Shafty torque twist questions..

[Darksiede]

Ok, I have an MRC and know all about torque twist on this little bugger..
It leads me to ask this in depth question:

My MRC spins both driveshafts the same direction, and every aftermarket tranny & T-case I've looked at does the same... Why don't transfer cases/trannies have counter rotating output shafts for the front and rear differential?

It would in theory help to cancel out some of the unwanted TT we deal with. It would offer the benefit of loading the differentials in the preferred method causing rotational down force on the tires front & rear. In current setups one diff has down force, the other has lift from the torque effect.

The differential would need to be flipped over, hub to hub, on 1 end of the rig, and you could do it so that you "clock" the diffs in the right way to create mechanical (rotational) down force on the tires.
Obviously it would be another gear in the tranny/transfer case, but I think it would be for the better. Trade a possible small hit in durability for the advantage of negating most if not all TT from the setup.
I know most/all shaftys use basically the same axle case front and rear, and the mount locations would likely be fubar and clocked into the wrong positions, thus making the manufacturers (or aftermarket) have to create a mirrored casing to allow proper geometry.

Is the reason this hasn't been done cost? Or are there flaws in my logic?

~Kev

[SMR 510RR]

Well if you do a proper four link it will take care of 95% of the TT you have on your MRC...I think that is a better solution

[alexchen86]

Originally Posted by Darksiede

Ok, I have an MRC and know all about torque twist on this little bugger..
It leads me to ask this in depth question:

My MRC spins both driveshafts the same direction, and every aftermarket tranny & T-case I've looked at does the same... Why don't transfer cases/trannies have counter rotating output shafts for the front and rear differential?

It would in theory help to cancel out some of the unwanted TT we deal with. It would offer the benefit of loading the differentials in the preferred method causing rotational down force on the tires front & rear. In current setups one diff has down force, the other has lift from the torque effect.

The differential would need to be flipped over, hub to hub, on 1 end of the rig, and you could do it so that you "clock" the diffs in the right way to create mechanical (rotational) down force on the tires.
Obviously it would be another gear in the tranny/transfer case, but I think it would be for the better. Trade a possible small hit in durability for the advantage of negating most if not all TT from the setup.
I know most/all shaftys use basically the same axle case front and rear, and the mount locations would likely be fubar and clocked into the wrong positions, thus making the manufacturers (or aftermarket) have to create a mirrored casing to allow proper geometry.

Is the reason this hasn't been done cost? Or are there flaws in my logic?

~Kev

That certainly does make sense. I was tearing apart one of my scale trucks running Tamiya axles and I was thinking about TT myself. It is already 4 linked front and rear so it's not a significant issue.

[ped453]

limit your shock, as above said 4 link, move your electronics lower instead of top center. This will almost eliminate your TT, best thing is, it's free

Hope this helps

[Terranaut]

Originally Posted by Darksiede

Ok, I have an MRC and know all about torque twist on this little bugger..
It leads me to ask this in depth question:

My MRC spins both driveshafts the same direction, and every aftermarket tranny & T-case I've looked at does the same... Why don't transfer cases/trannies have counter rotating output shafts for the front and rear differential?

It would in theory help to cancel out some of the unwanted TT we deal with. It would offer the benefit of loading the differentials in the preferred method causing rotational down force on the tires front & rear. In current setups one diff has down force, the other has lift from the torque effect.

The differential would need to be flipped over, hub to hub, on 1 end of the rig, and you could do it so that you "clock" the diffs in the right way to create mechanical (rotational) down force on the tires.
Obviously it would be another gear in the tranny/transfer case, but I think it would be for the better. Trade a possible small hit in durability for the advantage of negating most if not all TT from the setup.
I know most/all shaftys use basically the same axle case front and rear, and the mount locations would likely be fubar and clocked into the wrong positions, thus making the manufacturers (or aftermarket) have to create a mirrored casing to allow proper geometry.

Is the reason this hasn't been done cost? Or are there flaws in my logic?

~Kev

Just my take on it. The reason it isn't done is partly because of the added size, weight, complexity and cost of the transmission, and partly because it won't help when you need it most.

I think you are right in most of your thinking, it does seem logical, and I believe it would work in some situations. The problem is that it relies on equal torque at both axles to balance out, but that is not reality. Torque only goes where the traction is and is rarely balanced front and rear, and so you will still see the effects of torque twist, just that one end will be opposite to what it used to be.

This has been tried, there's pics of it somewhere on the forum. I think it was egressor, and if I recall correctly, he took it off again.

After a brief search my new ax10 chassis


Cheers.