Ford 9" questions

[shockseals.com]

What is the max width, wheel to wheel that can be put on a steel fendered bronco with stock wheels and 35x12.5 tires?

What is the max size rotor that will fit in a 15" stock alcoa?

Is there a preferred spline count on the axles for largest sleection of diff units out there?

What is the preferred diff? Spool is not an option.

Is there a preferred 3rd member?

I see high pinion...is the strength = to regular pinion? Seems like a good idea for increased droop since driveshaft is limiter.


I dont know much about 9" rear ends or rear ends in general for that matter. I do know I want a full floater 9" if I am going to swap the rear end. Preferrably a full fabbed chromoly housing like one from Dirt Tech or similar.


I have access to a Cone chromoly housing, cone hubs, 300m axles but I believe it is 67" WMS to WMS but the snouts arent on yet and I could cut the tubes down a little bit and have the axles shortened a little bit. Not sure if I want to go with a standard housing since the price isnt a steal, its just a good deal.

[Phoenix0783]

My rear is 65 1/4" wms to wms. I have 8" wheels with 35x12.5x15 bfg km's and there's a bit of tire clearance at the top of the wheel opening, but not really that much. My third member is the old c7aw one, which is kind of weak relatively speaking to other 9" third members.

[philofab]

What is the max width, wheel to wheel that can be put on a steel fendered bronco with stock wheels and 35x12.5 tires?

With stock alcoas you would want 66". The stock axle is 65" and it causes tires to rub on the inner fender well. You will need to roll the inner edge of the fender to keep from hitting the outside edge of the tire.

What is the max size rotor that will fit in a 15" stock alcoa?

11" / 11.5 depending on caliper location and style.

Is there a preferred spline count on the axles for largest sleection of diff units out there?

35 spline if your build an axle from scratch.

What is the preferred diff? Spool is not an option.

Detroit if you don't mind them on the street, clutch style limited slip if you do.

Is there a preferred 3rd member?

Aftermarket Nodular

I see high pinion...is the strength = to regular pinion? Seems like a good idea for increased droop since driveshaft is limiter.

High pinion has oiling issues especially if you have a pinion angle that points upwards.

I dont know much about 9" rear ends or rear ends in general for that matter. I do know I want a full floater 9" if I am going to swap the rear end. Preferrably a full fabbed chromoly housing like one from Dirt Tech or similar.

Full floater is the way to go.

I have access to a Cone chromoly housing, cone hubs, 300m axles but I believe it is 67" WMS to WMS but the snouts arent on yet and I could cut the tubes down a little bit and have the axles shortened a little bit. Not sure if I want to go with a standard housing since the price isnt a steal, its just a good deal.

You might be axle to get away with 67" if you flare the quarter panels a little, I have seen it done to some success on Broncos.

[Polarcub]

The econoline axle will clear with pulled fenders for a 12.50 its 1.5" wider on each side. As far as splines I feel 31 is adequate for 99% of the users out there but 35 is the accepted "best" for the 9" you will need custom axles to get 35" the econolines are 28 spline I may run them once I get this housing put together but I think the 31/35 would make me feel better. Spline count rally depends on you and the right foot.

[Deleted Account]

why no spool? they are nicer to drive on the street then a detriot. and you can go 40 spline.

[shockseals.com]

why no spool? they are nicer to drive on the street then a detriot. and you can go 40 spline.

Short wheel base, terrible manners on the highway, tire wear, etc...

Detroit not my first choice either. Electric locker would be ideal.

[philofab]

why no spool? they are nicer to drive on the street then a detriot. and you can go 40 spline.

Short wheel base, terrible manners on the highway, tire wear, etc...

Detroit not my first choice either. Electric locker would be ideal.

I've never noticed a spool or Detroit on the highway, the spool kicks my ass in parking lots though especially when I'm towing the boat.

