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backspacing and rim size?

282K views 175 replies 120 participants last post by  20Jeep15! 
#1 ·
dumb ? but what is back spacing and If I plan to get new rims for my 06' TJ

what is the bolt pattern and would 16" rims give me any benefit over 15" rims
thanks ton.
 
#153 ·
I have a 13' Sahara 2 door with 2.5" Rubicon express lift. Currently have 17x9 Pro Comp wheels and 35x12.50x17 Pro Comp AT tires. I want to get the Metal Moto 18x10 -27mm offset wheels with 35x12.50x17 tires...Anyone know if the change in wheel width and -27mm offset will cause a problem? Thanks
 
#155 ·
Read the thread, still not fully getting it..

I'm looking at 2 options, trying to understand the difference between the two if someone has a minute :)

1) 4.75 bs -6 offset
2) 4.5 bs -12 offset..

Thank you in advance
 
#156 ·
Read the thread, still not fully getting it.. I'm looking at 2 options, trying to understand the difference between the two if someone has a minute :) 1) 4.75 bs -6 offset 2) 4.5 bs -12 offset.. Thank you in advance
Back spacing is the final distance from the inner lip of the wheel. So in your first example, the hub sits 4.75" in from the back side of the rim. Offset tells you how far from the center line of the rim the hub sits. So, take a 9" wide rim. Adding 1 " for the lip of the rim gives you 10". The center line of this rim is 5" from the back side of the rim. Offset simply tells you how far the hub is from this center line. A negative number means the hub is closer to the back of the wheel, giving you less overall back spacing. A positive offset then means the hub is farther from the back. So, if this is a 9" rim in both your examples above, the centerline of the wheel is 5" from the back. -6 offset is roughly .25", giving you 4.75" back spacing measured from the back of the wheel. -12 is roughly .5", giving you the 4.5" back spacing measured from the back of the rim. Got it?
 
#159 ·
OK Brain Trust this is what I got in mind and wonder if with this set up tire rub won't be a problem.

2015 JKU with stock 16" steel rims. Current.

Looking to keep stock 16" steel rims and add a 33.4" tall 295/75R 16 tire and add 1.25" spacers.

Is this sufficient to not rub, or would it not rub with out the spacers?

Thanks in advance!
 
#162 ·
Ok still a little confused after reading this but,
If I got a 2001 wrangler 4.0 with a 3.25 lift and wanted to use the Pro Comp Series 51 Rock Crawler Xtreme 1-Piece 15 X 8 wheel with 3.75 backspacing and a 31-1050RLT inch tire I should be fine right ?
Wheels confuse me thanks for any help
 
#163 ·
Too many numbers...

Hi. Complete newbie here.

I'm in the process of ordering a 2016 Sahara JKU. This will be primarily a DD but I do want to do "light" offroading. I intend to have a Teraflex 2.5" lift kit installed. I really like the look of the FUEL Octane D509 and the Rugged Ridge XHD wheels and would like to pair with Goodyear DuraTrac 35 inch tires, preferably the 315/70R17. Here's the kicker: I would very much prefer to have the tires stay within the lines of the stock fenders but not also cause a rubbing problem.

Can this work? How do I go about picking the correct backspace/offset/etc. to do what I want to do?

Thanks in advance!
 
#164 ·
Trying to make sure my math is right.

My baby is an '06 Rubicon TJL, all the mods are in the Sig :happyyes:.

Currently running 265/75R16's which convert out to roughly 32x10.5, on the stock 16x8 7mm offset (aka 4.25" backspace)

Thanks to whoever posted Custom rims, wheel tire packages for your ride - RIMSnTIRES.com as it has been more helpful than I can describe. :Thanx:

I'm looking to keep, really increase the tire height and with, but also minimize the rubbing while turning I get with my current setup. I don't like how narrow my Rubi sits on the 265/75's currently, looks too tall and out of proportion to me. She's been on 13,000' mountain passes, and 18" of Everglades mud so function is higher on the priority list. :happyyes:

Here are the numbers I've figured out:

  • Stock: 245/75R16 or 30.5 tall x 9.65" wide
  • Current: 265/75R16 or 31.7 tall x 10.4" wide. That .4 inch is enough to get me rubbing against the arms. 4.5" front fender clearance, 8" in the rear with the new Bushwacker's all around.
  • What I want: 305/70R16's or 32.8" x 12", the magic 33x12. This setup is 1.2" closer to the arms than the stock setup.
Debating 15x10 or 16x10 rims which I think would require a 4" BS for the 10" rims to get the inside of the tire back where I want it, not rubbing. If I stay with my current 16x8's I think I need 1.2 spacers, or a 3" BS if I go with new 16x8 rims.


