What is Torque Twist (TT) and how to fix it.

[Manning]

The counter rotation driveshafts idea has a little bit of merit. But only if all 4 tires had equal traction.

TT shows up most while climbing. During a climb, there's very little weight on the front tires, and a bunch of weight on the rear tires. More weight on tires = more traction. (I know it's not a 100% proportional relationship)

So, with only a little weight on the front tires, there's not much traction for the front tires to work with, and the rear tires having a bunch of traction, well you can guess the result.

Counter rotating driveshafts is an interesting idea, but not worth the effort.

 

[Duuuuuuuude]

The counter rotation driveshafts idea has a little bit of merit. But only if all 4 tires had equal traction.

TT shows up most while climbing. During a climb, there's very little weight on the front tires, and a bunch of weight on the rear tires. More weight on tires = more traction. (I know it's not a 100% proportional relationship)

So, with only a little weight on the front tires, there's not much traction for the front tires to work with, and the rear tires having a bunch of traction, well you can guess the result.

Counter rotating driveshafts is an interesting idea, but not worth the effort.

I was having the same thought. All things being equal TT would go away, but things are rarely equal on a crawler.

 

[TotoRax]

Hello,

I had been interested in the counter rotation driveshafts idea, but after I build a lab crawler, the Experimental Bull'Ax , with front Bully axe and rear AX-10 axle :lmao: A stange project, but instructive :mrgreen: On this video, you can see a little TT at the end.
From this machine I concluded from it that the TT comes mainly from the rear axle.

 

[TSK]

What if...

A counter rotation unit was used

WITH...

a weight ring (to act as a gyro) on the front driveshaft (Ideally, up on the front diff yoke for both GC & effect since it will be as far forward as possible (so perhaps less mass is needed)?

 

[Duuuuuuuude]

IIRC gyros are illegal. Even if they aren't, I doubt that the driveshaft would spin it fast enough to do much good. You'd really have to get it zinging to have much of an effect. And it would have to lay flat.

 

[JeremyH]

Doesn't have anything to do with gears.

Oh really?

 

[Duuuuuuuude]

Oh really?

It does, but not in the way he mentioned.

 

[JeremyH]

Proof is left as an exercise for the student.

Wow...that line brings back some memories....:lol:

 

[JeremyH]

It does, but not in the way he mentioned.

Oh really?

 

[Duuuuuuuude]

Oh really?

Really.

 

[JeremyH]

Really.

Interesting. I must have missed when the torque twist creation experiment was performed....

 

[Duuuuuuuude]

I guess so.

 

[JeremyH]

I guess so.

Link?

 

[Duuuuuuuude]

Link?

 

[JeremyH]

That empirical scientist looks more like a tranny than a scientist.

 

[Duuuuuuuude]

That empirical scientist looks more like a tranny than a scientist.

You asked for Link, I gave you Link. I don't draw 'em, I just post 'em.

 

[TSK]

Are you certian one of these on the driveshaft won't help?

 

[Duuuuuuuude]

Are you certian one of these on the driveshaft won't help?

My bad, I thought you meant "gyro", not "gyro".

Dunno. Guess you could try it.

 

[stanmondz]

i had a nice "test" typed out last night, then henry county lost a power sub station and the power went out before i was done typing


ill try it again. TT starts with the motor, and is made worse my resistance to movement.
heres my test. if you have a rear drive car/truck, go start it up. now rev it a few times. what happens? front left lifts,rear right spuats= torque twist, no gears,tranny,or drive shafts involved

do the same in a front wheel drive car with a transverse engine. no twist, maybe a slight back and forth rock

now take the rear drive car, drop it in gear and hammer it. it will twist worse because the engine is pulling up on the left motor mount same as it did in park/netural. but now the forward movement is lifting the front and making it lighter so more weight is pushing against the rear springs, but at the same time, the chassis is twisting to the right because of the engine torque and putting a lot more weight on the right rear spring than any of the other 3 springs. its gonna compress more because any one spring isn't made to hold most of the weight by its self

FWD cars wont twist, just loose traction on there drive wheels because the weight is moving to the rear of the car

 

[Hardline]

Tests are good. Is the RF being pushed into the air by some torque reaction coming through the driveshaft, or being pulled into the air by a twisting chassis?

What if we do the angle board thing with the rf shock disconnected. If the drivetrain torque is twisting the axle up, it still will. But if the tire is being pulled up by the chassis, it will now stay on the board.