Tires, lifts, spacers, and the combination

[88lance]

2002 Z71 4x4 Tahoe.
Wanting to run 33x12.50, with a level. I'm not trying to crank the keys way up, just enough to bring it level with the back.
I have stock wheels, so some spacers may be required.

This guy is running 12.50's on the same rims but has 2" spacers on the back.

Does anyone know if I can use something smaller such as a 1 or 1.5 spacer in the back, or is the full 2" really what it takes to clear?

The front tires on these sit in slightly more than the rear stock, So if I could do something like a 1.5 on the front and a 1 on the back it would kind of even it out.
Just wondered if anyone knew what the minimums are.

As far as height goes, I shouldn't have a problem. If he's clearing 35 with a level, I would think my 33s should be good. I noticed he has a lift in the rear, but he's also running tires 2 inches taller, So I'm thinking I should be able to get 33s with stock rear height.

Can anyone tell me what the minimum spacer sizes are for a 12.50 with a level? Any other things I may be missing?

 

[Alex_M]

Spacers with that size tire are going to actually cause interference issues with the front bumper and possibly the fender as well because they will increase the swing of the tire from the pivot point at the ball joints. Without spacers you may swing it with only minor rubbing.

Look at some 285/70r17s which are 33" but a bit narrower; closer to an 11.5 width. You can run them with no spacers or a 1.25" spacer in the front and no spacer in the rear with stock keys cranked up.

The truck you posted has aftermarket lift keys in the front which is helping him clear that wide of a tire and it looks like he has only rear spacers, no front spacers.

 

[Alex_M]

Ah, he has 1" front spacers. That tracks. My Tahoe on 35s is a similar setup to his but narrower tires and a little less lift in the front. Same height keys but not cranked up as high. For 35s (more specifically 285/75r18s) I have 1.25" front wheel spacers with 3" keys cranked about half way, and 1.5" rear spacers with 3" coil spacers and sagged out coil springs from lots of heavy towing duty the first year or two I had it.

 

[88lance]

Ah, he has 1" front spacers. That tracks. My Tahoe on 35s is a similar setup to his but narrower tires and a little less lift in the front. Same height keys but not cranked up as high. For 35s (more specifically 285/75r18s) I have 1.25" front wheel spacers with 3" keys cranked about half way, and 1.5" rear spacers with 3" coil spacers and sagged out coil springs from lots of heavy towing duty the first year or two I had it.

I forgot to mention, I ordered aftermarket keys as well. So I will be running a similar setup to what he has, except I will not be cranking them up as high since I'm not lifting the back as well.
I will just raise the front up to be level with the stock rear.
As far as clearing width goes, the guy in the video is running 12.50's and clearing, but I wonder if it's just because he cranked the keys up all the way...
The 2" less in height should help me since I'm going 33 instead of 35, but I'm not sure if the 12.50 has to have full crank on the keys to even work possibly?
It would be great if I could just raise it the 2" to level with the back and clear the 12.50's somehow.

 

[Alex_M]

I'd recommend cranking the stock keys first to see if you need more height. Usually that will set it pretty close to level with the rear and you'll save yourself the headache of swapping the keys. If you still want more height then you haven't costed yourself any more than a few minutes under your truck.

There are a lot of variables at play here. I'd question why you're stuck on a 12.50 width - you'll save on tires and see better performance for less work with a 285/70r17 while still getting the same height.

If you're dead set on a 12.50 wide tire, you may be forced to go taller. Whatever you do, please remember to re-aim your headlights so the cutoff is below the windshield of oncoming traffic, especially small cars.

 

[88lance]

I'd recommend cranking the stock keys first to see if you need more height. Usually that will set it pretty close to level with the rear and you'll save yourself the headache of swapping the keys. If you still want more height then you haven't costed yourself any more than a few minutes under your truck.

There are a lot of variables at play here. I'd question why you're stuck on a 12.50 width - you'll save on tires and see better performance for less work with a 285/70r17 while still getting the same height.

If you're dead set on a 12.50 wide tire, you may be forced to go taller. Whatever you do, please remember to re-aim your headlights so the cutoff is below the windshield of oncoming traffic, especially small cars.

The stock keys are maxed out, and the front is still 2" lower unfortunately. So the torsion bars may just be worn out. I ordered the aftermarket keys, so I guess I'll see how it rides with those, hopefully I don't end up having to replace the bars.

I just really like the 33x12.50 because it has a good wide stance. Once they started getting towards 35" on an 11 wide they start looking too thin for my liking.
If this starts looking too complicated, I may need to just get the 285/70's and call it good though.

