupid amount of lift.
Yep. I had to cut a lot to clear my 37s on -19 when I went to 39s I cleared even more. I did it good cause I’m on 40s now and didn’t cut anymore. But switched from a -19 wheel to a 0 offset wheel.
 

Nick@GotExhaust

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Great info here

 

62Blazer

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Search for CJC Offroad on the website as they have several videos of running 37's on the Ram's and explain how the wheel offset affects it.
 

olyelr

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I should clarify.. it is a power wagon.
Unless you go with a full on “lift” with bumpstop drops etc., there really is no difference.

The factory fenders fit 37’s pretty much perfectly. It all depends on you wheels tho…high offset and backspacing can make a set of 33’s rub…
 
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