Ford 7.5 tire question

[midget]

Will the 7.5 be able to handle 32" tall tractor tires? Im considering ditching my Ltbs that are on the back for something with more grip since I have no bed for rear weight but dont want to break axles until I can afford to start my 44/9 swap next winter...

 

[86ford]

the 7.5 will hold up just fine. As always I recommend you carry gear lube and spare shafts. I know of a few people off hand who have ran welded 7.5s with 33s-34s without failure.

86

 

[Mechanickid]

The ford 7.5 isn't given as much credit as it deserves, I have tried to break a few of them and failed. Usually something else will break before the axle in my experience.

 

[midget]

The front axle will break first if I use ltbs all the way around just wasnt sure if the extra bite is gonna make it snap it has a detroit locker in it right now. The truck is mostly pulling off the front axle so Im going to try and get some rear biite to make the d28 last a little longer .

 

[Shran]

I have run mine with 32's and 33's with no problems whatsoever. I would keep it but I already have a 31 spline 8.8 with discs. That and I do think the 7.5 may have trouble keeping up with a 302.

 

[midget]

well the tires I have are currently 34" LTBS but they actually measure 32" from ground to top of tire with 10 psi.

 

[86ford]

I have run mine with 32's and 33's with no problems whatsoever. I would keep it but I already have a 31 spline 8.8 with discs. That and I do think the 7.5 may have trouble keeping up with a 302.

The Mustang guys lock 7.5s and 28 spline 8.8s (same axles) all the time without failure. My brothers 93LX 5.0 lays down stripes (LS rear) and ran 12.7s in the quarter mile without any axle modifications. He is/was running 150 shot of nitrous, Cobra intake, 21? lb injectors, headers (not sure of brand), 2.5 inch exhaust (not sure of brand), etc. The only reason it is parked is he keeps killing the AOD tranny and cant pass emissions.

If I could remember his Dyno numbers I would post them.

86

 

[Shran]

The Mustang guys lock 7.5s and 28 spline 8.8s (same axles) all the time without failure. My brothers 93LX 5.0 lays down stripes (LS rear) and ran 12.7s in the quarter mile without any axle modifications. He is/was running 150 shot of nitrous, Cobra intake, 21? lb injectors, headers (not sure of brand), 2.5 inch exhaust (not sure of brand), etc. The only reason it is parked is he keeps killing the AOD tranny and cant pass emissions.

If I could remember his Dyno numbers I would post them.

86

Rocks are completely different than pavement though, and getting deep gears for a 7.5 is stupid for my application because it's so small. I do like the ground clearance though.

Not trying to argue or anything of course, just sayin. I have seen a couple guys break hardened shafts in a hi-9 setup so mine would be bound for failure eventually.

 

[86ford]

Rocks are completely different than pavement though, and getting deep gears for a 7.5 is stupid for my application because it's so small. I do like the ground clearance though.

Not trying to argue or anything of course, just sayin. I have seen a couple guys break hardened shafts in a hi-9 setup so mine would be bound for failure eventually.

I understand, you are welcome to play "devils advocate", typically that is my role. Everything WILL break, but IF you can get a 31 spline 8.8 disk brake axle for under 200 dollars you are starting off with a MUCH better axle.

I agree, rocks are MUCH different than pavement but keep in mind the torque numbers with a "built" 5.0 can put out are rather high. I do realize that a 4wd vehicle in low ranger puts out significantly greater torque than the same vehicle in high range. Keep in mind, to break a shaft it requires significant resistance & power(torque). Shaft failure requires the engine/gearing to be capable of twisting/snapping the shaft before enough force is created to spin the tire(s). In the case of a rear axle it takes SIGNIFICANTLY more force to break a shaft than with a front axle because it lacks the 4 yokes and 2 u-joints (at least 2). In most cases with locked axles you will need a significantly more stout front axle than rear because of the issues that come along with being able to steer a front axle. In most cases a locked d35 will fail before a locked 7.5 for the reasons mentioned.

86

 

[Sunk]

From what I've read, the weak spot in the 7.5 is the spider gears. If it's welded or locked, it should hold up fine.

 

[88rangerboy]

My 7.5 had held up fairly good for I've put it through. Like Sunk said the only problem I had were the spipder gears stripped and broke my s-clip in my trac-loc.

 

[MikeInIdaho]

The OP mentioned that he's running a detroit in his 7.5, which eliminates the axles' weak spot. He should be just fine running tractor tires with that setup.