In the process of building some new axles and stuck between the pro rocks and the F9s.. IMO, the 9" design is superior with extra bearing but also a big fan of the pro rock housing and the bigger gear set.. Not sure if the extra bearing in the 9" makes the gear set stronger or not.. Love to hear some opinions from people that have experience with either/both and some technical comparisons..

 

Yes, a Ford 9" rear does have a third bearing on the pinion nose to eliminate pinion to ring deflection under high torque load. That may be the only area that a F9" could have a slight advantage over a ProRock. However, a ProRock will always beat an F9" in clearance MD the overall strength of axle tubes and axle housing. With the weight of a modern JK running huge tires, heavy beadlocks, armor, winches, bumpers and lots of gear for the trail, I decided reliability and strength were paramount to getting me to the trail, through the event, back home, and with daily driver duties around town. I have enclosed a photo of the ProRock series of axles, the cutaway shows the super thick axle tubes that F9"s don't have. From top to bottom 44, 80, 60.

Edit: I do have experience with Ford 9" rears, but it was on a drag car that I ran, so it doesn't really apply here.

 

So in your opinion, would a pr 44 be stronger than an F9 as well? Always had a soft spot for the 9"ers from hot rods as well.. Something to add is I don't do much rock crawling at all, mostly high speed back country trails on 40's..

 

couldn't have said it better myself.

i believe the 9 would have a stronger r&p being that it would be bigger than a 44 but, when it comes to the actual housing, yeah, i would think the pr44 unlimited would be strong and have WAY more clearance. GCM 2, please correct me if i'm wrong here.

 

The F9" would theoretically have a only a slightly stronger ring and pinion simply because it's larger; if that was the only thing being compared. But the entire axle as a whole needs to be looked at because the flexion of thin axle tubes and deflection of the ring and pinion due to poorly designed differential housings can completely null and void having just a giant strong r&p. The strength, by way of design, of the axle tubes thickness and gusseting on the differential housings on the Dynatrac product, cancel out almost any of the positives of the Ford 9" might have. On the matter of clearance, the PR44 and PR60 beat a Ford 9" by a lot! I have seen more breaks on turn key, bolt-on F9" style axles than I have Dynatracs. That's why I bought ProRock 60's, but you are going to pay more for that much quality when comparing to other manufacturers.

Also, let me add that we are not comparing the custom F9" "Race Builds" you might see out at king of the hammers under tube buggies. Those are pure custom housings, third members, outers flanges, etc. all made from super pricey, sometimes extemely lightweight, other worldy strong metals.

 

So it sounds like when you put all the factors together (materials, tube thickness, engineering design, etc.) the F9 is outgunned in all aspects as a PR44 as well? How would you compare the strength of a PR44 with your typical Dana 60?

 

Great info by the way!!

 

I'm going go out on a limb, but from talking with Scott (Dynatrac rep here on the forum) reading his post and just BS'ing with Dynatracs owner, I would say a PR44 is about as strong as a Dana 60. Now if you do the PR44 hybrid with 1 ton PR60 outers, like the Vengeance build here on the Forum, than I think you might have something equally as strong as a standard Dana 60. I am not certain and I hate putting out bad or inaccurate poop, so I hope someone corrects my info if I'm wrong.

 

A built Ford 9" with a true hi 9 3rd member is supposedly the best front axle for wheeling (from what i hear). It's what all the hi dollar buggies run on koh. Hope you have deep pockets though. Go to true hi 9's website to see the clearance on that thing.

Not speaking from experience, but it's probably worth looking into.

 

There has been some great info posted here and I really appreciate the comments.

In reference to clearance, I've posted a pic below. This very clearly shows the difference between our PR60 and a fabbed housing.

There is no question that a 9" gear is very strong, at the same time it also has some weaknesses that make it a less than perfect choice for off road use. In a front axle, to build it as strong as a 60 you'll need a True-Hi9. Aside from being very strong it's also very expensive. Also, like the PR60, it's really only needed once you get over a 37" tire. Forgetting about axle shafts for a moment- how many front Rubi 44 gear sets have we seen broken? Ever? Any size tire, any weight? The answer is close to zero. A PR 44 with good shafts is enough for 37's and down and a Hybrid 44/60 will survive much larger tires yet. A PR60 is pretty much good for anything but the competition rock bouncer and those guys break EVERYTHING.

In a rear axle one of the major differences is ground clearance. Even in LP to LP applications, the 60 has an edge. I know some will argue, but to me, just the drive shaft angle is huge difference. A 9" has the pinion center line at 2.25" below the axle center line. A Dana 60 pinion is 1.125" below the axle center line. An 1-1/8" may not sound like much but it makes a huge difference in a rock machine. Additionally, the 9" third member has a ring of bolts that act like a shovel and a pinion guard is a must-have item. Keep in mind that a large reason that the 9" is so popular with racers has been the ability to quickly change ratios for different tracks. This isn't a concern in our off road world. Going to a HP 9" rear, again, requires a True-Hi9 but results with this combination haven't been consistently good in a DD application.

To me personally, even taking off my Dynatrac hat, I find the ground clearance of the PR to be its biggest asset. I've been very lucky and have wheeled in many different areas with my Jeeps. I've seen the difference, first hand, that the clearance and housing design makes when wheeling in nearly any location.