Tire Advice Off-Road Group with 3.92 Rear and 20" rims

[skyhawk42]

He's including the half inch estimated for the lip of the rim. So 9" wide, 0 offset = 4.5" + 0.5" = 5" backspacing.

I was wondering this myself. I have the same wheels(yet to put them on)but mine are 20x10 and they say -18 offset 4.75” backspacing. Now I’m wondering if a 35x12.50 will clear the upper control arm enough?

 

[397STROKER]

-18 will move the tire away from the upper control arm, so you should be good. 19 mm is roughly 3/4" so 18 mm is close to 3/4" further out.

 

[skyhawk42]

-18 will move the tire away from the upper control arm, so you should be good. 19 mm is roughly 3/4" so 18 mm is close to 3/4" further out.

Right, but now it’s a 10” wide wheel instead of a 9” , so did I only gain about a 1/4” or is my math wrong? Or does it work like: stock was +19, mine are -18, so that’s about 1.5” outward, minus the 1/2” for the wheel being wider, so I should be 1” farther from the control arm? Hopefully I get a for sure answer before I spring for tires

 

[Itsslow98]

Right, but now it’s a 10” wide wheel instead of a 9” , so did I only gain about a 1/4” or is my math wrong? Or does it work like: stock was +19, mine are -18, so that’s about 1.5” outward, minus the 1/2” for the wheel being wider, so I should be 1” farther from the control arm? Hopefully I get a for sure answer before I spring for tires

Those wheels will stick put a little over an inch from the fenders. With tires I think they would be flush with the outside of factory tubular running boards just fyi

 

[skyhawk42]

What about control arm clearance if I go with a 35x12.50 tire?

 

[397STROKER]

No matter the width + and - is from the center of the rim. So, your 9" wide rim was +19 which is roughly .75" , zero offset would give you 4.5" on each side of the mounting surface to the inner lip of the rim (where the bead of the tire mounts) add the +19/.75 and you end up with 5.25" and if you say .5" for lip of the rim you have a back space of 5.75" . Now with the 10" wide you are starting at 5" on each side. -18 is .70" roughly yielding 4.3" to the inner lip plus the .5 for the lip gives 4.7" back spacing. 5.75-4.7= 1.05" additional clearance on the inside edge of the rim. With just over an 1" of extra clearance on the inside, I would say you should not have an issue with 35x12.50 tires. as far as the Control arm but I can't say for sure you won't rub or need to trim some to clearance for the turning radius. Also try searching this website for your combination and see if someone has already put 35x12.5 tires on the 20x10 rim with -18 offset.

 

[397STROKER]

forgot to put the link for the website. https://www.customwheeloffset.com/w...ake=Ram&model=1500&drive=4WD&suspension=Stock

 

[skyhawk42]

Thanks for clarifying. I thought I was going to be ok and then started second guessing, so I feel better now. I expected to remove that little mud flap and do some trimming, so I’m ok with that.