Would You Rather: SAS or lift, discuss amongst yourselves

[Littlebeefy]

Greetings,

I have an 85 Bronco that I did a straight axle swap on about 5 years ago.

I used the long arm kit from James Duff. I live in Michigan and have a Western snowplow on my truck. The TTB did weird stuff when I carried the blade in the up position,the tops of tires would tip in. Going down the road the blade is hanging a few hundred pounds out front running on the inside edge of the tires was squirrelly.

My swap used a high pinion dana44 from a 79 F150. My original front driveshaft was reused.

The Duff kit does require a few inches of lift. Did have to cut the bottom off the crossmember. Zero regrets.

A side note about welding to these frames, Im pretty sure that I was told that welding these frames causes cracking. All my Duff parts were bolt ons.

For my application, love it! I am doing it to the one that I am building now.

Curt

Hi Snowpony,

I'm glad to hear you liked it in your application. Why did you decide to use the Dana 44 instead of the Dana 60?

There are several kits out there, many purportedly "bolt on". The Duff system you mentioned looks pretty nice (and I've heard good things about it from at least one other person who has actually used it) and it seems there are some pretty decent additional options:

https://dufftuff.com/product-category/full-size-bronco/sas-swap-packages-level-1-monster/

https://broncoair.com/sasInfo.php

https://www.skysoffroaddesign.com/collections/80-96-bronco-f-150-suspension/products/ford-sas-bf150?variant=19048852548

https://desolatemotorsports.com/shop/suspension/front-suspension/bronco-f150-4x4-straight-axle-conversion-kit-coming-soon/

https://protofab4x4.com/product/fullsize-sas-kit/

 

[ArdWrknTrk]

Hi Snowpony,

I'm glad to hear you liked it in your application. Why did you decide to use the Dana 44 instead of the Dana 60?

There are several kits out there, many purportedly "bolt on". The Duff system you mentioned looks pretty nice (and I've heard good things about it from at least one other person who has actually used it) and it seems there are some pretty decent additional options:

https://dufftuff.com/product-category/full-size-bronco/sas-swap-packages-level-1-monster/

https://broncoair.com/sasInfo.php

https://www.skysoffroaddesign.com/collections/80-96-bronco-f-150-suspension/products/ford-sas-bf150?variant=19048852548

https://desolatemotorsports.com/shop/suspension/front-suspension/bronco-f150-4x4-straight-axle-conversion-kit-coming-soon/

https://protofab4x4.com/product/fullsize-sas-kit/

I imagine because the D44 has the correct 5 lug pattern to match the rear axle, takes a 15" rim and coil springs, unlike anything over #8,500.

... The F-350 where you'd find a D60 front axle.

[Littlebeefy]

I imagine because the D44 has the correct 5 lug pattern to match the rear axle, takes a 15" rim and coil springs, unlike anything over #8,500.

... The F-350 where you'd find a D60 front axle.

Honestly, Jim, I’d sort of taken for granted that the 8 lug rear end would be more desirable and worth the trouble of installing with a set. Come to think of it, though, other than more options for wheels there isn’t really any benefit to the SD rear axle on such a short wheelbase truck, is there? Can you think of anything else that would make it worth the effort?

[ArdWrknTrk]

Honestly, Jim, I’d sort of taken for granted that the 8 lug rear end would be more desirable and worth the trouble of installing with a set. Come to think of it, though, other than more options for wheels there isn’t really any benefit to the SD rear axle on such a short wheelbase truck, is there? Can you think of anything else that would make it worth the effort?

Super Duty, as in '99>?

Metric lug pattern?

My personal opinion is that these much bigger axles are much more unsprung weight, and would really harm bump response.

My truck tares at almost 6,700#, I can't imagine how harsh it would be in a Bronco.

[Nothing Special]

Super Duty, as in '99>?

Metric lug pattern?

My personal opinion is that these much bigger axles are much more unsprung weight, and would really harm bump response.

My truck tares at almost 6,700#, I can't imagine how harsh it would be in a Bronco.

Like Jim, I don't want any additional height on my F-250 so I wouldn't do either. In fact, I think I'm going to be looking for a less rusty crew cab soon, and if it ends up being an F-350 I very well might swap a TTB into it to lower it.

