what backspacing does the 1979 fj40 have? 3.5" ? If I were to use 2" bs, that would push each wheel out 1.5" right? What would be any disadvantages of doing this? Also how is back spacing measured. Thanks

I believe that 3.5 is right. With identical rims and tires you would have a 3" wider stance with the 2" backspaced rims (1.5" on each side) However I would not suggest that you do this with a normal rim. Only a beadlocked rim.
By spacing the tire out you get a wider track and a bit more stability. However you also get a LOT more stress on the bearings. So proper upkeep will be necessary. Also if you are running larger tires, 36" or so. The greater offset will keep your tires from rubbing the springs in the front during turns and off of the inner wheelwell in the rear.
Backspacing is measured from the back side of the wheel mounting flange to the inner edge of the rim....

I am running beadlocks with a 2" backspacing

My friend is (and I will be soon) running 36x12.5 TSLs on a 15x8 rim with 2" BS. No loss of bead problems yet. It does probably put more wear on the bearings, definitely more stress, but it seems to be OK. He hasn't even broken a birf yet and runs the old coarse-spliners. The 2" BS is perfect. Excellent tire fit and wider stance, but not ridiculous. I wouldn't do 2" BS on a 10" rim though, maybe 3"BS for a 10" rim.

BS is measured as the distance from the mounting surface to the inside of the rim.

[ 10-01-2001: Message edited by: FeCamel ]

Originally posted by FeCamel:
<STRONG>I wouldn't do 2" BS on a 10" rim though, maybe 3"BS for a 10" rim.

BS is measured as the distance from the mounting surface to the inside of the rim.

[ 10-01-2001: Message edited by: FeCamel ]</STRONG>


What would you do on a 12" rim????
Why wouldn't you run a 10" wide rim with 2" backspacing??????

i jsut got some 36x12.5 swampers w/ 15x8 rockcrawlers, w/ 3 5/8" bs, or 3.5, i think its 3 5/8..they dont rub on my springs on full turn or anywhere when turning, when i flex it out, it will be a whole different story..they look fine even though they dont stick out in the fornt much, but they do a little in the back

With a 10" rim and 2"BS, you have 8" of rim beyond the mounting surface. With 12" rims and 2"BS, that's 10" sticking out there. That is a lot of torque on the bearings and birfield. If you're running tires big enough to need a 12" rim, you probably have upgraded axles so it won't be as big of an issue. The narrower rim also helps keep the bead. I like to keep the rim about 4" narrower than the tire. This also allows for the tire to bulge a little and keep the rim off the rocks. the downside is tire crowning, but if you inflate to the proper (lower) pressure, you can still get a very nice contact patch.

These are just my personal opinions and what I would/wouldn't do on my own rigs. It is by no means gospel. I'm sure some people have 12" rims with 1" BS and are fine, that's just a little more stress than I want my poor little axles to have to deal with.

[ 10-01-2001: Message edited by: FeCamel ]

Fecamel, 15x8 with 2" BS sounds good to me, where did you get your rims and was the 2"BS like some kind of special order?
I prefer the cheap-ass steel white spokes, the cheaper the better. I destroyed my rims the last two seasons. I'm always bending them on the rocks, then I'm beating them back into shape with a hammer, that's why I like em cheap, they're disposable. <IMG SRC="smilies/biggrin.gif" border="0">

hey Don, Im runnin 15x8 w/2" bs on my rig. They are steel white spokes. They where a "custom bs"
I think it was $200 out the door at Americas tire.
<IMG SRC="smilies/beer.gif" border="0">

We got our 15x8 2"BS special order from Bart Wheel. We ordered 10. They are kinda pricey, but worth it. We paid $71 each including shipping to our door, a good price, but not really a "disposable" price. We got them in about a week. I really like them, they fit perfect. The steel is pretty tough, and it can be pounded straight if you hurt them too badly like you said. Stockton Wheel wanted $91 each plus shipping! Shop around and see what kind of deals you can get.

Originally posted by FeCamel:
<STRONG>My friend is (and I will be soon) running 36x12.5 TSLs on a 15x8 rim with 2" BS. No loss of bead problems yet. It does probably put more wear on the bearings, definitely more stress, but it seems to be OK. He hasn't even broken a birf yet and runs the old coarse-spliners. The 2" BS is perfect. Excellent tire fit and wider stance, but not ridiculous. I wouldn't do 2" BS on a 10" rim though, maybe 3"BS for a 10" rim.

BS is measured as the distance from the mounting surface to the inside of the rim.

[ 10-01-2001: Message edited by: FeCamel ]</STRONG>

Yeah, no mechanical breakage yet, but my body is starting to look like sh*t! <IMG SRC="smilies/wink.gif" border="0">

Isn't that what the body's there for? You're just jealous because my body has more dents and scratches. I must admit you've been adding the "body modifications" at a good rate lately.

Hey FeCamel,

Could you tell me exactly where you got your rims with 2" BS? A website or address or phone number? Thanks.

Busdriver,
Trailready made my spare 15x10 w/2" backspacing for $45. Give them a call and see what they can do for you.


Trailready (http://www.trailready.com/)

p.s. Their beadlocks rock!!!!