 

[Alex_M]

Understood. Yes, sounds like your torsion bars have sagged some. Not an issue, the replacement keys will solve that in that case.

I have the opposite inclination - always been more a fan of a tall skinny tire. To each their own though. When you get them sorted out post back what you ended up getting to work.

 

[88lance]

This photo below is pretty much exactly what I'm shooting for. Those have got to be 12.50 wide for sure, and running stock wheels. It's a shame that I don't know whose it is to ask what they had to do as far as spacing and all that.

I had an idea, I may take one of my wheels and tire off, and put the spare on at the moment. Find an old used worn out 33/12.50 and mount it on my good wheel, and bring it back to the house.
Then I can put it on the front and see what it needs, and then put it on the back and see what it needs..
With the truck raised up by the control arm, the weight of the truck will still have the suspension compressed. So it should be the same as if the truck was sitting on the ground. I could do something like put a 1.5" wood block across the lugs and mount the tire on top of the board, and then turn the wheel from lock to lock and see if and where it touches, or where it may touch if the suspension compresses more. This may tell me what size adapters I would need on the front and back.
That way I don't have all the tires mounted and find out that I can't drive it until I order and wait on adapters to be delivered while the truck sits on blocks.
The photo below looks like He's not having to run very much spacing though.

 

[Alex_M]

Couple things. First, a worn out tire will be dimensionally smaller than a new tire so you will not get an accurate read. Second, your lug studs are not long enough to have a 1.5" block of wood between the hub and the wheel. Third, the suspension moves some back and forth under acceleration and braking because of the give in the bushings.

I think you're on the right track with the keys and 1.25" wheel spacers - it's just going to be a matter of how high you have to adjust it. Also remember, with wheel spacers that thin you will have to cut the unthreaded first half an inch off each lug stud with an angle grinder.

Even your alignment will effect clearancing, though I've generally gained a little clearance when getting an alignment so you should be all right there.

 

[88lance]

Couple things. First, a worn out tire will be dimensionally smaller than a new tire so you will not get an accurate read. Second, your lug studs are not long enough to have a 1.5" block of wood between the hub and the wheel. Third, the suspension moves some back and forth under acceleration and braking because of the give in the bushings.

I think you're on the right track with the keys and 1.25" wheel spacers - it's just going to be a matter of how high you have to adjust it. Also remember, with wheel spacers that thin you will have to cut the unthreaded first half an inch off each lug stud with an angle grinder.

Even your alignment will effect clearancing, though I've generally gained a little clearance when getting an alignment so you should be all right there.

Good points. I may just have to get as close as I can guesstimate with the old tire by messing with it some, order an adapter, and actually mount and try it. If it works, order the rest. If it doesn't, hopefully I would be able to tell what I needed to correct it from that.
On the black Tahoe it looks like the rear doesn't have any spacing, and the front seems to be spaced a little bit.
So I'm not sure why the guy in the video spaced the rear two whole inches, unless he just wanted that look, or had something to do with the two extra inches in tire height somehow. Hopefully I don't have to run adapters that thick.

I noticed you have some pretty big tires on yours, maybe a little bit thinner though like you mentioned. What did you have to do with yours?

 

[Alex_M]

Yes, I'm on 35x11.50s (285/75r18). I have 3" keys cranked about half way - I think actually 2" over maximum stock keys. I believe the rear is also about 2" over stock using spring spacers.

I've got 1.25" wheel spacers front and rear. Was necessary in the rear to clear the 35s.

I previously ran several sets of 33x11.50s (285/75r16) with just cranked front keys. I ran those both without any wheel spacers, and with 1.25" front wheel spacers. Worked well both ways. IMO honestly the perfect setup for a rig that will see limited or no off road use. The 35s are good, but I have considered going back to the 33s and lowering the height back some when I wear this set of tires out. In reality, limited off road use is all the GMT800s are good for unless you do a solid axle swap anyway, which I would like to one day but it is far from immediately pressing.

 

[88lance]

Yes, I'm on 35x11.50s (285/75r18). I have 3" keys cranked about half way - I think actually 2" over maximum stock keys. I believe the rear is also about 2" over stock using spring spacers.

I've got 1.25" wheel spacers front and rear. Was necessary in the rear to clear the 35s.

I previously ran several sets of 33x11.50s (285/75r16) with just cranked front keys. I ran those both without any wheel spacers, and with 1.25" front wheel spacers. Worked well both ways. IMO honestly the perfect setup for a rig that will see limited or no off road use. The 35s are good, but I have considered going back to the 33s and lowering the height back some when I wear this set of tires out. In reality, limited off road use is all the GMT800s are good for unless you do a solid axle swap anyway, which I would like to one day but it is far from immediately pressing.