[Polarcub]

I have a detroit in mine (8.8) and dont really notice it. On the highway I do notice it a bit and it took some getting used to but tolerable. The next one will have a spool over the detroit based on the cost difference

[shockseals.com]

spool or detroit not very safe in snow either...

[philofab]

spool or detroit not very safe in snow either...

An ARB might be your best option, they are very heavy though.

[Nick]

spool or detroit not very safe in snow either...

An ARB might be your best option, they are very heavy though.

And very $$$

[shockseals.com]

spool or detroit not very safe in snow either...

An ARB might be your best option, they are very heavy though.

Prob end up with a posi. Not a fan of ARB either.

[philofab]

spool or detroit not very safe in snow either...

An ARB might be your best option, they are very heavy though.

Prob end up with a posi. Not a fan of ARB either.

Factory Ford Trac-locs work quite well if you add another friction and steel while rebuilding. This is only an option if you decide to run a 31" axle.

[BDKW1]

True-trac and some good 31 spline axles. I hate Detroit's with a passion. I would rather run a spool that one of those erratic POS's.........

[hobbyturnedobsession]

I've got a detroit locker in mine. The only time I really notice it was on the highway, but I got used to it really quick. Trac locs are okay, but a locker I think is better. I've noticed with a trac loc it doesn't lock in as well.

[Seattle FSB]

I went with the Currie F9 w/full width back brace. 65 1/4" WMS to WMS, Nodular 9+ third member, 35 Spline, WaveTrac Differential. Had to settle for Explorer 11" disc brakes to fit in my 15" Alcoa wheels, but would have loved Wilwood or other larger discs. I also considered a High Pinion 9, but they carry 20% loss in gearset strength due to the reverse rotation design as they are designed for front end applications. By the way, the WaveTrac is a very cool 35 spline auto-loading differential which carries a lifetime warranty including off-road and racing applications.

http://fullsizebronco.com/forum/showthr ... 431&page=3

Axels
Style: Performance, 1541 Forged Alloy, 1.5" Diameter
Type: Tapered T&E
Spline: 35@60°
Pattern: 5 on 5.5 Inch
Stud: 19/32 Disc x 1/2-20
Register Diameter: 2.800
Driver Axle: 30.889
Passenger Axle: 32.766

Housing
Style: F9 Fabricated Housing w/3.0 Inch Tube
End Type: 9+ Torino/Large Bearing
Brackets: Loose
Housing Width: 59.78
Driver Housing: 25.254
Passenger Housing: 24.506
Driver Tube: 21.227
Passenger Tube: 20.479

3rd Member
Style: 9 Inch Ford
Ratio: 4.56S
Spline: 35@60°
Differential: WaveTrac
Yoke: 9+ 1350
Case: 9+ Nodular Race
Pinion Support: 9+ Race
Pinion Offset: 1.25

Overall Dimension: 65.25"
Full Width Back Brace
U-Bolt Support Plates
Loose Shock Mounts
Lokar Universal Parking Brake
Wilwood Brake Proportioning Valve

Hardware
RuffStuff 5/8" Grade 8 U-Bolts
RuffStuff 3/8" Steel Spring Plates
RuffStuff 1/4" Thick 3" x 8" Antiwrap Spring Perches

[shockseals.com]

I can get a killer deal on that same setup but its not a full floater

[ChaseTruck754]

Housing
Style: F9 Fabricated Housing w/3.0 Inch Tube
End Type: 9+ Torino/Large Bearing

Based on the above it doesn't look like what he has was a full floater either. Looks like a semi float to me.

[Deleted Account]

WHAT IS A WAVETRAC????? who sells them?

[Seattle FSB]

Wavetrac®: Gives you quicker acceleration and faster cornering by driving both drive wheels instead of just one. And, it offers improved no-load performance when compared to other helical gear differentials on the market.

AutoTech Driveline
http://www.wavetrac.net/technical.htm

Moser Engineering
http://www.moserengineering.com/differe ... pline.html

California Dealers
http://www.wavetrac.net/dealers.htm