9" vs. 9.75" rear axle??

[desertspeed]

I have a 2001 F150 Supercrew with the 9.75" rear axle, and this happened last week. Obviously time for an upgrade..... So, my question is, wouldn't the 9.75" rear axle found in the newer f150s be stronger than the 9" that it replaced? It seems like every built rear end is based on either a 9' or the 10.5" on full race rear ends.

I have searched everywhere I could think of to get a good explanation on why the 9" is a better platform than the 9.75", but haven't found anything. Is is simply a matter of better availability, or is the 9" really stronger for some reason?

Thanks!

[1971Ford]

i dont know but you really should reinforce the rearend more. as in weld some tubes to it for reinforcement.

[desertspeed]

Yeah, that's the plan......

[goofballracer]

i think there are companys that do a truss kit for the rear end. all ive ever seen are the 9" in sure the 9.75 would works i think you could use the same dimension one you have there and truss it or have someone truss it it will make a world of a difference

[goofballracer]

http://www.race-dezert.com/cgi-bin/trader/atl.cgi?ct=7&md=second&id=4187
something like this

[Alex Paterson]

The 9.75 has a bigger ring and pinion but is weaker with a cast center section and weaker axle tubes. I think if you pulled just your run of the mill 9" out of a Ford Van you may not realize a great increase in strength but when you compare it to a 9" fully fabricated rear from a good company like H&M, Dirt Tech, Tubeworks, or Currie you will get a much stronger set up.

I have seen the 9.75 trussed and work well and Solo Motorsports even had new axel tubes pressed into one on a Supercrew to widen it.

It you switch over to a 9" based axle you will have to move your VSS tone ring to the slip yoke on the trans. LeDuc offers a kit as does Brea Auto Electric. I would expect to pay anywhere from $150-$250 for the VSS parts. I bent my factory 9.75 on the drivers side as well but not nearly has bad as you have. I ended up going with a fully built H&M rear end with 5.0 gears and a Detroit locker and Pro Am hubs w/ Wilwood discs. I ran the Brea Automotive VSS relocated to the slip yoke and everything works just fine. I also switched over to a two piece drive shaft and ditched the aluminum factory one.

The affordable/cool route would be to have that rear end re sleeved with new axel tubes and then truss it, plus you would need to axels. The $5000-$12000 route would be a new rear end from one of the above mentioned companies.

This is what I ended up with. I would advise that while it was on my leaf sprung truck it reeked havoc on the leaf pack due to the added weight and width (it is wider then the factory axel putting more weight outside of the ubolts) of the rear end, at least it was in my case.

http://img.photobucket.com/albums/v335/dezertf150/F150/IM000951.jpg

http://img.photobucket.com/albums/v335/dezertf150/F150/IM000950.jpg

-Alex

[desertspeed]

Alex,

I saw your truck at H&M several times- I live just a few miles away and have their kit as well, so I stop in and say hi regularly. As far as the VSS, I have 4WD so I think that it is on the transfer case already???

Good info about the leafs though- I have plans to link it, but I need to cage it first. I was hoping the stock axles would last me long enough, but I added bumps before my recent Baja trip and that was a bad idea..... Hopefully the leafs will last for a year or so.

Oh well, that is off roading. No one said it was cheap.

I had no thought of using a junkyard 9"- I will go with at least a Currie or 9inchfloater.com, or break into the kids college savings and go with a Blitz or Tubeworks!

[Alex Paterson]

Alex,

I saw your truck at H&M several times- I live just a few miles away and have their kit as well, so I stop in and say hi regularly. As far as the VSS, I have 4WD so I think that it is on the transfer case already???

Good info about the leafs though- I have plans to link it, but I need to cage it first. I was hoping the stock axles would last me long enough, but I added bumps before my recent Baja trip and that was a bad idea..... Hopefully the leafs will last for a year or so.

Oh well, that is off roading. No one said it was cheap.

I had no thought of using a junkyard 9"- I will go with at least a Currie or 9inchfloater.com, or break into the kids college savings and go with a Blitz or Tubeworks!

