Quaife ATB differential

The ATB blurb from an MG web page.

mgaguru.com/mgtech/rearaxle/ra302c.htm

Jezz wrote: The ATB blurb from an MG web page.

mgaguru.com/mgtech/rearaxle/ra302c.htm

Great link, thanks. This is the concept I was trying to explain less eloquently in my previous post:

"These can be designed with torque bias of 3:1 or up to 5:1. So if one wheel begins to lose traction the other wheel can receive up to 5 times as much torque as the one that is slipping. It also has the advantage of being able to transmit nearly all of the propshaft input torque to the wheels, proportioning torque appropriately up to the point where both wheels might spin at the same time.

Unfortunately five times zero is still zero, so when one wheel hits a patch of wet ice it will still spin, and the other wheel will be limited to five times the torque as the one on ice. This works well as long as the low torque wheel still has some grip and some available torque, but if you lift a wheel in a fast turn it will immediately revert to zero torque all around like an open differential."

So useful where there's partial grip but no help if you get stuck with one wheel in the air, where a full locking diff would be needed.

Old thread but great read.

So the Jimny can now have the same type of diff as the Military Humvee, at least in one axle.

Any one know what the torque Bias is in the Jimny specific Quaife ATB differential? 3:1 and 5:1 are quoted. Hopefully it's a 5:1.

A friend in the US military, said that standard Humvee training practice was to apply the brake slightly in situations where forward progress was interrupted by loss of traction. The multiplication of the breaking torque to wheels with some traction remaining was not explained to recruits. Just apply plenty of throttle and enough brake to get in motion. this does strain the transmission somewhat.

I think the Quaife with a dual hand brake mod would be an awesome combination for those who spend 90% on road but want to go hard off road. On the occasions that the dangling wheel is the issue brake it and 100% of rear axle torque is now available at the load bearing wheel. With a bit of practice it wouldn't be much less involved than locking and unlocking the 'Gold standard' ARB.

Cheers,

Grogey

Hi Folks,

Old thread but I had some quick questions around this.

I own a Maruti Gypsy which is the current in-production version of the Suzuki Samurai LWB413 manufactured in India.
While you folks are Jimny owners - do you know if the 2018 Jimny use exactly the same axle/gears as the Samurai and whether I can fit this QDF3P Quaife Suzuki Jimny ATB differential unit into my Gypsy? Or do the Jimny's use a different gear/axle ratio than the Samurais? I think mine is 26 spline 6.9" gear at the rear and 22 spline at the front.

I dont off-road, just want to prep my car for remote mountain trips somewhere down the line with bad to non-existent roads without getting stuck easily.

Thanks for your inputs around this.

Lambert wrote: Except that off road with a wheel in the air you have the opportunity to apply a little bit of hand brake or left foot brake to give resistance to the spinning wheel and essentially trick the atb into sending drive where you have grip. It takes a degree of skill and understanding to master but in essence its the same operation as terrain response in a modern semi locking land rover but without the computers.

In the case of the Gen.4 the automated 'BLSD' or torque biasing brake system will do this for you. Making the addition of a Torsen LSD an absolute weapon.

A quick bit of googling and I ended up here <eBay Link>

HTH

The Gypsy rear axle has 6.9" Gear with 26 splines. Is that the only spec I need to look at for compatibility or do I need to look at other things? When I spoke about this to a local garage I was told I need to look at other things like like count of teeth in the ring gear or mounting pattern - but I am not convinced on that. I am not an engineer and I have just starting reading a textbook on Drivetrains gear ratios and transfer cases etc., hopefully by this weekend I will have all the key terms understood and memorized to be able to name all the parts in the drivetrain and their function.

But in the meantime I would like to keep some conversation going and take your help along the way on this topic, and trigger some new findings and learnings.

Edit: it looks like 10 vs 12 nuts/bolts are also important to consider?
Thanks

GObble - In answer to your PM, there was only basic advice about ensuring the backlash was set to factory limits. No real fitting instructions as it were....

In your position, I would contact Quaife directly with the factory spec's of your axle and ask the question about suitability, directly. They are a helpful bunch and happy to talk to those with little technical knowledge (me....) and lead you by the hand....

A normal transmission shop fitted my diff with four hours labour.

They are a cracking piece of kit and really do transform the chassis dynamic of any car they are fitted to, on a road biased car they will provide the best performance of any differential, in my opinion.

I am yet to find a situation whilst driving off road where it has let me down either....

sniper

I fitted an Eaton (now Detroit) Trutrac helical gear style LSD to the back axle of a Landcruiser and can vouch for there effectiveness both on and off a sealed surface. In my opinion they are far better than a locking diff. that requires driver input.

Roger

Thank you for the replies. I just got a reply from Jimnybits a few mins back telling the same thing.

Another thing - Do you think the factory axle shaft is strong enough to handle the 80% torque bias on one side alone? I guess its not going to load the axle like a fully locking diff but still.. my car has done 80k Kms and some things are going to be worn out a bit.

I am thinking I will get some of those chromoly off-road axle shafts from the U.S. There is even a 26 spline conversion for the front - which got me thinking - what will be the impact of putting the ATB LSD on both front and rear? Is there a risk of over/under steer on high-speed turns or any unpredictable change in handling and steering behavior if put it in the front?

FYI these are the Gear Axle ratios for my MG413W:
Gearing:

---

1st 3.652
2nd 1.947
3rd 1.423
4th 1.000
5th 0.795
Reverse 3.466

TC-High: 1.409
TC-Low: 2.268

Axle: 3.73:1

---

Am I correct that only the Axle ratios matter and rest is irrelevant and will not affect anything - even if say the Jimny U.K variant this product was tested on had slightly different gear ratios? I believe the Axle ratios are the same for both so its all good ..?

PS: Yes the Eaton was my original wishful choice because it was not available for the 26 spline Suzukis. I read a lot about it still as I dreamt ... Then I chanced upon this thread and discovered the Quaife ATB product.