Quaife ATB Front Splines

Hi,

I would like to fit a Quaife ATB to the front diff on my Gen 4 (and rear). My question relates to the number of splines I should specify for the front Quaife ATB, OEM 22 or 26? From what I understand the standard front half shafts should be fine, and if ever not then HD 22-spline aftermarket ones could be considered, so am I correct that there seems no good reason to go for a 26-spline and all the extra bits/expense upfront?

Thanks very much!

It all depends how hard you intend to push it off road 
26 spline shafts will be stronger 
But I'm sure both 22 and 26 spline use the same cv joint

Ultimately what tends to break shafts is wheel spin suddenly and violently stopping such as having a wheel in free air suddenly touch the ground. So as Jack says it really depends on how hard you are going to push, which in turn comes down to the terrain and your mechanical sympathy.

Surely the idea of having a locking diff is to stop the chance of having a spinning wheel in the air situation that can snap a shaft when tyre and earth re-unite.

Roger

Rodger you would be surprised how easy it is to lift a wheel in certain situations. Then there is bouncing on the spot on up hill climbs. 
Like Lambert says  (mechanical sympathy)
Also having really low gearing plays I big part 
 

If the suspension is capable of maintaining traction to all the wheels that are driven, then there is no need to add any form of traction control, but as Wild Bill wants to add Quaife Automatic Torque Biasing diffs to his Jimny I assumed that he periodically lifted a wheel and needed the Quaifes to control the inevitable spin out that will result. If you drive a track you will inevitably lift a wheel but Quaifes and the like will control the spin out so that when the wheel drops back it will not be spinning widely but will be controlled so that the damage you mention should not occur.

Roger

Yes, Roger, that's my thinking as well that I am trying to confirm. That coupled with the ALLGRIP Brake LSD Traction Control already there.

You misunderstand the operation of the quaife. They are not a locking diff they will spin if one wheel is in free air, they need some resistance on each wheel. Assuming there is some resistance they work astoundingly well to maintain even torque distribution. If you have traction control then it's debatable if you are not doubling up systems by adding the atb, the argument for is that with a wheel in the air the TC will work to provide the resistance the atb needs but the TC needs to see a wheel spinning to activate at which point that braking effort is already sending torque back across the diff so what extra is the atb adding. That's not to say that the atb doesn't add benefit in normal 4x2 road driving because it tightens up the general cornering dynamics to something like an old rwd escort, if you want that kind of thing.

Thanks for your reply.

Yes, I did some reading on driving with the Torsen diffs used in military HMMWVs, and I believe I now understand the difference between Brake Throttle Modulation as used in them compared to the on-off ABS traction control on the Jimny. It seems to me that if there is a wheel in the air spinning that when the ABS brakes that wheel the ATB will indeed send torque to the other wheel, but when the ABS braking ends, if still in the air, the wheel will begin to spin again and torque will be lost to the other wheel again and we begin again, whereas with BTM the brakes remain gently applied together with the throttle (robbing some torque of course but better than 0:100) until both wheels are on the ground and there is at least some traction on both.

This leads me to wonder if anyone now has any longer-term experience using the Chinese LR/WMD E-Lockers + Torsen diffs where you should have the benefit of Torsen on the road and fully lockable diffs when desired (I understand that there is some wheel movement required in the locking mechanism of an E-Locker before it actually locks compared to Air Locker, especially if changing vehicle direction).

Anyone?