Need torque twist help...pics included...

[Duuuuuuuude]

So I've got this super I built, and ever since its been able to move under its own power I've been trying to tune out the torque twist. Short links, long links, mounted low, mounted high, seperated and closer together, I've tried it all with various results.

I'm posting some pics in hopes that someone will be able to point me in the right direction.

The only way its been cured was to run it full droop, which is fine, except that I really need some belly clearance to get around most of the terrain around here. Too many sharp pointy rocks to have a belly scraper.

Front shocks are currently running 1/2 droop (springs inside and out), rears are full sprung, lots of preload on the rt rear. Shock oil is 40wt with a touch of 10k diff fluid. Springs are of unknown origin, but are the stiffest I have.

I've seen and downloaded the 4 link calculator, but was unable to get it to work right.

On to the pics...

 

[onefstsnake]

mount your shocks to the axles. but you would need longer shocks or modify the chassis.

 

[Duuuuuuuude]

mount your shocks to the axles. but you would need longer shocks or modify the chassis.

The last chassis I ran was long enough to do that, and it didn't seem to help. Running thicker oil and stiffer springs should give me the same results, I would think...

I've thought about whipping up some extensions so that the shocks will reach, still might...

 

[DiEzel]

Im no expert but from what ive seen people say countless times is "Double Triangulation" which is suppose to be the cure all...

But like i said thats what ive read, i still have torque twist and i am not double triangulated. Just a thought i'd share

 

[Duuuuuuuude]

Im no expert but from what ive seen people say countless times is "Double Triangulation" which is suppose to be the cure all...

But like i said thats what ive read, i still have torque twist and i am not double triangulated. Just a thought i'd share

Links are double triangulated. Not to a great degree, but they are.

 

[d-fly]

motor?

How many turns is your motor? depending on how thoses axles work the way that the drive shaft spins in the rear will lift one side. Adjusting both sides will through off how you rig works. you should just be able to put a stronger spring on the side that lifts of the ground. i dont know why you having such a big problem. you are doing to much work for such a simple problem.

 

[Duuuuuuuude]

How many turns is your motor? depending on how thoses axles work the way that the drive shaft spins in the rear will lift one side. Adjusting both sides will through off how you rig works. you should just be able to put a stronger spring on the side that lifts of the ground. i dont know why you having such a big problem. you are doing to much work for such a simple problem.

I run either a 65t lathe or a 13t brushless, depending on where I go to play. The 65 is for the heavy boulder bashing, the 13 is for the big long hills when I need some wheel speed.

Chassis twists to the right. If you notice in the pic above the right rear spring is preloaded nearly as much as the shock travel will allow. All others are adjusted to give the needed ride height.

 

[d-fly]

if the chassis twists to the right then you when the harder spring on the left. unless you are trying to say they right side lifts up means its twists to the left? you want to put the harder shock on that side. I also agree it would help if the shocks are mounted to the axles. Time for a new chassis that could help big time too

 

[Duuuuuuuude]

if the chassis twists to the right then you when the harder spring on the left. unless you are trying to say they right side lifts up means its twists to the left? you want to put the harder shock on that side. I also agree it would help if the shocks are mounted to the axles. Time for a new chassis that could help big time too

Chassis twists to the right when you are standing behind it, so the right rear squats, left front lifts.

Going to extend the shocks tonight or tommorow a.m.

Chassis is only a couple of weeks old. Other than not letting the shocks reach the axles, whats wrong with it?

 

[Duuuuuuuude]

Just for giggles I skipped the shock extensions and mounted the shocks to the axle. Lost nearly 2" of ground clearance and had to find a new temporary place to mount the battery, but we're just testing anyway, right?

So it seems to have helped a bit, but it still cranks over to the right. Not sure if the improvement is from the shock placement or my new super-low COG.

What I did notice was that it wasn't as bad if I tried the same climb backwards. Maybe I have too much weight in the front...

Tomorrow I'll swap the wheels around and see what happens, then go to town and find a tap that'll jive with the shock shafts.

 

[iwantoffroad]

upper links parrell to the ground and and if it not maybe even a little higher on the axle end.

also check out this thread sort through it and read it."thumbsup"
http://www.rccrawler.com/forum/showthread.php?t=54791

 

[Tanis]

You need to mount the shocks on the axles, but lengthen the chassis to keep them at the same angle. Also, raise the upper link mounts on the axles, to get more separation between the lowers and uppers, and then drill new holes in the chassis to lower your upper links more, to get less separation between your uppers and lowers and also bring the holes farther forward, closer to the lower link holes. 100wt oil in your right rear shock. That should get you in the ballpark.

 

[southernextreme]

with a shafty you'll always have torq. twist
i found that bent links rolled and added twist by not transfering the torq to the axle

 

[tuner]

Make the rear stiff and the front really soft on the suspention. Yeah that should work.

 

[joesbruiser]

with a shafty you'll always have torq. twist
i found that bent links rolled and added twist by not transfering the torq to the axle

With the proper setup torque twist can be almost completely eliminated if not done away with completely."thumbsup"

 

[Duuuuuuuude]

You need to mount the shocks on the axles, but lengthen the chassis to keep them at the same angle. Also, raise the upper link mounts on the axles, to get more separation between the lowers and uppers, and then drill new holes in the chassis to lower your upper links more, to get less separation between your uppers and lowers and also bring the holes farther forward, closer to the lower link holes. 100wt oil in your right rear shock. That should get you in the ballpark.

Like so?

 

[Reflection]

i found that bent links rolled and added twist by not transfering the torq to the axle

WHAT? :lol: You could run links with 5,653 different bends in them,they'll still transfer the same load to the axle as a straight link. The load doesn't follow the link,it's point to point.

Like so?

That should be better. Try to raise your upper axle mount a touch.

For better triangulation,move the uppers inside on the axle end. Then,notch out your skid and move the lowers to the middle of the skid.

 

[Tanis]

Like so?

Yes, but like Raptorman said, raise your links at the axle some more. And triangulating the lowers will help keep the axle in place throughout the suspension cycle.

 

[Duuuuuuuude]

Cool. Thanks guys, this is exactly the info I was looking for.

To move the uppers higher I'm going to need to build a mount for them, they're about as high as they will get at the moment.

Hopefully I'll have some progress pics by this evening. "thumbsup"

btw: I know this thread is focused on the rear of the truck, but I haven't seen any comments on the way the front links are placed, so should I assume they are in a reasonably good position?

also check out this thread sort through it and read it.

http://www.rccrawler.com/forum/showthread.php?t=54791

Believe me, I've spent hours reading nearly every comprehensive suspension thread I can find. I think I may have just taken in too much and got my noodle all twisted. Thats why I resorted to a noob-like "somebody point to the problem and tell me what to do" type thread...lol

 

[Jason S]

Try making the lower driver side link a touch longer then the passenger side.
work in my case.