go fast straight axle

[toocoolforschoolTJ]

What are some of the keys to a good go fast straight front axle that you more experienced desert guys can enlighten me about. also some good pointers on SWB rigs would be nice too

[TRD]

Check out Goat1's Jeep...

[Lance]

Just the opposite of rock crawling - trussed and light weight. Our Jeepspeeds have Dana 30's in em.

[Beat95YJ]

Search for Goat1, and Dusty Booger. Components can be lighter but will need trussing as Lance suggested.

[toocoolforschoolTJ]

I remember when I first saw that thing I was blown away(Goat 1's Jeep). So yeah I'll do some searching. Okay so truss the hell out of it and keep it light. I'm thinking of a set of 9"s front and rear. I already have the rear in and the stuff to make the front. Also I was thinking of going with a radius arm type three link front, does that system get a little squirly when you go from full droop to full stuff? thanks guys

[TRD]

If you want a lot of travel I wouldnt go radius arm.

I would also shoot for more anti-dive in the front than rockcrawling.

[skullver]

here is our trussed Dana30 for our jeepspeed rig:

[strokeddodge]

Im workin on a go fast long travel strait axle, Im sure everyone has seen the threads, The nick name is "Tippy"

[tsm1mt]

Originally Posted by Lance

Just the opposite of rock crawling - trussed and light weight. Our Jeepspeeds have Dana 30's in em.

And in case it's not obvious to everyone - an UNDER-axle truss is stronger for the weight than an over-axle truss. On the trail, you want an over-truss to avoid bashing it on the rocks, but you pay for it in extra weight.

I have a simple under-axle truss on my front D44. Just some 1" cold-rolled but it's kept the front end from smiling for a number of years now (first, untrussed front end DID make a smile for the crowd after 3 years).

If you thought you tore out balljoints fast on your big-tired rock-crawler, you'll rethink that after you pound 'em out while racing.

[JESSE_at_TLT]

If I was building the ULTIMATE go-fast front axle, it would be a fabricated 9" housing (maybe something like Huseman's new Pro-4 housing) with a Hi-9, Longfield CV's and maybe a set of those lightweight Spidertrax knuckles.

[raceanything]

No desert experience here but quite a bit of air time under my staight axles.It's amazing how light a truss can be and hold an axle together.
As tsm1mt said tension is much better for strength but kills ground clearance.
If you want the best of both worlds try a cable truss. That's right...Take a 3/8" cable loop around each knuckle "C" and under the diff. Tie it together with a good turnbuckle and tighten it after jumping a few times. You'll be amazed at how well it works, just watch that you don't dig in and slip it out of position.
It only weighs a few pounds and you can take it off for rockcrawling.

[Bubba Ray Boudreaux]

Dredged up from RDC

More RDC straight axle talk

[GoodTimes]

Originally Posted by JESSE_at_TLT

If I was building the ULTIMATE go-fast front axle, it would be a fabricated 9" housing (maybe something like Huseman's new Pro-4 housing) with a Hi-9, Longfield CV's and maybe a set of those lightweight Spidertrax knuckles.

I don't think those knuckles would hold up.

[toocoolforschoolTJ]

a dana 30 just isn't going to cut it for the HP i'm planing on running, I'm not really thinking jeepspeed at all. I will be using a Jeep, but it is a TJ, and I'm planning on doing a lot of things for it that wouldn't be race legal. Mainly it will be a trail rig that I can do mild rock crawling with, and be able to go at least 50mph pretty much anywhere, and jump whenever I want. I'm not planing on running anything larger than 35" tires, and will probably end up stretching the WB, as to how yet I am not sure. But I do need to figure out something as far as the front suspension. I am planning on running a late 70's caddy big block with as much alum. shit as I can get on it, which I am told makes it in the ball park of the weight of a chebby SB. but there is going to be at least a 2.5 co all round and probably a set of bypasses in the rear. I don't really care how much of a bitch anything is or how to fit it cause I can fab just fine, and don't really plan on making any comprimises. Performance is number one. In fact I'd consider IFS if i knew more about fabricating a decent 4wd system, but I just don't have that kind of evperience. cheers all.

[Dusty Booger]

You could build a Dana 44 with HD shafts and joints or maybe a Ford 9/Dana 60 hybrid that could be built lighter a stock 60 front.

[toocoolforschoolTJ]

i'm either going 9" front or 44 front no 60's no 30's I am just curious about suspension tech. Apprently no radius arms and keep it light is the key. And I'm talking linked susp here as well.