However, to follow the ground rules... If I did want to lift my F-250 I'd do a SAS. It's a simple bolt-on with stock F-350 parts. And like Gary, I think the leaf spring TTB suspension is a terrible design (yes, I know I just said I might put it on an F-350...).

I probably would not do an RSK however, unless I wanted even more lift. Yes it would likely improve the ride. And if I DID want more lift that the ~2" an SAS would give I'd do an RSK.

On an F-150 / Bronco I'd definitely lift the TTB suspension. In fact I did that on the '95 F-150 I used to have. I think that gives better ride and handling than a solid axle.

The only reasons I'd want a solid axle on an F-150 is if I was going to use it for plowing, or if I was building it into a rock crawler or mudder and wanted big tires and stronger axles. Then if I was doing it for a plow I'd go with a Dana 44 for the lower weight = better ride and handling. Or if it was for off-roading I'd use a Dana 60 and probably a GM 14 bolt in the rear, giving up ride, handling (and affordability!) in favor of strength.

[Gary Lewis]

Like Jim, I don't want any additional height on my F-250 so I wouldn't do either. In fact, I think I'm going to be looking for a less rusty crew cab soon, and if it ends up being an F-350 I very well might swap a TTB into it to lower it.

However, to follow the ground rules... If I did want to lift my F-250 I'd do a SAS. It's a simple bolt-on with stock F-350 parts. And like Gary, I think the leaf spring TTB suspension is a terrible design (yes, I know I just said I might put it on an F-350...).

I probably would not do an RSK however, unless I wanted even more lift. Yes it would likely improve the ride. And if I DID want more lift that the ~2" an SAS would give I'd do an RSK.

On an F-150 / Bronco I'd definitely lift the TTB suspension. In fact I did that on the '95 F-150 I used to have. I think that gives better ride and handling than a solid axle.

The only reasons I'd want a solid axle on an F-150 is if I was going to use it for plowing, or if I was building it into a rock crawler or mudder and wanted big tires and stronger axles. Then if I was doing it for a plow I'd go with a Dana 44 for the lower weight = better ride and handling. Or if it was for off-roading I'd use a Dana 60 and probably a GM 14 bolt in the rear, giving up ride, handling (and affordability!) in favor of strength.

Actually, with stock rear suspension my SAS/RSK/SD spring swap slightly reduced the liftover height at the tailgate. That's cause the front came up and the rear of the tailgate rotated down a bit. Not much, but it sure didn't get higher.

[ArdWrknTrk]

Actually, with stock rear suspension my SAS/RSK/SD spring swap slightly reduced the liftover height at the tailgate. That's cause the front came up and the rear of the tailgate rotated down a bit. Not much, but it sure didn't get higher.

As it it would if you had also installed the 350 blocks on the rear.axle.

I understand how the rotation about the rear axle centerline is going to reduce gate height by the proportion of the two distances.

133" V something like 48"

[Gary Lewis]

As it it would if you had also installed the 350 blocks on the rear.axle.

I understand how the rotation about the rear axle centerline is going to reduce gate height by the proportion of the two distances.

133" V something like 48"

Yep - Didn't and don't want the taller 350 blocks. Was thrilled when the front end came up level with the rear.

[Littlebeefy]

Yep - Didn't and don't want the taller 350 blocks. Was thrilled when the front end came up level with the rear.

It seems nuts to me but what it sounds like is if you wanted improvement in off road ability in the Bullnose Bronco, a vehicle that was ostensibly sold for its off road prowess, the best way to do it (back when it was new) was to replace the front end with the 78-79 Bronco front axle. Huh? Great job, Ford. Way to move the state of the art.

Clearly Snowpony has it down to a science but now I understand why.

[Gary Lewis]

It seems nuts to me but what it sounds like is if you wanted improvement in off road ability in the Bullnose Bronco, a vehicle that was ostensibly sold for its off road prowess, the best way to do it (back when it was new) was to replace the front end with the 78-79 Bronco front axle. Huh? Great job, Ford. Way to move the state of the art.

Clearly Snowpony has it down to a science but now I understand why.

Now you are back to the question of what you want to do with the truck. If you want to do the Baja 500 you'll want the coil-sprung TTB's as they give the most compliant suspension and keep the tires planted. They keep the un-sprung weight down on each tire and are more supple. Lots of people still swear by them, although there are those that don't understand them that swear at them.

But nobody swears by the leaf-sprung TTB's.