Need Some Advice On Lifts

kckrawford · May 11, 2010

I've been reading through the forums and I've got a few questions that I haven't been able to seem to find the answer to.

I have a 2008 GMC Sierra SLE Crew Cab 4x4 w/ the Z71 Package.

I'm wanting to run 325/60-20 Nitto Terra Gapplers. I know that I'm going to need 6" of lift to accomplish this, but this is where the questions come into play.

I'm undecided on which lift I should run. I've been looking at the Fabtech and from reading on here, it seems as though you get 7-7.5" of actual lift out of their 6" lift. Just wanted to see if this is correct. Also, I'm looking for a lift that's going to be dependable. I drive quite a bit with an average of 25-30k miles a year, so I'm looking for a lift that will fair well with the amount of miles I'm going to put on it. I would like to be able to clear the tires with minimum cutting. I don't mind trimming a little bit, but would like to keep this to an absolute minimum. Would running a leveling kit on top of the 6" lift help with limiting my cutting?

Also, I'm wanting to run the KMC XD Series 775 Rockstar wheels. 20", but I'm not sure on the width and backspacing. Honestly, I don't quite understand exactly how the backspacing works, so what I'm looking for here, is someone to tell me what width to get (the 8.5" or 10") and what backspacing that I should run. I don't really want the tires sticking out a whole lot. I understand that they are going to be 2" wider than stock and that's fine, but I'd like to keep them as tucked as possible. Also, will the backspacing affect weither or not my tires would rub less/more and by getting the correct backspacing it would allow me to run the tires with minimum cutting?

DwelveAT · May 11, 2010

Fabtech is a good lift, I have it on mine. BDS is also a good lift too based off the reviews and compliments other have said on this forum. Based off the annual mileage you are putting on your truck, I dont know if getting a lift is the route you are wanting to go seeing gas mileage will drop, but if gas isnt an issue for you than by all means do what you have to do. Once others chime in, you are going to get a lot of advice from owners running either Fab, Bds, Pro, Sky, RCX, etc... I am not an expert on lift kits as I did the samething you are asking when it came time to mine. As for your baskspacing, 5" is a minimum require for these new body style for clearing issues. The higher your offset the more tucked in your tires will be, the lower the more they stick out. Mine are are a dead even 5" and they stick out roughly 1.5"-2.0" and again its going to be based off the knuckles your kit comes with. Fab comes with huge knuckles and widens the track of the vehicle.

Matt_ · May 11, 2010

1) DONT run a leveling kit on top of a suspension lift, especially with the miles you put on your truck. if you need another inch or so to clear the tires, Zone Offroad makes a 1.5" body lift for our trucks that'll do exactly that.

2) The amount the tires stick out is based off with and backspace. for example a 10" wide wheel with 5" backspace will stick out 2" FURTHER than an 8" wheel with 5" backspace. with that said.... for the KMCs id recommend getting the 8.5" wide wheels that have a backspace between 5.0 and 5.7.

3) as previously mentioned there are a lot of quality lifts out there. if I was ordering today, the 6" BDS would be high on my list.

jimmyboy8301 · May 11, 2010

the 325/60/20 tire is closer to a 35.6x13x20 so on an 8.5" wide wheel thats pushing the limits. i would run a 35x12.5x20 and get the 8.5" wide wheels. the backspacing should be around 5" - 5.7" . the fabtech is a good kit, but the options it comes with suck especially for the price, however the kit is closer to a 7-7.5" kit. a lot of people have a lot of problems with fabtech's TRE's.

i think the 2 best 6" kits on the market are the 6" Superlift and the 6" BDS hands down. they are both reasonably priced, both have the option of full leaf springs, both you can get with full coilbodys (no spacers) and the superlift (and i believe bds also) give you the option of bilstein 5100 shocks.

stlavsa · May 11, 2010

the 325/60/20 tire is closer to a 35.6x13x20 so on an 8.5" wide wheel thats pushing the limits. i would run a 35x12.5x20 and get the 8.5" wide wheels. the backspacing should be around 5" - 5.7" . the fabtech is a good kit, but the options it comes with suck especially for the price, however the kit is closer to a 7-7.5" kit. a lot of people have a lot of problems with fabtech's TRE's.

