Backspacing needed for Toyo MT 37x13.50?

PalmHarbor · Jun 5, 2013

Hi Guys, I have a 2012 Ram 1500 4x4 Sport Reg cab with a Zone 6" suspension lift. I would like to get the 37x13.50 Toyo MTs but am having trouble finding what offset/backspacing I would need for these to fit. I'm open to either 18" or 20" rims and would think the offset/backspacing would be the same for either size. Some people say 5.0" backspacing is enough and others say I would need 4.5". The Zone website and installation manual both say the largest tire with the lift is 37x12.50 so would there be issues going with a 13.50" wide tire?

One last thing, would a 9" wide rim be big enough or will it look like an over-inflated balloon? The Toyo website says the approved rim width is 8.5 - 11.0" but several people have said that a 9" rim will look bad.

Sharing any thoughts or especially any personal experiences would be greatly appreciated!! Thanks!

BAILEY1 · Jun 5, 2013

I would recommend getting an 18" or 20" with 4.5" of backspacing and -24 or -12 offset. No issue with rubbing on that set up. As far as the width of the wheel..... go with 10, anything smaller is not going to look right IMO.

Now, with the 13.50" wide tire. Every lifted truck I have seen with that set up rubs, and the owner has to do some trimming. This is just what "I" have seen. Maybe someone else on the forum can shed some light on the 13.50" mystery.

PalmHarbor · Jun 7, 2013

Thanks for the reply!

Ya, I did some measuring last night and I can't see how anyone can fit the 13.50 Toyo MT which is actually 14.0" wide without cutting/trimming the corner of the wheel well for the front wheels (the bottom of the wheel well that is part of the bumper assy, not sure what that area is called). It would fit if I never turned the wheel, but would hit with a slight turn. It almost looks like even a 12.50 wouldn't fit but it seems tons of people have that setup so it must.

Something else that I noticed is that I currently only have 3/8" from the edge of the current stock tire to the steering knuckle, so anything wider than the stock tire, which I measured to be 11.0" total width, would have to be pushed outwards. So a 12.50" wide tire means my wheels will need to be pushed out 1.50" (assuming I keep the 3/8" space currently between the tire and knuckle) or am I calculating something incorrectly? Seems lots of people talk about moving their wheels out to fit bigger tires but usually only 0.5-1.0", not 1.50"..?

Current specs:

Wheel: 20x9 Factory Sport Chrome-Clad 5.75" backspacing +19.05mm offset
Tire: 275/60R20 Factory Wrangler HP
Lift: Zone 6" IFS front, 3.0" rear

Backspacing needed for Toyo MT 37x13.50?

PalmHarbor

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BAILEY1

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PalmHarbor

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