• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

4" or 4.5" backspacing

HandBuiltXJ

HandBuiltXJ

NAXJA Forum User
Location
Oceanside, CA
Hello, long time reader, new to posting. My Truck..
93 xj 4wd, 4 door.
4.61 L stroker (40 over with 4.2L crank and 96 4.0 HO head)
2" shackle and coilspacer lift
I will be using this to run chase truck for My buddy, so i will be running fast and just wanted to have the best chance of not cutting my new tires or blowing a bead.
???????
I just got some Cooper STT 31x10.5 and am wondering
1. 15x7 or 15x8 for jeep speed style desert running at around 13-15 psi?
2. If I need 4" or 4.5" backspacing to keep em from rubbing.
I don't mind cutting my truck, i plan on doing the TJ flares any ways.
3. Would installing larger studs be benificial for our design or are our hubs the weak link?

Any input will be greatly appreciated.
Thank you
John
 
The less backspacing, the farther the tire will stick out. If I'm not mistaking most stock wheels have 5 inches of backspacing.
 
I vote for the least amount of backspacing to get the job done. The further you move your wheel out, the more torsional stress you put on the hub assembly and hub bearings. Which inturn increases bearing wear and can lead to hub failure.
 
i want to run the cragar soft 8's in the 15x7, but all i can find is 4" backspacing, that won't work with 31x10.5 will it? I would probably rub on the fender huh? i am half tempted to just through them on stock rims and change my LCA in the front to the bent ones, but for 150 bucks, it would be nicer to have new rims for my new tires..

john
 
Last edited:
They'll just stick out from the flare .5" more, but they'll fit fine. Bumpstop adjustment would be wise as to not tear off you flares due to them hitting the outside of the flare, etc.

Use the SEARCH button; seek and you'll find!
 
aplatz said:
They'll just stick out from the flare .5" more, but they'll fit fine. Bumpstop adjustment would be wise as to not tear off you flares due to them hitting the outside of the flare, etc.

Use the SEARCH button; seek and you'll find!
Click to expand...
seaked and searched and even used the google search with the link on the how to search page, just no direct answers.

So 4.5" backspacing at 15 psi wont rub anything on the steering or trailing arms?
 
Yep that should be perfect. Remember though 7" rims not 8". With 8s you would most likely rub your LCAs.
You may want to go ahead and pull out the plastic wheel wells. If not you will probably lose them on the trail any way. That way some one else doesn't have to pick up your trash. :)
 
frogmanjohn said:
are you running 31x10.5 tires? and are your Cragars the 15x8 or 15x7? and are you using extended bumpstops?

john
Click to expand...


31x10.5 on 15x8 cragars with 4.75 bs. haven't done the bumpstops yet, but haven't done much to really flex yet, as most of the trails here are still ice covered. I measured for bumpstops, and looks like 3-4" extended in the bumpstops to clear the 31's in the fender well. That with the tires WAY stuffed-a condition I don't think I'll see with my jeep. I have tons of clearance around the LCA's with this setup. I have aftermarket LCA's, but with the space I have, I would think it would clear stock LCA's too.
 
Speaking of tires, I just ordered my 34"x10.50" LTBs today. My son is taking my 33 s which I never cared for much. The tread width is an 1.25 larger on these and the lugs on LTBs are awesome off-road. Had a set of 31s a couple years ago. Good tire, just brutal on flares and fenders which I have trimmed the crap out of since.
LTBs are awesome. Just kind of a pain on the pavement. They go where ever the grooves take them. Just means you have to pay better attention.
You ever try and talk tires with your wives. Man what a joke. They just don't get it do they ?
 
boise49ers said:
Yep that should be perfect. Remember though 7" rims not 8". With 8s you would most likely rub your LCAs.
You may want to go ahead and pull out the plastic wheel wells. If not you will probably lose them on the trail any way. That way some one else doesn't have to pick up your trash. :)
Click to expand...
The wider the rim with the same BS the more it will pull the tyre away from the control arms. Most will need 4.5" BS with a 7" and only 4.75 or even slightly more with a 8". For every inch the rim is wider with the same BS and tyre on the rim, you gain around a 1/2" of extra clearance on the inside as the tyre is pulled across and stands up straighter. Always run the MOST BS you can to save you hubs without rubbing. The more BS number the less they stick out.
 
You must log in or register to reply here.

Similar threads

K
How does backspacing affect handling? 3.75 vs 4.5 backspacing for 31 x 10's?
Replies
11
Views
4K
XJEEPER
XJEEPER
ZomBrady
Things are looking up or how a couple of XJs gave me back my life
Replies
6
Views
163
ZomBrady
ZomBrady
M
Best 4.5" Lift Ride Quality
2
Replies
36
Views
7K
75SV1
7
X
being ready for the expected unexpected (hardware for broken/rusted susp components)
2
Replies
24
Views
7K
Xjin85
X
Anak
Fixing What the Professional Fixed
Replies
7
Views
708
Bent
Bent
Back
Top