How much is too much backspacing? What's ideal?

Blackhawkip

Blackhawkip

Member
I know several of the wheels out there run a 3.5" backspace and that seems to be ideal for running 37 or 40" tires. I've searched the threads and can't find the answer to folks are running less than 3.5". My wheels are 4.4" backspace and am running 1 1/4" wheel spacers with 37x13.50R17 SST Pros. I am running a coil/king 2.5 res 4.5" lift and have a PR44 with ProSteers and Reid knuckles.

With my setup, that puts my backspacing around 3.15". Any issues or concerns? Other than maybe having to rebuild my ProSteers maybe a little quicker, anything else?
 
DWiggles

DWiggles

Caught the Bug
Blackhawkip said:
I know several of the wheels out there run a 3.5" backspace and that seems to be ideal for running 37 or 40" tires. I've searched the threads and can't find the answer to folks are running less than 3.5". My wheels are 4.4" backspace and am running 1 1/4" wheel spacers with 37x13.50R17 SST Pros. I am running a coil/king 2.5 res 4.5" lift and have a PR44 with ProSteers and Reid knuckles.

With my setup, that puts my backspacing around 3.15". Any issues or concerns? Other than maybe having to rebuild my ProSteers maybe a little quicker, anything else?
Click to expand...
addressing your thread title:
the IDEAL back spacing for each set up is going to be the least amount (largest BS#) you can fit without any rubbing.

addressing your specific question:
no. 3.15 isn't "too much" but it is a LOT. the ProSteers are pretty overbuilt. I would think the unit bearings will see significantly accelerated wear, as well as the increased likeliness of bending a rear flange. the unit bearings are the only real issue if your not wheeling the jeep. If you ARE wheeling the jeep, I'm sure you will be sick and tired of changing the rear shafts due to bent flanges in pleanty of time. And you will change the setup to something a bit... "less aggressive"
 
Blackhawkip

Blackhawkip

Member
DWiggles said:
addressing your thread title:
the IDEAL back spacing for each set up is going to be the least amount (largest BS#) you can fit without any rubbing.

addressing your specific question:
no. 3.15 isn't "too much" but it is a LOT. the ProSteers are pretty overbuilt. I would think the unit bearings will see significantly accelerated wear, as well as the increased likeliness of bending a rear flange. the unit bearings are the only real issue if your not wheeling the jeep. If you ARE wheeling the jeep, I'm sure you will be sick and tired of changing the rear shafts due to bent flanges in pleanty of time. And you will change the setup to something a bit... "less aggressive"
Click to expand...

Thanks for the reply. I swapped out my axle shafts to a RCV front and TenFactory rear. I wish I could afford the PR60 full-float rear but that will be a looonnggg while down the road.:) I'm taking my JK back into EVO tomorrow for the 500 miles service on my gears. I added the spacers based on the wheels I was running when I had the lift installed. Two weeks later, I found a deal on a set of the MOPAR beadlocks I couldn't pass up. Hate to spend another $200 on another set of spacers but may do it so save on wear/tear on everything.
 
wayoflife

wayoflife

Administrator
Staff member
Blackhawkip said:
I know several of the wheels out there run a 3.5" backspace and that seems to be ideal for running 37 or 40" tires. I've searched the threads and can't find the answer to folks are running less than 3.5". My wheels are 4.4" backspace and am running 1 1/4" wheel spacers with 37x13.50R17 SST Pros. I am running a coil/king 2.5 res 4.5" lift and have a PR44 with ProSteers and Reid knuckles.

With my setup, that puts my backspacing around 3.15". Any issues or concerns? Other than maybe having to rebuild my ProSteers maybe a little quicker, anything else?
Click to expand...

So that we're all on the same page, what you're really asking is how much is "too little" back spacing. Factory is 6.25" and anything more than that would be too much. Technically, anything less would be too. With that said, 3.5" is far from "ideal" but it will help you to clear big tires at a full turn and flex. In my opinion, 3.5" or less like you have is too little as the center line of your wheel will be way off center and this will increase your scrub radius, leave your lower ball joints exposed and will put a lot more stress on your ball joints and unit bearings. While your ProSteers will hold out longer than most ball joints, your unit bearings will fry a lot faster. As DWiggles pointed out, it'll be a lot easier to bend rear flanges too.
 
Blackhawkip

Blackhawkip

Member
wayoflife said:
So that we're all on the same page, what you're really asking is how much is "too little" back spacing. Factory is 6.25" and anything more than that would be too much. Technically, anything less would be too. With that said, 3.5" is far from "ideal" but it will help you to clear big tires at a full turn and flex. In my opinion, 3.5" or less like you have is too little as the center line of your wheel will be way off center and this will increase your scrub radius, leave your lower ball joints exposed and will put a lot more stress on your ball joints and unit bearings. While your ProSteers will hold out longer than most ball joints, your unit bearings will fry a lot faster. As DWiggles pointed out, it'll be a lot easier to bend rear flanges too.
Click to expand...

Thanks Eddie, I've read your comments on spacers in other posts. With 4.4" backspacing on the wheels, what size wheel spacers would you recommend? Could I get away with a 1/2" spacer to take my overall to 3.9" backspace total?
 
wayoflife

wayoflife

Administrator
Staff member
Blackhawkip said:
Thanks Eddie, I've read your comments on spacers in other posts. With 4.4" backspacing on the wheels, what size wheel spacers would you recommend? Could I get away with a 1/2" spacer to take my overall to 3.9" backspace total?
Click to expand...

I would NOT recommend running anything less than 1" wheel spacers as there would not be enough material to do it safely. 1.5" is idea on a JK as that's what's needed to clear the factory wheel studs. You can cut them down to run a thinner spacers but again, I would not recommend it. The best option would be to run wider axles and with wheels that have more back spacing but obviously, that's not something most people can afford to do.

Being that you're running 13.50 wide tires, you're options are really limited. Running wheel spacers like you're doing now is probably the only thing you can do to make it work without rubbing at a full turn and stuff.
 
notnalc68

notnalc68

That dude from Mississippi
wayoflife said:
So that we're all on the same page, what you're really asking is how much is "too little" back spacing. Factory is 6.25" and anything more than that would be too much. Technically, anything less would be too. With that said, 3.5" is far from "ideal" but it will help you to clear big tires at a full turn and flex. In my opinion, 3.5" or less like you have is too little as the center line of your wheel will be way off center and this will increase your scrub radius, leave your lower ball joints exposed and will put a lot more stress on your ball joints and unit bearings. While your ProSteers will hold out longer than most ball joints, your unit bearings will fry a lot faster. As DWiggles pointed out, it'll be a lot easier to bend rear flanges too.
Click to expand...

So, about like Chamber Pro's, at 4 inches for 37's?
 
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