Very cool, sounds like you have it figured out. Its funny, more people saw my truck before I ever did :)

Alex

[goofballracer]

my buddy will fully truss a 9" if you can get one for pretty cheap and he is a top notch welder at a very popular fab shop it might save you a couple bucks

[desertspeed]

my buddy will fully truss a 9" if you can get one for pretty cheap and he is a top notch welder at a very popular fab shop it might save you a couple bucks

PM sent...

[bajafx4]

Ford 9" removeable-carrier axle has been the axle of choice in many high performance applications for many years for a few reasons.

1) Ford 9" are of the removeable-carrier (banjo) design; the entire carrier assembly is removeable (hence the name) from the front of the center section, so you can easily work on the gears, differential, etc. on a bench rather than on the ground. Some race teams have multiple carrier assemblies pre-built, so if you explode a set of gears on race day it's quick and easy to replace them. Or sometimes their pre-built carrier assemblies will have different gear ratios to make gear changes easy.

2) With a removeable-carrier axle, the tubes and center sectionare all one welded piece compared to the integral-carrier style (8.8, 9.75, 10.25, etc.) where the axle tubes are pressed in to the center section. Less likelyhood of something separating or leaking.

3) The removable-carrier is a lot easier to strengthen because the real estate on the rear side of it is wide open for tubes, trusses, etc. With an integral-carrier axle you have the driveshaft connecting to the front and the bolt on cover in the rear, both need to be worked around. I'm not saying you can't strengthen a integral-carrier axle, but it's just not as easy... plus you're welding to different types of steel (rolled steel axle tubes and cast steel center section).

I would say that a Ford 9.75 is a better tow/haul axle, but a Ford 9" is the preferred axle of all types of racers.

[bajafx4]

http://images.fourwheeler.com/featuredvehicles/129_0710_06_z+2006_ford_f150+rear_axle.jpg

Trussed 9.75 axle. Not sure if that would have been enough to save you... your axle looks like a bannana. I would have duplicated what they did on the bottom on the top as well at the very least.

[desertspeed]

Thanks BajaFX4- that is exactly the explanation I was looking for. A new axle is on the way.....

[Dezertpilot]

My buddy ordered a .250 wall custom non-floating axle from Currie for right around 3k. It had custom everything, the thicker axle tubes, 35 spline chromoly axles, Wilwood disk brakes, the big studs, it was braced and I believe he got a deal on a 3rd member from Sierra. Since he has a single cab 1450 truck I would definitely step it up to a full floater from previous mentioned companies. I REALLY dig the new Blitz rear end, Householder is running it in his new TT also from Blitz.

[SoDrty]

I threw in a detroit locker, 4.88's and a super strong diff cover w/ support studs on my 9.75". I also box trussed it and made some standoff bump pads to keep the axle from getting smashed. I even have 2" wheel spacers at each end and I hammer the **[IMG]http://cdn3.race-dezert.com/forum/images/mexico-flag.png[/IMG] [I]¡Ay, caramba![/I]****[IMG]http://cdn3.race-dezert.com/forum/images/mexico-flag.png[/IMG] [I]¡Ay, caramba![/I]****[IMG]http://cdn3.race-dezert.com/forum/images/mexico-flag.png[/IMG] [I]¡Ay, caramba![/I]****[IMG]http://cdn3.race-dezert.com/forum/images/mexico-flag.png[/IMG] [I]¡Ay, caramba![/I]****[IMG]http://cdn3.race-dezert.com/forum/images/mexico-flag.png[/IMG] [I]¡Ay, caramba![/I]** out of it and it hasn't bent or let me down yet!!
no this isn't H&M or dirt-tech by any means but it's just an example of making what you have work w/o mega cash..;)

[matt_helton]

supercrew siickness.

http://i229.photobucket.com/albums/ee252/prerunner13/100_5221.jpg
http://i229.photobucket.com/albums/ee252/prerunner13/100_5202.jpg