Rubbing post axle relocate

Let me start with my set up in rear... TSB springs, Icon 3 leaf add a leaf, overload removed, OME shocks. I have 285/70r17 Nitto Trail Grapplers (33.15"x11.87") on 17x9 ATX Artillery wheels, 4.5" backspace.

I found that under full compression, the rear spring goes into negative arch. This causes the rear wheels to move forward at max compression as the ends of the leaf springs get closer together. The result was my tires crashing into my rear wheel well in front, pulling off my fender flare and pulling off some fender liner.

To solve this I installed an axle relocation plate. This plate has two holes and is reversible. One hole is 3/4" spacing and the other is 1". You use tbe 3/4" spacing... 1" can cause you to rub tje rear of the rear wheel well instead of the front. I bought mine from Allpro but they are available anywhere. This is a 3/8" thick plate and acts as a 3/8" lift block. There is no getting around the fact it lifts you 3/8".

I also installed the Allpro Ubolt lift kit. I ordered the version that has threaded holes for Timbren bumpstops (its an upcharge) and comes with attachment hardware for the bump. I modified my factory bumpstop to fit so as to not lose any more uptravel than necessary.

Since the top plate on the flip kit is so thick and there is a 3/8" lift block, raising the bumpstop from the rear axle, the tires cannot contact the top lip of the fender flare. Yes these mods removed 1/2" uptravel... but that is unavoidable. The tire stays about a pinky's width from touching the rear fender flare under compression. It initially looked like there was a mile of room at the front of the rear fender under compression.

What I found was this... even after the axle relocate and Ubolt flip and even though the clearance looked excessive in front of the rear tires (rear tires not centered in wheel well at ride height) I was still getting some rubbing of the front of the rear wheel well.

What caused it? When the truck is kicked over 15-30 degrees to one side, lointed up a 30-45 degree hill, and the rear tire is at its max compression, resting on its bump stop, there is enough give in the springs to allow the compressed side of the axle to move forward. Wben you gas it in that position you get axle wrap, which pulls the axle even a little more forward and the tire lugs start tearing at the fender flare. Now, with the revised bump location removing 1/2" of uptravel and the axle relocated 3/4" to the rear the needed trimming is minor (remove about 1/2" from the inside corner at the front of the rear fender) BUT it demonstrates that a 3/4" axle relocation plate is MANDATORY if you wheel hard and dont have longer bumps or a spring kit that offsets the axle to the rear. I will try to include pics of my compression.

 

Here is an example of compression post mods. Before the tire would compress 1/2" higher and the wheel would be over 3/4" more forward because in addition to the 3/4" relocation, the added compression makes the axle move even further forward in the wheel well. In the pic, gassing it as I attempted to go up the hill in front of the truck caused the axle to wrap and grab the inner flare lip. Before it tore off the flare and pulled off the liner too. Trimming alone is NOT enough at 33+" tires that are 11.5" wide or wider. You MUST relocate the axle, reduce compression range of movement with longer bumps, or both.

 

Excellent post. Thanks.

 

I had read Dakars moved it forward. Either way, I'm still going to wait until I experience rubbing before adding a relocation plate.

 

The distance between the axle and the ends of the bumpstops determines how high the tires get on compression. A lift block, longer bump stops, or a thicker spring pack can (a Dakar with all leaves is very thick) all are a part of determining that distance. If you lack the proper distance you wheels will move forward too much as the spring goes into negative arch.

 

None of these made me rub either... it is only when compressed, leaned over, AND pointed up a steep incline. There has to be enough weight pushing the truck back to make the springs give.

 

You got a measurement you can post for reference from the top of the bumpstop to the frame or the from the axle to the end of the stop?

 

Spring perch to end of bump is the key measurement to determine up travel. Will measure tonight and post.

 

My spring perch to top of bump appears to be about 6". This breaks down to 2 5/8" spring perch to the top of the axle relocate plate. That includes 3/8" axle relocate plate, the spring pack, and the top plate. The factory bump appears to be 3 3/8" long... that is approximate where the 2 5/8" distance from spring perch to the bottom of the bumpstop is exact.

If someone could measure Dakars it would be great. I was only at like 2" with factory bump location before the ubolt flip kit and axle relocate plate. That was with TSB plus Icon 3 leaf with overload removed.

I think the lesson at the end of this will be thin leaf packs may be dangerous with large tires due to excessive uptravel.

 

Believe you meant to say Ubolt flip kit plate there.

With Dakars and no AAL I measured 3" from top of spring perch to the top of the ubolt flip kit. Keep in mind, I dont have the extra thickness from the axle relocation plate. I measure my factory bumpstop at 2 7/8", so one of us is incorrect in the bumpstop measurement. My total measurement was 5 7/8" from top of spring perch to top of the bumpstop.

At this point, my measurements don't mean much and are only a reference point, since I haven't experienced any rubbing yet.

 

Yes I meant ubolt flip plate. And while the springs, plates are flat and flush/vertical. The bump is way harder for me to measure accurately. I can see why people dont rub as much with Dakar springs though... those fractions of an inch make all the difference.

 

After fully testing out my rear suspension this past week in the mountains of Colorado, I am happy to say my rear tires don't rub anywhere. I won't be needing an axle relocation plate.

 

I think your wheels and tires are contributing to this. ATX Artillery is -12 mm offset according to this page: http://wheelpros.com/brand-wheels/?wheelid=AX1886&siteid=2&groupid=5
Stock TRD OR wheel is +32 mm. That in conjunction with 285 tires means the outer shoulder of the tire has been pushed outboard by 52 mm or 2 inches over stock.

 

Yes, its a combination of things but with more up travel the wheels have more forward travel. If you get too much almost any 33" tire and rim combo will rub regardless of width. A reason you must run some sort of bumpstop. This post was started because there are members running my wheels and larger 295/70r17 tires, no cab mount chop and no relocate plates. This is very obviously not possible without eventual damage. I find most of the rubbing issues dont get enough direct factual attention ... just wanted to bring light to it so someone does not go buy Toyo or Nitto 295s and think they will fit and if 285s rub... how to solve it.