Changing Rims...backspacing issues? spacers required?

[BlackAura]

Hey guys, I'm currently running stock Rubicon Moabs (16x8, 5" backspacing, 12mm offset), and I'm looking at buying the tire/rim combo XJHERO has up for sale.  The tire size will be essentially the same, so no issues there, but as far as I can tell the rims are the Ecco rims (see the 5th rim down in that post).

These rims are 15x7, 5.5" backspacing, and 38mm offset.

According to this calculator I should be fine, but of course, there's the extra half inch of backspacing, and the extra half inch of tire diameter.  I've heard the Rubicons are close to rubbing as it is, so I'm wondering if anyone has had any experience with this swap before.

Also...will the fenders look stupid?  I understand the rims won't sit out as far.....should I just get spacers?
...on that note, where can I buy spacers and what cost am I looking at?

Thanks!

Edit: Short and sweet so Tubby might actually take the time to read it  

[w squared]

Spacers are probably going to reduce your effective backspacing by 1 to 1.5 inches. Make VERY sure that you buy the good ones that have a new set of studs offset from the holes for the existing studs. The cheap type that are just a plate with holes in it are bad juju. Very bad juju!

To make sure that I'm clear, you want your spacers to look like this:



Northridge carries those - they are 1.25 inch spacers. $125 a pair. I'm sure that other places in town could supply them for you.

By the way...understand that reducing your backspacing like this will shorten the life of your unit bearings. But then again....if we gave half a fart about the lifespan of parts, we wouldn't be lifting our Jeeps and putting bigger tires on them.

[WhiteOut]

x2 on the Spidertrax, but running then won't hurt bearings more than a rim than is backspaced to a similar measurement. I have had mine on 3 Jeeps now with zero issues.

[JackstandJohnny]

don't bother buying a new set of stock sized tires kevin, or you'll be selling them in a few months time too because you'll wanna go bigger. 

as for spacers, modern has em on the shelf for like, 125$ or something a set,

or Paul (parabs) has a set of spidertracks for 200$, which is worth it.

until you get 'inchitis' and put a 3" on it, and 33s.................

[w squared]

running then won't hurt bearings more than a rim than is backspaced to a similar measurement. I have had mine on 3 Jeeps now with zero issues.

Agreed - I didn't communicate as well as I could have there. Whatever you do that reduces backspacing (either different wheels or adding spacers) will increase the stress on your bearings. This is not something to lose sleep over - I think that we just want you to be aware of all the various factors at play here.

[BlackAura]

don't bother buying a new set of stock sized tires kevin, or you'll be selling them in a few months time too because you'll wanna go bigger. 

Haha, well, I won't be looking at bigger tires until at least next spring for sure, and I don't really mind driving it on 31s, but I guess there's the odd run I can't do that requires 33s.  I think I'd prefer to look into a tummy tuck first, like Slewfoot is doing, before I look at lifts / tires.

or Paul (parabs) has a set of spidertracks for 200$, which is worth it.

Awesome, if I go for it I'll pick these up from Paul.

Agreed - I didn't communicate as well as I could have there. Whatever you do that reduces backspacing (either different wheels or adding spacers) will increase the stress on your bearings. This is not something to lose sleep over - I think that we just want you to be aware of all the various factors at play here.

Good to know, thanks Todd!  I've read something about getting good ones with proper studs before, nice to get that confirmed.

Regarding lifts and bigger tires vs wear and tear on parts, that's one of the reasons I haven't gone lift / tire crazy yet.  I'm daily driving this thing over the winter and I've read about people who go far enough to turn their Jeep into a trail only rig, and have to get a winter beater.....my Jeep is my "winter beater"

[WagoneerXJ]

those Ecco rims should have 5.25" of backspace, not 5.5"

[Spinalguy]

My source disagrees ^

Ecco
* 15x7 aluminum
* 5 on 4.5" bolt pattern
* Backspacing = 5.5"
* Offset = +38 mm