Racing Application: Light weight or stronger built?

REDLYNER

REDLYNER

Mall Crawling Race Rig
Joined
Oct 31, 2008
Location
Mountain Island
I'm debating about which way would be the most short term beneficial, meaning if one of these choices had to last me a year or so, which would net me the opportunity to be faster offroad (2 options)-

Option 1, bigger rear axle:

I currently run heavy 37" tires on built Rubicon 44 axles. But because they are Rubi 44's, I can't run it very hard. Meaning in a race, I can't hammer it up hills like I would like and I can't bounce around over rocks or logs like I would need to to carry competitive speed (because of fear of breakage). I already busted a ring and pinion on the course- So the obvious solution it seems would be to install bigger axles.

But... there are tons of variables here. Cost wise limits me to just a rear axle- which puts width and bolt pattern into play.
  • Do I get a new custom built 9" (65" wide) axle, then have to run adapters for my 5x4.5 pattern? Puttin me at 68" My front would still be at 65" (stock width plus 2" spacers)
  • Do I get a used full width and run two different lug patterned wheels?
  • Will I be any better off running a rear custom 9" or 60, but still have the weaker front Rubi?
  • Should I hold out for a rock jock with a rear 5x4.5 bolt pattern? But then what do I do a year from now when I replace the front axle?

Other option, get lighter:

The jeep weighs around 4100lbs right now, here are some changes I could do before the next competition:

  • Change from 37" Pitbull tires to 37" MTR/Ks and save 16lbs per corner. That's roughly 60lbs of rotational weight.
  • Swap front tube fenders for aluminum highline fenders and save roughly 70lbs, maybe more.
  • Swap rear comp cut corners for aluminum comp corners and save another 35lbs.
  • Swap steel belly up for aluminum under armor system and save roughly 40lbs.
  • Remove front windshield for race and save another 70lbs.
  • Remove the rear tailgate and save around 25lbs.
That would drop around 300lbs or so and I'm sure I could find some other stuff to remove. However, I will be adding more cage work, fuel work, and a few other things, so I'm not sure where the total saving will end up. Is 300lbs worth it? What if 60 of those pounds were rotational? Am I just putting lipstick on a pig, or would that much weight removal play a major part in my axles holding up under more abuse?



Any feedback is welcome. I like the idea of the lighter weight stuff because of all of the new aesthetic changes it would give my jeep (it's not all about just function for me), but my brain says the axle is the smarter play. However, it seems to come with more issues since I can't do front and rear at the same time.
 
I think the correct answer is "yes".

Here's the other thing: you don't talk specifically about what kind of racing you want to do. Nail down what that is, then build accordingly. I will say this much: I'm no racer... so the guys that are can feel free to disagree with me on this. But if you're serious about going to KOH, I wouldn't want anything with a 5 on 4.5" bolt pattern under the vehicle. I'd want more shock than you've got now, less tire, and a lot of seat time getting the suspension dialed in. I'd also get rid of every unnecessary pound on the vehicle. Whether or not that weight comes back in tube or tools doesn't matter, since you would have added the tube and tools anyway.
 
You will notice the weight savings from the tires more than all of the other weight savings combined.

If you are getting a custom 9", getting it narrowed should be no problem at all, as well as getting the 5x4.5 bolt pattern. That will be the next major mod to my jeep.

I have a set of 5x4.5" to 8x6.5" adapters that are 1.5" thick that I ran on my front D30 when I had a rear D60. They worked out great, I put probably 40k miles on them. I'll sell them to you if you go the 8 lug rear route.

At the end of the day, a trussed 9" with 35 spline shafts is going to be the best balance of strength and weight. For how much the rear of a jeep weighs, you really don't even need the truss, but if it will make you feel better, do it.
 
I'd start with a junk yard 9inch rear, and swap in new 35 spline shafts. Have the shafts drilled for both the 5 on 4.5" lug pattern, and maybe 5 or 6 on 5.5 if that is what you think you might go to when your get around to swapping the front end.
 
I'd build a rear 60, run adapters on front, lose any weight that is bolted on, and change to Goodyears. Or you could build a 9 for more money to save 50 lbs or so. I would not use semi float axle shafts. it's fun spending other people's money for once. You can give me a call if it'd be easier.
 
I'm with Travis, I wouldn't run a semi float axle. Custom 9s are cool but you need a fair share of shock work and the extra coin spent on the 9 vs the 60 probably isn't worth it right now.
If you could swap both axles at once that would obviously be the easier way to go but that's a lot of coin at once unless you find a killer deal on built axles.
 
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