39-40in tires

[tplee]

sorry for late response, backspacing is 4.75

Sorry, should have asked about offset as well. What other's have done in similar cases will be entirely dependent upon the backspacing and offset of their wheel vs. yours. Just asking the question: "what fits, what hits" will not get you what you need.

Offset describes where the wheel hub mounting surface sits in relation to the wheel width center-line (e.g. if you have an 8.5" wide wheel with 0.0 offset, the wheel hub mounting surface sits in the middle at precisely 4.25". With a negative offset (i.e. -1.0”) the mounting surface moves inward toward the inner lip of the wheel one inch, thereby pushing the wheel and tire outward, giving the vehicle a wider stance. A positive offset obviously does the opposite.

However, this is NOT the same as backspacing. Backspacing describes the distance from the wheel hub mounting surface to the inner lip of the wheel.

Both numbers are needed to determine where the wheel and tire sits in the wheel well.

In general, OEM offset positions the wheel in the most ideal location for stock tire fitment (as well as a myriad of other considerations). OEM bead lock wheels measure 17x8.5 with about a 1.37" (34 mm) offset and 5.91" (150 mm) backspacing (according to the 2017 specs; not sure if same for GEN 1’s, but I THINK they are).

What I would do if I where you is build a mock-up out of wood to check to expected problem areas. You can do this by cutting/stacking wood or other material you can easily shape or cut to size. If you are running stock tires, these are probably actually around 34.5". Assuming your new tire is a true 40" inches fully inflated and mounted to a wheel of you specific width (check this! It’s important!) , you'd need blocking of 0.5 x 5.5", or 2.75". Use HD cargo straps to compress your suspension (if possible) and turn wheel through its cycle, wedging your block in all the tight spaces to check for clearance--or what will undoubtedly be in the case of 40’s, a lack thereof.

 

[SVT_Aaron]

Sorry, should have asked about offset as well. What other's have done in similar cases will be entirely dependent upon the backspacing and offset of their wheel vs. yours. Just asking the question: "what fits, what hits" will not get you what you need.

Offset describes where the wheel hub mounting surface sits in relation to the wheel width center-line (e.g. if you have an 8.5" wide wheel with 0.0 offset, the wheel hub mounting surface sits in the middle at precisely 4.25". With a negative offset (i.e. -1.0”) the mounting surface moves inward toward the inner lip of the wheel one inch, thereby pushing the wheel and tire outward, giving the vehicle a wider stance. A positive offset obviously does the opposite.

However, this is NOT the same as backspacing. Backspacing describes the distance from the wheel hub mounting surface to the inner lip of the wheel.

Both numbers are needed to determine where the wheel and tire sits in the wheel well.

In general, OEM offset positions the wheel in the most ideal location for stock tire fitment (as well as a myriad of other considerations). OEM bead lock wheels measure 17x8.5 with about a 1.37" (34 mm) offset and 5.91" (150 mm) backspacing (according to the 2017 specs; not sure if same for GEN 1’s, but I THINK they are).

What I would do if I where you is build a mock-up out of wood to check to expected problem areas. You can do this by cutting/stacking wood or other material you can easily shape or cut to size. If you are running stock tires, these are probably actually around 34.5". Assuming your new tire is a true 40" inches fully inflated and mounted to a wheel of you specific width (check this! It’s important!) , you'd need blocking of 0.5 x 5.5", or 2.75". Use HD cargo straps to compress your suspension (if possible) and turn wheel through its cycle, wedging your block in all the tight spaces to check for clearance--or what will undoubtedly be in the case of 40’s, a lack thereof.

offset on the method rims that I bought is at 0 with backspacing of 4.75 dims are 17x8.5 tire dims are 37x12.50R17, I had to switch to a 0 offset due to the fact that running the stock rims wouldn't allow me to turn much without the tire hitting the firewall and chewing up the tires. not sure what the specs are on the stock rims to be honest.

 

[tplee]

I have a 2013 raptor with fox 3.0s front/back.
I’m running 37in BFG tires right now, no fiberglass and they work fine.

I purchased the +4 2in fiberglass and want to get bigger tires. Don’t plan on getting any long travel system right now. I want to run a 39 or 40in tire. I’ve looked up answers but can’t seem to find anybody actually doing it. What do I need to do to make it work. Mainly because I like the look, but also want it to function off road as it does now.

Please let me know how to go about this

You'll also definitely need to go to a shorter gear. If 40s, you'll prolly want a 4.88. Might still wanna opt for 4.88s on 39s. Going to 37s myself in the next few weeks and will decide on moving to 4.56s after running them for a while. I've personally run 5.13s on an old Chevy K5 running 38.5" Super Swamper TSLs... But that was also partly due to the anemic bone stock TBI 350 I was running. 400 HP and a 6 speed auto tranny certainly changes things.

Also, didn't realize some of my earlier posts about checking larger tire fitment weren't addressed to the OP.... You'll wanna check out my last post on what I'd do to see if 40s would put you into the firewall on your current wheel...assuming you are staying with your current wheel.

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[timbo33]

What are some suggestions for wheels to go with 40in tires? I’m not sure I understand on all the backspacing and offset stuff.

 

[Chinmasterflex]

offset on the method rims that I bought is at 0 with backspacing of 4.75 dims are 17x8.5 tire dims are 37x12.50R17, I had to switch to a 0 offset due to the fact that running the stock rims wouldn't allow me to turn much without the tire hitting the firewall and chewing up the tires. not sure what the specs are on the stock rims to be honest.

Wouldn't running lower offset make this worse due to increased scrub radius?

 

[timbo33]

Hey guys, so I got my +4.5 fenders mounted up and they are wide!!! Still honestly looks pretty sweet with the stock suspension and 37’s... but, they are making all the necessary work to stuff 40s and they said it’s going to work! As of now I’m not really in the market to go full out long travel, so if I go 40s it’ll look better but If I put a 1.5 in spacer it’ll line up awesome. I’ve read into this some and a lot of guys so no way, but until I can go LT I want it to look good!!
Thoughts please!!

Ps. My “off-road”-ing is mainly rough orchard roads and such, I won’t be baja-ing it until I have all the upgrades I want.