I have the GF p/n 91200 shims too and NO issues in 10K miles.
BTW- if it were me, next go round I will get gf p/n 91201 due to getting o/e ford bushing and not poly bushings...fwiw.

 

shims are necessary any time you change the pinion angle. Just because you dont have vibrations doesnt mean you have the angle out of spec.

install is very easy, they just slide in between leafs and the top of the axle, after removing the U-bolts.

 

i dont see how shims would fix every pinion angle change resulting from lowering the rear.

 

are the rubber bushings that much better than the nylon bushings?

 

They are wedge shaped shims that, installed correctly, return the pionion to the proper angle in relation to the drive shaft. They work great if you are just using shackles to lower the rear.

 

they make different angles from anything from 1/2* to 6* or more (in half degree increments)

I dont see what is so confusing about how they help.

stock vs 6*


stock installed (drivers side)


6* shim installed (passenger side)

 

Im just scared I guess, I just got the truck and I love the ride and the no issues it currently has.. Im scared to do it and get some sorta vibration or problem, though obviously the shims can be installed to correct this, Im just scared I may try and install the shims and screw something up, Ive done shackles before on my S10, And I dont see how a small 2 inches would affect it, though some shackle kits come with shims and some dont, but how come in suspension lifts and lowering kits nothing is ever said about pinion angle needing to be corrected by some sorta shim and the effects of those kits are larger with anywhere of 4-6 inches of lift or drop from stock?

**Would the process be install the drop shackles first, then just keep the truck up with frame on jackstands and support the rear axle with floor jack then simply unbolt the ubolts drop the axle down just a hair to allow removal of the stock shim, then install the new shim, jack it back up to seat the shim to the bottom of the leafs and bolt the stock ubolts back in-- Im assumin this would be the correct way one could go about doing it? Are you suppose to torque the ubolts down to a spec? All I got is hand tools.

 

That is all you have to do. Hand tools are adequate. It did not change my truck at all as far as vibration and ride. made it corner better and I love the near level stance. I got the GF kit specifically because I wanted the shims. Did not want to change the pinion angle at all.

 

^--Thats clean.. thats a sharp truck, all you have done to it drop wise is the rear drop shackles in the rear?? It looks damn good like that, has a good sit to it and them rims and tires work perfect on it,, nice job.. How much do some of those Roush 22s run.. man Id love to have a set on my all white f150 regcab, thanks for the enlightment and the pic. Looks like Im going to more than likely go for it now, where did you get your kit from Jim? Is the OEM bushings really a more desirable kit to get, the 91201 kit is like $110 w/o shippin, I can pick up the 91200 for like $95..

 

I believe jim has 20s not 22s

 

Thanks for the compliments. I just could not stand all the open wheel well on the rear, so lowering it 2 inches really improved that. I have the 91200 kit, bought from a local truck shop.

I bought the Roush wheels off craigslist. Got lucky, paid $675 with a nearly new set of tires on them. In fact, the tires in the pics. You can get a set pretty reasonable in our classifieds, occasionally. Those wheels are ridiculously high if purchased new but you can find them used. As Patrick said, they are 20s. They are my favorite wheel for these trucks. There are more pics that show the stance in the albums on my profile.

 

Anyone happen to know what company produces and makes the Summit Brand drop shackles, They have the GF 91200 kit in stock along with a same exact lookin kit even includes the shims its listed as Summit brand 2 inch drop shackle kit? I was curious thinkin possibly GF could be producing this kit for Summit, its looks identical.. b/c I have yet to see any other shackles kits out there that include shims with the shackles as a kit, DJM doesnt Belltech doesnt.. the GF 91200 kit is like $110 and the Summit kit is $95.. I was thinkin of gettin the summit ones, I may call GF or Summit and try to get the answer on this.. please feel free to check them out and let me know what you think..

 

I need shims. Anyone have any to sell? Or a shim only supplier?

 

shims can be bought on stylintrucks.com

do you already know what degree shim you need?

 

I need to figure that out. I droped 5 inch in the back.