I am thinking about starting to put parts together for an axle swap, I come from a drag racing background where we use ford 9" axles a lot because they are light weight and can be made very strong. I know drag racing and a jeep are very different but couldn't a trussed 9" with a nodular iron center section be made plenty strong?

 

Hey Bad, I would think as long as you can fab,grind and weld you can make a 9" fit with few issues. I haven't done research on width but you obviously have donor choices (car, truck, etc.) to get it close, possibly without narrowing depending on wheels and your goal.

IMO, a N carrier would be way overkill as most of the stresses wheeling would be on housing flex and ring/pinion. As you know, that carrier is almost a necessity in drag cars that are suddenly shocked with a shit ton of torque (I have plenty of exp. in that like you). You didn't mention how aggressive you are but it's likely you wouldn't even need to truss. However, if you were fabbing one into a JK anyway, it would be an easy addition.
It's such a strong axle assembly and they're so readily available that I wouldn't have an issue throwing one in as is if I thought I needed it and had the ways, means and parts at my disposal.

Just my .02.

 

9 inch axles are extremely popular in the offroad world as well. Currie makes a 9 inch for the jk. Various tv shows and mags have covered it. I've seen guys running 40" tires on em

 

9s (and now 10s) are really popular in the offroad world as well. Look up Spidertrax...

 

Ruff Stuff makes a new housing (the housing is not really expensive, something like $800). Solid Industries makes hub kits that will work with that housing and that also work with the JK electronics (if you desire to keep them). I went through the whole process recently and was determined to go with 9" axles. Long story short, I am not going that route. It gets expensive fast. There are a few things I didn't end up liking.

- You need to run a low pinion rear and for a low pinion, the 9" is really low (drive shaft will be eating rocks for lunch).

- The center section is not as high clearance as it is made out to be. There are some CAD comparisons floating around that show that.

- Yes, they are popular in the race community. Part of it is that you can easily change gearing depending on the race (you just swap out third members). However, there is some question as to the durability for regular use (i.e. street driving).

- In terms of high pinion, you can drop the cash and get the Tru Hi9. That said, guys have had issues with leaks, etc. Again, probably fine if it is a buggy and you don't mind downtime and the extra work.

- Knowledge and parts just aren't as readily available as something more standard.

They are lighter, but you're sort of pissing into the wind if you have a JK. Maybe you save 150lbs.

That all said, they are pretty cool. I just wheeled with a guy in a JKU on 40s with 9" axles. As a coincidence, he works on an ultra4 team and has access to cheap parts and free labor.

 

My neighbor has two 9" diffs in a Jeepster. I'm pretty sure they are Currie built with Detroit Lockers. They were a freat swap several years ago and work well for him. But the Dana stuff is hard to beat for availability & parts, plus there's a size for every wallet!!

 

I built a spidertrax 9" and was a nice housing. Ruff stuff makes a nice housing as well. Local shop here did some of their 14 bolts on a full sized chevy and were bad ass. As far as third members you also have Hi9 and the mega hi9 for a super strong high pinion rear. The gears are crazy strong.

 

The only concern I had was after researching the Hi9, there were tons of comments regarding leaking seals, and other small problems, and having to send the 3rd members in for repair. Most of those comments were followed by something regarding bad (or maybe slow/less than ideal) customer service.

I have no first or second hand experience, but it gave me pause. The gears and axles are definitely strong though.

The downside to the mega 9 is it only comes in a 5.40 ratio.

Why did you swap out the 9"?

 

It was a front axle I built for my old tj. I considered building mega hi9's for my JK but ended up just buying dynatracs instead.

 

You could do it on a jk. No one here has but as total said most people that are out here are running all 10" stuff. Hp front lp rear. There damn strong axles. Im sure theres cheaper gears but i know lorens gearworks gears with his sponsorship is like 1500 per r&p set.

My old roomate has a 9" on his yj and its been thru a couple cv breaks on his driveline.