RandallDee
Senior Member
RandallDee - What are your preferences for the TTB? I can see articulation and ride quality as its two biggest pluses. My issue with it is the alignment changes constantly as the suspension cycles and in my experience it causes funny tire wear.
I live in the city. And a most of the time when I take a trip, it involves a 4 or 5 hour drive on the interstate or highway getting to where I'm going. So I wanted a van that I didn't have to fight and felt comfortable driving in those conditions at highway speeds. I'm also not a fan of a big lift and I didn't want a van that required a 6 inch lift just to obtain an optimal turning radius. I think it all comes down to our individual uses.
If I did a lot of rock hopping trail type stuff, I might lean more toward a Ujoint type build. But I don't. My FWD needs are pretty light. I drive on gravel bars and use FWD to pull my raft out of the river and generally pretty light use. So a lower stance and good highway manners were a higher priority for me.
Before I decided on a TTB 50, I read all the stuff about the original Ford TTB's and how they chewed thru tires. My understanding is that the weak link in the originals were the radius arms. The ones on my Agile build are pretty beefy. My conversion is 3 years old and has over 20k miles on it and my tires are wearing evenly without any issues so far. I don't have any issues with my alignment changing constantly.
I saved the link to this post by the late Ramsey because I always thought it was one of the better explanations I found. Sometimes I really miss him around here. But here is his explanation....
http://www.sportsmobileforum.com/fo...mb-vs-quigley-vs-advanced-4x4-vs-10389-2.html
Your Bronco and F150s (1/2 ton PU) use a Dana 44 Twin Traction Beams. I have seen a few odd ball versions of the D44 TTB that are very rare and I have no explanation for them but 99.9% of them are basically the same. The weakness of the stock D44 TTB is the stamped steel radius arms, they can bend under minor impact and they are too short, resulting in excessive caster change. The Traction Beams themselves are strong and the spindles, ball joints, u-joints, axles, lock hubs are essentially the same as any straight axle Dana 44 used in Ford, Chevy, Jeep... applications, mostly 1/2 ton vehicles. There are straight axle Dana 44's used in 3/4 ton applications by the same manufacturers, the difference being that they use larger spindles, bearings, steering knuckle, hub... in 8 lug but the same drive axles and u-joints.
Ford did the same thing in some F250 (3/4 ton) TTB trucks - they use a Twin Traction Beam that uses a D44 differential but with larger spindle, inner bearings, steering knuckle... in 8 lug but the same drive axles, u-joints and lock hubs as the lighter D44. These Twin Traction Beams are different in design than the D44 TTBs and the beams and are not interchangeable as the lengths are different. I consider these to be a hybrid "Heavy Duty D44 TTB" and not what I would build off of.
All of the same manufactures at one time or another used a straight axle Dana 60 (there are way too many configuration of the D60 to get into) which is considered to be the "heavy duty" axle of choice in 3/4 an 1 ton on up trucks. These D60's use bigger components than the D44, most importantly the R&P, drive axles, u-joints, spindles, wheel bearings, ball joints, lock hubs...
The Dana 50 Twin Traction Beam used by Ford in 3/4 and 1 ton trucks uses these same D60 sized components. The drive axles, u-joints, spindles, wheel bearings, ball joints, lock hubs... are the same size as the D60s of the same vintage (I say that because the new D60s use unit bearings and are somewhat different) and are just as strong. The D50 TTBs are different in design than the Bronco and F150 D44 TTBs (different lengths) and are not interchangeable.
All of the Bronco and F150s (1/2 ton PU) Dana 44 Twin Traction Beams are suspended with coil springs and located by radius arms. The F250 and F350 with the "Heavy Duty D44 TTB" or the stronger D50 TTB are suspended with leaf springs and have no radius arms as the leaf springs locate the beams.
For years we have been building, prerunning and racing Bronco and F150s with modified D44 TTBs with 37" tires and 600 HP and they hold up terrifically. The simplest modification is relocating the lower Ball Joint outward to change the camber and welding on 2 or 3 tube radius arms that are much longer to reduce caster change. These simple modifications yield 17 inches of front wheel travel on a Bronco with about a 4 inch lift. More complicated builds include lengthening (widening) both Traction Beams from 2.5 to 5 inches to increase track width and reduce camber change.
On my SMB E350 EB, I installed a Dana 50 TTB system using custom tubular radius arms welded to stock D50 TTBs from a 1 ton F350. It is every bit as strong as a Dana 60 in my opinion and has the ride comfort of independent wheel movement. I get 5 inches of bump travel and 7 inches of droop for a total of 12 inches and at a lower ride height. I'm running BFG LT315/70R17 which is reported to be 34.5" dia.