Extreme Recon no lift + 37” KM3’s + DuroSpring rear bump stops = no rub

Wheelin Matt

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Installed new fifteen52 traverse wheels with 4.75” back spacing with some 37/12.5/17 KM3’s I had laying around and added the metalcloak durospring rear bump stops to help keep the rear tire out of the fender. Got everything on and took it out on a local flexy trail expecting some rubbing. Although it doesn’t have the flex of a real lift, to my surprise I got no rubbing and it drives and looks amazing! Even lifting wheels (sitting on bumps) no rubbing!
On road it’s even better than the 35” KO2’s but definitely louder. Here’s a few pics. Only bad thing is they gave me chrome lugs instead of black but going to replace those soon

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Mountains2Moab

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Nice! Can you show a picture of the wheel/tire ‘poke’ on that tire set up (0mm offset)?

My white 2023 XR should be here this fall and I was thinking of 37“ KM3 on stock wheels (+12mm offset) and hoping the tread would be flush with outside of the XR fender extender w/o having to purchase some new wheels. Would also add taller rear bump stops (2” total thickness).

Also, would a set of fox shocks let your downward flex improve dramatically, or have to do a bunch of other stuff for that as well?
 
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Wheelin Matt

Wheelin Matt

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Here’s a few pics, does not poke much outside of the flares on these wheels with 4.75” back spacing. Stock wheels are 4.97” back space so it won’t poke at all.
Not sure on the Fox shocks but without more lift I would not want more travel because that would put the tire into the fender. That is the trade off here, low center of gravity and 37’s but less flex. A higher center of gravity will yield much more flex but I’ll need more bump stop or lose the stock fenders and I like the stock fenders
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Mocopo

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Even with a different lift, the bumpstops where they are would stop the up travel. New shocks would just allow more down travel, along with maybe better control arms. Am I thinking of that right?
 
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Wheelin Matt

Wheelin Matt

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Even with a different lift, the bumpstops where they are would stop the up travel. New shocks would just allow more down travel, along with maybe better control arms. Am I thinking of that right?
I’m not an expert on this stuff however if a shock allows more down travel on one side, that means more uptravel on the other side. Would need a lift to allow the axle to travel more….. with lift comes change in geometry for steering and drive shaft angles, which I want to avoid for now
 


Mocopo

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I’m not an expert on this stuff however if a shock allows more down travel on one side, that means more up travel on the other side. Would need a lift to allow the axle to travel more….. with lift comes change in geometry for steering and drive shaft angles, which I want to avoid for now
See that just doesn't make sense to me with the bump stops being static. The logic works if the axle moved on a fulcrum at its center point, but thats not true, even the center of the axle can move up and down. If a bump stop limits up travel of the axle at or near the fender, then regardless of the down travel on the other side, it will always limit the up travel.

So... you're new fulcrum becomes the impacted bump stop at that point. Its probably a simple equation, but for every inch further of down travel on one wheel, you should see a millimeter of up travel on the other, if even, and thats really just the angle of the wheel moving in the wheel well more than anything.

Hoping we get some more opinions on this one, my JLUR-XR arrives from the dealer any day, and until I can afford to put that MC 3.5" GC on it, I want to see what kind of cheap Frankenlift will work to get 37's and some extra flex. If it's as simple as 3/4" spacers and some longer shocks... might be worth it.
 

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You guys are thinking about axle rotation. Which will have a minimal impact on uptravel, but will move the inside edge of the tire inward.

More shock extension (droop) means the axle ends up at more of an angle at max flex. For example, max axle angle is the far right column. The only difference in the lines is the shock.
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Mocopo

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You guys are thinking about axle rotation. Which will have a minimal impact on uptravel, but will move the inside edge of the tire inward.

More shock extension (droop) means the axle ends up at more of an angle at max flex. For example, max axle angle is the far right column. The only difference in the lines is the shock.
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Perfect, this is exactly what I was looking for.

Question though, if I'm reading that right, is it showing an additional almost 3.5" of shock stroke, which would translate to downward flex or a more extreme angle? At what point would we need to be concerned with overextending the XR spring?
 

GATORB8

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Perfect, this is exactly what I was looking for.

Question though, if I'm reading that right, is it showing an additional almost 3.5" of shock stroke, which would translate to downward flex or a more extreme angle? At what point would we need to be concerned with overextending the XR spring?
The two approaches I'd use to confirm would be finding the free length measurement of the springs, and compare that to ride height. Random numbers lets say free length is 20" and the spring is 14" at ride height, should be okay under 6" of available droop.

Second. Throw the jeep on jack stands and pull the lower shock bolt and lower the front axle to the extended length of the potential shocks.
 

Mocopo

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The two approaches I'd use to confirm would be finding the free length measurement of the springs, and compare that to ride height. Random numbers lets say free length is 20" and the spring is 14" at ride height, should be okay under 6" of available droop.

Second. Throw the jeep on jack stands and pull the lower shock bolt and lower the front axle to the extended length of the potential shocks.
Thanks for the advice!
 


kah.mun.rah

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Can you feel the bump stops making contact on bumpy roads?
 

BSchmidt10

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I would assume the bump stops are limiting travel and flex that you would have without them installed correct? Wouldn’t a spring spacer be a better option to continue to allow the full flex of the suspension?

 

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