Where does the rubbing happen on the rear? Is it mostly because of height, or because of width? I'll be going down an inch, but out width-ways an inch compared to yours, so it may give some idea of what I'll run into.
I was confused because I keep seeing people say "the tire was really wide, so I had to go up an inch". I wasn't sure how "up" is helping anything on the back side. Is it hitting where the fender well starts curving out or something?

If it's hitting right on the back side of the tire with a 1.25 spacer, the 12.50's are going to be harder to make happen.
I found a worn out nitto 35/12.50 and got it today, it's probably worn down to 33". Nitto mud tires run the full 12.50 measurement, so it will be a good gauge to see what I'll need to adjust.

The leveling keys don't get here until Wednesday unfortunately. I'm looking forward to messing with it to see what I can/can't make happen.

 

[Trey Hardy]

Where does the rubbing happen on the rear? Is it mostly because of height, or because of width? I'll be going down an inch, but out width-ways an inch compared to yours, so it may give some idea of what I'll run into.
I was confused because I keep seeing people say "the tire was really wide, so I had to go up an inch". I wasn't sure how "up" is helping anything on the back side. Is it hitting where the fender well starts curving out or something?

If it's hitting right on the back side of the tire with a 1.25 spacer, the 12.50's are going to be harder to make happen.
I found a worn out nitto 35/12.50 and got it today, it's probably worn down to 33". Nitto mud tires run the full 12.50 measurement, so it will be a good gauge to see what I'll need to adjust.

The leveling keys don't get here until Wednesday unfortunately. I'm looking forward to messing with it to see what I can/can't make happen.

You ought to clear 35/12.50s in the rear stock you may need some wheel spacers if you rub on the inside with the stock wheel. But that ain’t an issue.
With keys and minor trimming you ought to get atleast 3/4 turn or more out of em.
My buddy had a 04 with 3” keys we had 20x12s and 33/12.50s on it for a long time and for a min there we threw the 20” snowflakes and 35” terra grapplers on it and I don’t remember clearance ever being much of a issue
We did the normal nor cal mod to the front valance/plastic and trimmed the inner fender/cab corner nothing that was noticeable from looking at it unless you got up under it…

 

[88lance]

You ought to clear 35/12.50s in the rear stock you may need some wheel spacers if you rub on the inside with the stock wheel. But that ain’t an issue.
With keys and minor trimming you ought to get atleast 3/4 turn or more out of em.
My buddy had a 04 with 3” keys we had 20x12s and 33/12.50s on it for a long time and for a min there we threw the 20” snowflakes and 35” terra grapplers on it and I don’t remember clearance ever being much of a issue
We did the normal nor cal mod to the front valance/plastic and trimmed the inner fender/cab corner nothing that was noticeable from looking at it unless you got up under it…

That's great to hear, maybe this won't need as much of adjustment as I was thinking. The new ones I'm getting will be 33's, so that will help some also, dropping two inches down from the 35.
I'm really hoping the rear won't need big spacers, the back tires already track wider than the front stock. I'd hate to push them out another 2".
I heard The front will start rubbing worse if you space it out very much. So I guess one of my big concerns is if the back needs spaced way out, and the front has to stay stock, it would look kind of goofy.
If the back needs an inch or something, and the front could handle 1.5", that would look pretty good though, they would be pretty well in line.

 

[Trey Hardy]

That's great to hear, maybe this won't need as much of adjustment as I was thinking. The new ones I'm getting will be 33's, so that will help some also, dropping two inches down from the 35.
I'm really hoping the rear won't need big spacers, the back tires already track wider than the front stock. I'd hate to push them out another 2".
I heard The front will start rubbing worse if you space it out very much. So I guess one of my big concerns is if the back needs spaced way out, and the front has to stay stock, it would look kind of goofy.
If the back needs an inch or something, and the front could handle 1.5", that would look pretty good though, they would be pretty well in line.

I think the back only rubbed on the fender liner with the 35s and stock rims. With the offset wheels it weren’t a issue

As far as wheel spacers go a lot of crowd has ran 2” with the stock 17s and 35s with a leveling kit and they could still turn 3/4 of the way or more without scrubbing
It’s usually the wider aftermarket wider wheels with wheel spacers and not enough lift is when you have issues.
I think the biggest we ever cleared without a full blown lift was my buddy’s 05 we did 3” Keys 1.5” body lift and stuffed 22x14s on 33/12.50s and she cleared just about full lock.
A couple years later he got a 07 and he couldn’t fit them with just a leveling kit so he stepped down to 20x12s and 33s and they still scrubbed a lil bit.