I don't think I'll have fender rubbing issues, at 33", but thoughts there are welcome also.

Does that sound about right?

Thanks in advance.


 
#165 ·
Thanks in advance for anyone who can give me help. I've read loads of the topics on here but have to admit I got a little lost with everything.

I've been looking for a set of 18's to replace my stock wheels (also 18's) I was told it was best to stick to same size with it causing less issues.

I want a wide stance on the jeep for the aggressive look etc.

I was looking around for best deals and saw a set of black rhino sierras on eBay. It had the best offer function so I stuck in $900 and the guy accepted - seems like a good deal to me?

Here is the thing...

1.) What tires should I get (99% road use)
2.) what does offset ET-12 mean? (That's in the description)
3.) do I need spacers or other mods?

Thanks and pics below of wheels

Matt (jeep newb)
 

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#167 ·
I'm looking at a wheel that is 9inches wide, and has 2 backspace options... a 5 (1mm), or a 5.75 (20mm).

I will be running 35's, and want to keep them as tight under the fenders as possible, but without rub. I want to run an AEV 2.5 dualsport lift, and will trim the rubicon rock rails. I want them tucked in as much as possible.

Is running the 5.75(20mm) going to make it way too hard to avoid rubbing? Is the safe bet the 5.0 (1mm)?
 
#168 ·
Ok so I'm trying to get this right. I need -13mm offset which is 4" of back spacing to put on a 12.50 wide tire. I'm trying for 33's on some new wheels. I was gonna just us the canyons and run 10.50. But my buddy's tell me to get 12.50. Thanks in advance. I don't wanna mess the order up.
 
#171 ·
Ok, so I've read this thread and I must be tired or something because it's just not totally sinking in. I'm such a tire noob!

I found and am picking up tomorrow some used KO2s 285/70r17s, which I figured comes to about 32 inches, I think. Maybe 33. I found that they'll be a smidge wider than 11". Will the stock Rubicon or Sahara wheels be ok with this? Will it give my Jeep a more aggressive stance and look?

Also, I don't have to lift or anything special for this size of tire, right? Teacher on a strict budget here!
 
#173 ·
Ok, so I've read this thread and I must be tired or something because it's just not totally sinking in. I'm such a tire noob!

I found and am picking up tomorrow some used KO2s 285/70r17s, which I figured comes to about 32 inches, I think. Maybe 33. I found that they'll be a smidge wider than 11". Will the stock Rubicon or Sahara wheels be ok with this? Will it give my Jeep a more aggressive stance and look?

Also, I don't have to lift or anything special for this size of tire, right? Teacher on a strict budget here!

245s are 30.5", 265s are 31.6", 285s are 32.8".
 
#174 ·
Clueless: What offset for new wheels and tires

NEED ADVICE: Putting a leveling kit on the jeep and then new wheels and tires. The old tires 255/75/17 on a 17x 7.5 wheel (Door sticker). The new tires will be 285/70/17 ......"Fuel Assault" wheels 17x9. My question is what offset should I get if I want the wheels to be a little wider than now (stock) but not sticking way out past the fender? The wheels come in a -12mm offset with 4.5 backspace OR +1mm offset with 5 backspace. PLEASE HELP!
 
#176 ·
So much great information. I've got a stock JK, stock wheels which are in perfect shape and like the stock look. But time for new tires, so here I am. Stock tires are 255/75R17, basically 32" Looking hard at jumping up to 285/75, 34" Possibly, 255/80, 33". These tires should last for years and years so want to make sure right. It's riding around on weekends, road use, no off-roading, not a daily driver. I'm worried about room with stock wheels and slightly wider tire.

Extreme Terrain tire and wheel expert telling me 285/70 is most popular size for upgrading on stock JK wheels, not issues at all with rubbing. 285/75 same width or slightly smaller depending on tire so wouldn't have any issues.
Wondering if I need to buy a set of wheel spacers just to be sure!?
 
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