Wild horses wrap trap?

[rocknhorse76]

I think it's a great but like I mentioned earlier, only on vehciles with "limited" suspension movement. The RS setup works great for stopping rear end rotation or wrap as we have called it for long travel suspensions.

Like Broncobowsher said above, GM used something similar on their F body cars. I am building one similar to those for use as a 3rd link on my Shorty build but Shorty like all F body cars has very limited vertical travel and that's why it works so well. He was also spot on about leaf springs turning into an S shape when torque is applied. Took me a long time to realize that's why I kept breaking rear springs. Also used to snap rear leaf spring hangars almost every year. Compression and tension forces on the rear end is pretty amazing.

TS posted up about the leaf springs essentially being twisted into an S and being the bottom "link" about 20 yrs ago and that was my clue as to what was going on with my broken leaf springs every few years.

Yeah, we probably would’ve been linking the rear in mine if the transmission didn’t decide that it didn’t like my 408 lol.

 

[nvrstuk]

Definitely miscommunication.

So your last 2 sentences. Would this be for a car type suspension or something for 14-18" of suspension travel? I can't picture it.

 

[Broncobowsher]

Definitely miscommunication.

So your last 2 sentences. Would this be for a car type suspension or something for 14-18" of suspension travel? I can't picture it.

The limit strap idea would be for a short travel off-road rig. Maybe car?
It is just an idea. Something besides a solid link. Stays out of the picture until it is needed. Think Wrap trap but a strap instead of a tension rod.

 

[stupidboy]

Now this is the discussion I was looking for

 

[Yeller]

Pat, for your uses, what you have is fine and more than adequate. I never had issues either until I went to a doubler 25ish years ago and started going hard enough that I was looking at carrying a spare leaf spring in the truck becauseI was bending or breaking a main leaf every time out. Linked it and never looked back. I’m imagining your uses are similar and probably even easier than my leaf sprung J Truck, which has no torque management device. It probably should have one but currently does not, it wheel hops terribly, but the leafs are long and sooofffft.

 

[73azbronco]

I think there is a little mis-communication. The shackle (something to allow the small amount of for/aft travel) is needed with the torque arm.
The wrap trap is not an arm, it is a link. That can't have a shackle. It works by limiting for/aft travel.
My comments about not having a shackle are in reference to stupidboy's question about a shackle limiting suspension while he is inquiring about the wrap trap.
Only the wrap trap should NOT have a shackle.
The ruff stuff or Duff style arms SHOULD have a shackle.

More boring history stuff. Back when vehicles had torque tubes (before exposed driveshafts) the rear axle had a torque arm that pivoted off a ball around the single U-joint at the back of the transmission. This is very much like the torque arms. The leaf springs (when used a pair of parrallel springs and not a single transverse spring) would have shackles at front and back. This was because the pivot and thrust for the rear axle were at the back of the transmission. A solid hanger would bind. When open drivelines (What we think is normal today, driveshaft with 2 U-joint locations and telescopes) came to scene the front shackle on the leaf spring changed to a simple spring hanger. The axle forces now go to the frame instead of the back of the transmission. The only thing that still uses the old school torque tube design (that I know of) is spring cars. They do away with the transmission and just a direct drive to the back of the engine with a sliding in/out engagment. I find it amazing how much modern sprint cars have in common with cars from the 30s.

As for the wrap trap. The only OEM application I know of for this design goes back to the late 60's AMC. They used a pair instead of a single. But they were traction bars on the higher power AMX and Javelins. Top of the axle pull link.

The torque arm goes back to the '60s and can be seen as an evolution of the pinion snubber. A rubber bump stop added to the front of the pinion that would hit the floor pan on hard acceleration to prevent pinion rise from the spring wrap. The off-road world just grew it out to a much longer arm and captured the front of the arm in a pivoting shackle arrangement instead of a rubber bumpstop smacking the floor. We have too much wheel travel for the floor smacking snubber to work.

I've had thoughts of using a limit strap like the wrap trap. Top of the axle housing to the frame. Under acceleration it would pull tight.

OK, full disclosure, as in, back before open driveshafts, you stated vehicles with torque tubes, we called those vehicles Model T's. More fun history, it had what we would consider a 4 link suspension. The enclosed tube was used as a structural member for the axle. They had not come up with leaf springs as we know them today.

 

[gnpenning]

The 3rd gen F body had mounting boss on the diff. When they first came out they had been over torqued from the factory causing the front pinion bearing area to distort.

 

[Broncobowsher]

The closed driveline (torque tube) lasted through the early 50's. Watching some Steve Magnati Junkyard crawls and he was going over the history of them.
As for the Model T, they actually flex out pretty good

 

[73azbronco]

thats a 4 link for ya! And how else did you expect them to cross the rubicon back in the 1900's?

 

[Yeller]

Everything flexed on those cars and you if rolled over you and a buddy could roll it back over