 

[88lance]

I think the back only rubbed on the fender liner with the 35s and stock rims. With the offset wheels it weren’t a issue

As far as wheel spacers go a lot of crowd has ran 2” with the stock 17s and 35s with a leveling kit and they could still turn 3/4 of the way or more without scrubbing
It’s usually the wider aftermarket wider wheels with wheel spacers and not enough lift is when you have issues.
I think the biggest we ever cleared without a full blown lift was my buddy’s 05 we did 3” Keys 1.5” body lift and stuffed 22x14s on 33/12.50s and she cleared just about full lock.
A couple years later he got a 07 and he couldn’t fit them with just a leveling kit so he stepped down to 20x12s and 33s and they still scrubbed a lil bit.

Ah, if the front can handle a 2-in spacer, then I guess that would just keep the stock tracking if the rear needed a 2-in also. That wouldn't be bad.
Of course I'll try to keep them in as much as I can, I prefer not to run very big spacers, but whatever the spacing needs to be, as long as they can be pretty similar from front to back would be good.

It's unfortunate that my torsion bars have sagged so much, I'm curious how much lift I can actually get out of my 3-in keys. The stocks are turned all the way up and it's still 2" low in the front. As long as it will bring it up level with the back though, I should be good with clearing the tires.

 

[Trey Hardy]

Ah, if the front can handle a 2-in spacer, then I guess that would just keep the stock tracking if the rear needed a 2-in also. That wouldn't be bad.
Of course I'll try to keep them in as much as I can, I prefer not to run very big spacers, but whatever the spacing needs to be, as long as they can be pretty similar from front to back would be good.

It's unfortunate that my torsion bars have sagged so much, I'm curious how much lift I can actually get out of my 3-in keys. The stocks are turned all the way up and it's still 2" low in the front. As long as it will bring it up level with the back though, I should be good with clearing the tires.

Unless you get a knuckle style lift kit that pushes your track width out the front should be even with the rear If im not mistaken

Anything under 1.5-2” spacers you’ll have to trim your wheel studs to fit the spacer. That’s why I lean towards the 2” so no trimming
I’ve had spacers for 10 years no issues you just make sure they are torqued good when you install em.

 

[88lance]

Unless you get a knuckle style lift kit that pushes your track width out the front should be even with the rear If im not mistaken

Anything under 1.5-2” spacers you’ll have to trim your wheel studs to fit the spacer. That’s why I lean towards the 2” so no trimming
I’ve had spacers for 10 years no issues you just make sure they are torqued good when you install em.

Oddly my front seems to be in about 1/2 to 3/4" compared to the back. Not sure why. It's not very noticeable, but if you really look you can see it. I assumed that's the way they all were. Maybe it has something to do with my front suspension.

I don't mind trimming wheel studs, but it would definitely be easier to just use a 2-in spacer rather than trim. It may require that anyway to fit the tire with. Do you know if 1.5" requires cutting them, or does it just depend on the brand of spacer?

 

[Trey Hardy]

Oddly my front seems to be in about 1/2 to 3/4" compared to the back. Not sure why. It's not very noticeable, but if you really look you can see it. I assumed that's the way they all were. Maybe it has something to do with my front suspension.

I don't mind trimming wheel studs, but it would definitely be easier to just use a 2-in spacer rather than trim. It may require that anyway to fit the tire with. Do you know if 1.5" requires cutting them, or does it just depend on the brand of spacer?

1.5” requires trimming 2” don’t require trimming
1/4” or 1/2” will work without trimming
I think your right the front is in more on the 99-06 vs the rearend
Most lift kits widen the track width up front depending on the brand

Most 3” keys will only give you 1.5-2” of lift
Back in the my highschool days we would rob 2000 model ford f150 keys from the junkyard and install them uncranked would give us around 2” and cranked up would net around 3” or more

 

[88lance]

1.5” requires trimming 2” don’t require trimming
1/4” or 1/2” will work without trimming
I think your right the front is in more on the 99-06 vs the rearend
Most lift kits widen the track width up front depending on the brand

Most 3” keys will only give you 1.5-2” of lift
Back in the my highschool days we would rob 2000 model ford f150 keys from the junkyard and install them uncranked would give us around 2” and cranked up would net around 3” or more

Wow, my 3" keys may not be enough then, considering my stocks are maxed out and I'm 2" low still. So the Ford keys give more height then the 3" lift keys, I didn't know that. I may need to send them back and go the Ford route.