i think the 2 best 6" kits on the market are the 6" Superlift and the 6" BDS hands down. they are both reasonably priced, both have the option of full leaf springs, both you can get with full coilbodys (no spacers) and the superlift (and i believe bds also) give you the option of bilstein 5100 shocks.

had to replace the tie rod end BOOTS on the fabtech one time, second time around no problems. got almost 8" of lift from it not 7 inches. Got like 7 3/4 to be exact. I had it on 33" tires and it was taller than a silverado with the 6" pro-comp with 35" tires. (both trucks having fairly new tires). You CAN get away with running a little extra spacer (maybe 1" but still prefer 1.5" body lift) on the fabtech kit it gives you a full diff drop. Kits like BDS dont drop the differential the whole way, and you shouldnt do it with them.

jimmyboy8301 · May 11, 2010

i've seen trucks get 6" of lift from the fabtech, i've seen trucks get 7", and i've seen trucks get 8". it all depends on the truck some sit high and some sit low. with my 6" Superlift on 35's i've sat just as high as some fabtech trucks with 35's. measure your lower crossmember from fabtech, then measure your diff drop and see if they are the same.

and with fabtech's kit you still get the stock crappy shocks, crappy shock tower, and rear blocks for the price of the superlift or bds with, leaf springs, new coilbody, and upgraded shocks.

DwelveAT · May 11, 2010

i've seen trucks get 6" of lift from the fabtech, i've seen trucks get 7", and i've seen trucks get 8". it all depends on the truck some sit high and some sit low. with my 6" Superlift on 35's i've sat just as high as some fabtech trucks with 35's. measure your lower crossmember from fabtech, then measure your diff drop and see if they are the same.

and with fabtech's kit you still get the stock crappy shocks, crappy shock tower, and rear blocks for the price of the superlift or bds with, leaf springs, new coilbody, and upgraded shocks.

Got a question, how are you guys getting these measurements? Do you measure from the ground to the first suspension component?

What sites are you guys finding BDS kits for sale with all the goodies for the equivlant price of a Fabtech kit, im just curious?

stlavsa · May 11, 2010

i've seen trucks get 6" of lift from the fabtech, i've seen trucks get 7", and i've seen trucks get 8". it all depends on the truck some sit high and some sit low. with my 6" Superlift on 35's i've sat just as high as some fabtech trucks with 35's. measure your lower crossmember from fabtech, then measure your diff drop and see if they are the same.

and with fabtech's kit you still get the stock crappy shocks, crappy shock tower, and rear blocks for the price of the superlift or bds with, leaf springs, new coilbody, and upgraded shocks.

Mine were the same just shy of 8 inches. Jimmyboy has good points where the other lifts do somethings better than fabtech (but height isnt one of em ). It is nice to have a whole new leaf pack instead of an add-a-leaf and a rear block, BUT i dont think you can get the Superlift with rear leafs for $1600.00 (fabtech price).

Also the strut extensions are a matter of debate. I agree with Jimmyboy that I dont think its the best way to do it, and certainly dont prefer them, BUT i havent heard of a single case where they havent performed perfectly. I have the same ride as I did when the truck was stock. Also its easy to get rid of the extensions, I am just going to run the longer bilsteins designed for 6-8" lift when the stockers are worn out. They are all good kits just different approaches, BDS gets to call their lift "high clearance" when in reality it just means they didnt drop the diff as much as they lifted the truck. Shouldnt be a problem though, unless you plan to add an extra spacer.

