37” KO2 fitment

[Turbogoat324]

Hey guys I was wondering if anyone is running 37x12.5r17 kO2’s? I’ve tried searching here and multiple other forums for the actual height of them? Some have said they’re 36.6 but some have said they’re only 35.6. I am running a 1.5” level up front and there’s a bit more fender gap then I like so I was thinking either 35x12.5 or if the 37’s are small enough possibly those. I’m trying to reduce the amount of trimming (if any) that would be needed. Also my wheels are 17x9 + 12. Thanks for any help!

 

[FordraptorHero]

They are 36.3 in diameter, id personally go with the 35s to avoid trimming fenders. The 37s caused my steering rack and pump to prematurely fail .

 

[Turbogoat324]

Thanks for the response. I have a gen 2 so no worries about power steering pump but if they’re 36.3 definitley might have to cut a lot. Awesome thank you!

 

[Wizo]

I think you need a tad more clearance than the 1.5 inch perch up front - maybe the springs instead which would put you at 2.0 inches or the rpg collars at 2.25.

The offset and wheel width are on target so you will be tight but it should work.

 

[Turbogoat324]

I think you need a tad more clearance than the 1.5 inch perch up front - maybe the springs instead which would put you at 2.0 inches or the rpg collars at 2.25.

The offset and wheel width are on target so you will be tight but it should work.

Thanks for the response. Seems like even with the springs I’d need to do some cutting to make sure the 37’s don’t run so I decided I’m going to just do some better quality true 35’s

 

[Ryan C]

I thought I would revive this thread to share some info on the 37/12.5R17 KO2 install I just did on my raptor. I have venomrex 17x9 +12 wheels, and have KHC lower control arm supports that push out the LCA about 1/2" as well (alignment is now done with UCAs). The truck has Fox 3.0s set with 0.75" total lift from stock, and deaver +3s in the back that have sagged a bit due to use and regular weight in the bed.

I did the firewall pinch weld mod (about 14 inches of the weld is beaten back), and then I pushed the liner and modified the inner part of the rear part of the front fender flare to run flat to the firewall mod. I wasn't super aggressive with how much I bent the weld back - I made 1" deep cuts and so gained about 1" of total space. I could have gained maybe another 1/2" had I made deeper cuts or kept going with the hammer. A note on this - I followed the keep it dirty offroad video technique, but had no issue with banging the welds back as they did. It took maybe 10-15 minutes of cutting and banging the pinch welds to get them to where I wanted. 3 hours total for all the work on both sides.

When running the tires through the turning radius there is about 1.5" of clearance on level ground to the rear of the fender flare and liner. Not that this would happen, but it looks like I'd have about 7-8" of vertical up travel at that clearance, so all should be good if I ever compress when turned like that.

I will get out to run the truck through its travel soon, and will report back with my findings. Hopefully I don't have clearance issues at full compression as many have reported with true 37s (these KO2s are 36.3" reported diameter, but actually sit at approximately 35" tall with the sag on the tire when on the truck). Hopefully I don't blow the flares off when testing LOL. I will get +2 fenders if required.

Beyond the smallish 37 size, I chose the KO2s to keep the weight down. I hope this reduces maintenance/issues compared to a heavier 37 like a KM3 or the offerings from Toyo, Falken or Nitto.

I think the truck looks better too, for whatever that's worth, but am really hoping for some better offroad performance with better rollover and cushion from the slightly larger tires.

Cheers

Ryan

 

[Ryan C]

Additional info that may be helpful: I measured the 37 spare, inflated to 34 psi on a 9" rim, not on the truck, and its just under 36".

 

[snt505]

Hows your rear look? My 37s (and another member on here I believe) caught the front part of the rear fender flare. I caught on the bolt head and broke it off. It's close though and tolerance stack might give you more clearance. Something to think about.

 

[Ryan C]

Interesting on my truck, the rear fender flare is closer to the tire, on the rear part of that flare. There is a difference of more than 1/2" between the two ends. The others side of the truck, its more even, but still 1/4" different. So ya, lots of variance there, and I'll just have to see how it goes. Thanks for the heads up

 

[Ryan C]

So I took the truck out on an 80+ km offroad test tonight, on a road I know well and had driven earlier this week (also at night). So far, there was only very minor rubbing at true full compression (solid jump at 80km, with definite bottom out) on one side of the front fender flare. I think I will monitor for now, before doing any further trimming.

I have to also report that the truck was subjectively and objectively much more capable. More ground clearance for compressions, large dips and water bars; better rollover on small and big holes; more stability; and generally, all resulting in speeds of 10% more than I usually go on that particular road. I was really impressed. Makes me want true 37s LOL.

I also did over 100km of highway and measured mileage. It was only marginally worse at 0.5-1.0 L/100km on the computer. It also didn't feel like there was a significant drop in acceleration or braking. This is likely because the 37KO2s are only a few pounds heavier than the stockers.

Stoked