15" Rims: steel vs. aluminum

The '89 MJ Eliminator that I am restoring for fast street use (see 2wd vs. 4wd thread) has the aluminum rims that came as part of the Eliminator package on it. I plan on making this thing clean & sharp looking (as opposed to my trail XJ, which is dirty, ugly and wrinkled)with nice chrome bumpers and accent pieces as found on Laredo's & Limiteds from the same era.

I have a set of fairly new chrome AR Tailgunner rims under my deck that I could put on it instead of cleaning up the aluminum rims. They would certainly match and look good, but would there be any noticeable performance loss in going with a heavier steel rim?

I don't think youed knowtice much the factory alum wheels are actually kinda heavy . If you were to test them on the jeep with very good testing equipment they might show a diffrence.

No, there is a marginal weight difference between the aluminum rims and the Tailgunners. One thing to consider though is the width of the rims. I would go with the wider rim seeing as though you'll be putting some sort of lower profile tire on it (right??). I have a set of the 16" wheels from a 2000 Cherokee. The only reason I did this was because I had two 245-50-16 and one 225-55-16 tires laying around already.

A 255-50-15 tire will easily go on an 8" rim, and fit into the rear wheel openings. I think it would fit in the front wheel openings too.

A.

I bought the Tailgunners with a set of 31x10.5 Bridgestone AT's on them... I think the rims are 15x7 w/ stock backspacing, so as far as I know the only upgrade would be cosmetic. I plan on getting this thing into racing trim very slowly, so I may just use up the 235/75 tires I have laying around first.

Recently someone on JU weighed the factory steelies against the alum grizzlies/ecco's and the difference was 8.5lbs per wheel. So there is definitely a difference and since you want a street machine one of the key issues is weight reduction. 32+ lbs is a big difference in that aspect.

Ya that is a bit of a diffrence bu it seems like the newer wheels are lighter than the older alum ones I'll have to dig out my gold lace wheels do some comparisons

Those gold lace rims are kinda heavy as I recall...but strong. You know 17" rims are cheap to have nowadays and they are all around the best size for just about 99% of applications, this conclusion from numerous magazine tests I read in acceleration and handling. Bigger than 17" and the weight penalty is too great, smaller and your handling/looks suffer. Also 17 fits very nicely in that huge wheel well.

XJguy

One of the main considerations in racing applications is 'unsprung' weight; that is, the amount of weight at each corner that goes directly to the ground (tire, wheel, hub, axle/diff, conventional outboard brake, etc.). The less unsprung weight, the better; that's the main reason many performance cars go to inboard brakes.

On a *typical* racing setup, the front suspension is independent. A weight difference of 8.5 per corner is a HUGE difference in unsprung weight. It really affects the response of the springs and shocks to road input.

On a solid-axle rear, that already has 250 lbs of unsprung axle/diff, 17 lbs at two corners will have no measurable effect.
On a straight axle MJ 2wd front axle, there might be some difference in handling but 17 lbs of additional unsprung weight would be negligible compared to the awful road handling that is inherent in a straight axle (compared to independent).

Of course, for absolute acceleration/cornering/braking, 34 lbs. less vehicle weight is a worthy achievement.