Also: I like you put on a bunch of miles every year, i use the truck for work. I also am running rockstars with the fabech. You would want to get the 10" wide wheels. The 8.5" wide wheels will require use of a wheel adapter to clear the spindle with that wide of a tire. The wider tires will also help the tires sit flatter on the road (flatter contact patch) and they will wear better. You shouldnt need to do any trimming with fabtech to clear those tires, you will probably need to trim a tad with the other lifts, I havent heard of anyone needing to trim 35s with fabtech, but have heard plenty of instances where trimming is needed with bds. (others should chime in here on that subject)

Matt_ · May 11, 2010

steve, its the backspace that matters for clearing the spindle,....not the width. a 20x8.5 with 5" backspace will clear the same spindle that a 20x10 with 5" backspace clears... and that 20x10 will stick out 1.5" further than the x8.5 in that case.

im not sure what the available backspaces are for the Rockstars... but i have a feeling that the 20x10 might be 4.5" backspace which would make that tire stick out way farther than the fender line... and although a 10" wide wheel is better for a 325 wide tire, the OP doesnt want them to stick out really far... so like James said he might want to look at a 315 or 12.5" wide tire to get better tread wear on the 8.5" wide wheels.

stlavsa · May 11, 2010

steve, its the backspace that matters for clearing the spindle,....not the width. a 20x8.5 with 5" backspace will clear the same spindle that a 20x10 with 5" backspace clears... and that 20x10 will stick out 1.5" further than the x8.5 in that case.

im not sure what the available backspaces are for the Rockstars... but i have a feeling that the 20x10 might be 4.5" backspace which would make that tire stick out way farther than the fender line... and although a 10" wide wheel is better for a 325 wide tire, the OP doesnt want them to stick out really far... so like James said he might want to look at a 315 or 12.5" wide tire to get better tread wear on the 8.5" wide wheels.

yep I know its the backspace I guess the way i posted it was kinda ambiguous. I said it that way since we are discussing ONLY rockstars. When your talking about rockstars, if you go with the 10" wide wheels it will give you the backspace you need to clear the spindle. Theres only one backspace available for 10" (atleast last time i checked). There are a couple available for the 8.5" but neither are really what he needs.

stlavsa · May 11, 2010

steve, its the backspace that matters for clearing the spindle,....not the width. a 20x8.5 with 5" backspace will clear the same spindle that a 20x10 with 5" backspace clears... and that 20x10 will stick out 1.5" further than the x8.5 in that case.

im not sure what the available backspaces are for the Rockstars... but i have a feeling that the 20x10 might be 4.5" backspace which would make that tire stick out way farther than the fender line... and although a 10" wide wheel is better for a 325 wide tire, the OP doesnt want them to stick out really far... so like James said he might want to look at a 315 or 12.5" wide tire to get better tread wear on the 8.5" wide wheels.

oh didnt notice the part about not sticking out. Regardless if you want the wheels to fit your need to run that backspace. I have the fabtech, i have rockstars in 20s (8.5") and they rubbed the spindle with 305/55/20s. Needed about an extra 3/4 of an inch to give a comfortable amount of clearance. I went with 1.5" wheel adapters

edit:

Looking at KMC site and this one should clear it:

http://4wheelonline.com/KMC_XD775_Rockstar...ck.67486.458668

Its an 8.5x20 and its 5.14 backspace 10 offset. I believe MY wheels were the 6.14 backspace with 35offset. (i had chose those wheelse initially becaus i was running just a leveling kit) Like everyone said though, if you want to run the 8.5" wheel you definatey want a 305 or 315 tire. IMO the best would be go 325 and 10" wheel and some pocket style fender flares. It will look awesome. Lifting your truck 7-8 inches and keeping your wheels at a stock backspace will make it look top heavy.

Matt_ · May 11, 2010

what backspace does your wheels have?

stlavsa · May 11, 2010

what backspace does your wheels have?

i edited my last post as you replied i put the backspace in there. Now that i think about it, with backspace i linked it should be pretty close to the backspace of my wheels combined with the 1.5" spacer. They still stick out just a 1/4 inch or so beyond the rivet/pocket style fender flares I am running. I def wouldnt want 325s on these wheels. I am going to a 35x12.5 and I wish I had the 10" wide wheels

Matt_ · May 11, 2010

lol thats exactly what i was thinking... the 20x8.5s come in both 5.14 and 6.13 backspace... so if you had the 6" backspace wheel then the OP would probably be set with the 5" backspace

6" backspace will have clearance issues with most kits on the market whereas the 5" seems pretty standard and works well with the gmt900 lifts.