[JESSE_at_TLT]

The additional kingpin/balljoint separation on a D60 is going to add a LOT of strength compared to a D30/44. If you're building a big-block and plan on driving it hard, I wouldn't recommend using anything less than D60 knuckles with whatever center-section you want to run.

[tsm1mt]

Originally Posted by JESSE_at_TLT

The additional kingpin/balljoint separation on a D60 is going to add a LOT of strength compared to a D30/44. If you're building a big-block and plan on driving it hard, I wouldn't recommend using anything less than D60 knuckles with whatever center-section you want to run.

Big tires + big-air results in premature balljoint failure even more frequently than big tires, lockers, and rocks.

For a big heavy truck and lots of abuse, the king-pin 60, as heavy as it is, sure sounds good.

Isn't the late model style 4x4 Chevy (TT if I'm not mistaken) running a solid 60 front?

[toocoolforschoolTJ]

good info, but a jeep TJ is hardly big, nor heavy. I think I'm going to go the 44 route and carry some spares. if shit blows apart then I'll make something work. I don't think power had much to do with ball joint failure so much as tire size and weight. also backspacing probably has a part to play I'd imagine. Like I say, the info I'm really looking for is on suspension. But since no one seems to be saying anything I'll probably just try and fit a triangulated four link in there somewhere. and put some big stiff shocks on it.

[Bubba Ray Boudreaux]

Originally Posted by toocoolforschoolTJ

and put some big stiff shocks on it.

Try spending some $$$$ on shocks. You can't go fast unless the suspension is working and putting some crap $50 shocks is just gonna break stuff cause they'll fade within a couple of minutes....................

[tsm1mt]

Originally Posted by toocoolforschoolTJ

good info, but a jeep TJ is hardly big, nor heavy. I think I'm going to go the 44 route and carry some spares. if shit blows apart then I'll make something work. I don't think power had much to do with ball joint failure so much as tire size and weight. also backspacing probably has a part to play I'd imagine. Like I say, the info I'm really looking for is on suspension. But since no one seems to be saying anything I'll probably just try and fit a triangulated four link in there somewhere. and put some big stiff shocks on it.

4-link or radius arm would be fine, though a trailing setup (4-link mounted to the frame end) would be best for the suspension, but suck for the driveshaft. I think Big Oly ran something like this. Typical RA setup makes the axle move forward and up on bump, and you rally want it to go up and back, but to pull that off, your radius arm / 4-link mounts would be very low, putting the RA parallel with the ground at ride height (more or less).

Run good shocks, tuneable. If you have the coin, run bypasses - you can firm up the valving as it gets closer to full bump while maintaining a decent ride quality mid-stroke. Use air-bumps to aggressively add spring rate at the end of the travel.

Power won't kill the ball joints, but if you're on the gas and land, it'll kill axle shafts pretty easily.

The landings are what waste my balljoints.

[raceanything]

I ran 44s front and rear for 6 years of Pro Arena (glorified tough truck) racing. ~40 events per year, 15 -20 jumps per event, some 12-14 feet under the truck at times. Jeep was 3025 lbs. leaf sprung, 14" travel, 2 white shocks per corner. We often landed on the gas with the wheels turned to start the next turn. Even landed on the crush cars a few times.
In that amount of timeo I recall: 1 ball joint, 3-4 front axles, 1 rear axle, two cracked rims and one housing breaking. Not bad. I ran 30" tires.

[AlumCJ]

back up...what about shocks? whats the go fast setup that can be put in a regular old 3200 lb 2 seat crawler? packaging bypasses could be tough with the tall tires and rear steer...think coil overs and airbumps is best? seems to me it would have to be better than the airshocks.

with the airshocks, i can't "plane" out on rough terrain...hurts too bad gettin there ...maybe some tuning would be best...or will my improvements only be marginal...

walker 2" x 14's by the way.

[mustange70]

Quick question as this has me confused, how is the under axle tuss stronger than the over axle truss? As steel is way strogner in compression then tension (i know as i've done tension tests and compression test in class), if someone wouln't mind explaining that would be great.

[tsm1mt]

Originally Posted by mustange70

Quick question as this has me confused, how is the under axle tuss stronger than the over axle truss? As steel is way strogner in compression then tension (i know as i've done tension tests and compression test in class), if someone wouln't mind explaining that would be great.

In compression, you have the tendency to want to buckle and fail.

In tension, no buckling possible.

It's not like we're talking about a rigid column in a skyscraper.


It's hard for the truss to fail under-axle, but easy over-axle, so you have to add more strength to compensate for the buckling tendency, thereby adding weight.

Pound for pound, the under axle is stronger.