55 replies to this topic

[PoolGuy]

 

lift a wheel and it won't help you.

He's right, I have one on my (RWD) van and it's a great piece of kit for the purpose intended, but a Quaife/ATB diff won't help unless both wheels have a little traction.

 

They're lovely to drive with though, you won't know it's there 90% of the time as it's silent, but when you want to fire it off a roundabout it'll do the business without any fuss. I see that the prices have shot up in the last two years though.

[maystro]

Obviously some of you guys haven't driven on some of the roads or lack of roads down under.   Anything that can give a bit of extra traction is a bonus in between the pot holes and bull dust and I'm not talking about that which is on this forum.  

[imack]

I don't think you'll be disappointed with the quaife diff. It won't be as effective as a plate diff if a driven wheels off the ground but it also won't have the down sides of a plate diff.
It's much better than an open diff on wet tarmac and in dry conditions pulls the front end in tighter through a corner under power just at the point you'd normally expect understeer with an open diff. They also seem to be very reliable.
Until you push the car you're not aware that it's fitted.
It can magnify torque steer issues if you've got excess wheel off sets, spacers, metro hub carriers etc.

[Cooperman]

I must admit I have never driven with a Quaife.
I do recall a conversation with a good friend of mine who was a British Rally Champion and we were discussing LSD fitted Minis.
He said that he had used one and on an RAC Rally it had cost him a lot of time. The different way they perform on gravel made the car slower.
For racing, sprints and hill climbs, however, they will enable better times.

[Spider]

Personally I have never been able to get to like LSD's on road cars. In fact, it might be me as I have tried them and they make me nervous when trying to go quickly.

For racing where the ability given by an LSD to get back on the power early in the corner is a big advantage they are great for saving a second or more per lap. Remember, unlike a normal diff, with an LSD, when you lift off the car tends to understeer, whilst when the power is applied it tends to 'turn-in'. This is the opposite of what I have always liked about the Mini - the 'lift-off oversteer'.

I do recall the first time I drove a Cooper 'S' with an LSD. It was at night on a twisty road in the wet. I got to a corner which tightened and I lifted off to find it went into what was to be terminal understeer. Then I realised that I needed to have the power applied and it just, only just, got round the corner.

However, some drivers (better than me!) do get good results with those diffs on tarmac rallies, although they are a bit of a liability on gravel where the lift-off oversteer is essential. I suppose a lot of it what you get used to over time.

They are really for competition and not any real advantage on public roads.

 

Peter, totally agree with you here on LSDs. I tried one in a road car years back and couldn't get the damn thing back out fast enough. Utterly dreadful thing. On the sealed track, it's a different matter, but does need some learning. The ATB behaves very differently.

 

 

Noted what many have said here re: ATB for the road and that's fair enough. Perhaps I might driver harder ? but there's no way on god's earth I'll ever go back to an open diff of any type in a Mini or a Moke. I always found 'fanging' on corners, it was very easy to have that inside front wheel light up. Off road, I was for ever spinning one wheel or the other (and I wasn't alone here), but since running an ATB, I'm yet to spin a wheel in these conditions. For me, they are everything I was looking for in an LSD but with no down side. And, unlike open diffs, these don't break.

[Maccmike8]

Not in a classic Mini but Ive had several quaife diffs and on the road they really do make for quick travelling.

[Ethel]

For anyone curious & not familiar, ATB stands for auto torque biasing.

 

The standard diff equalises torque by feeding the grip from tyres up the driveshafts to act on the bevel gears equally & opposite.

An ATB is full of helical gears instead that usually generate equal & opposite side loads that cancel one another out, similar to the open diff.

 

If one wheel loses grip, the torque imbalance will drive the gears on slipping side against friction surfaces (because of the helix generated side load) until the torque is equalised in the diff, but that's achieved because the wheel with most grip is equal to the wheel with least PLUS the torque reaction created internally by the friction surfaces. So, just like an open diff, if there no torque on one side there's no torque transmitted to the other side either because there's no  force to generate the side loads from the helical gears that make it work. 

 

It would enhance the function of traction control using the brakes though.

[maystro]

A question here for anyone that has used a Quaife diff. 

 

My normal open diff turns by hand when I turn the output shafts, the Quaife diff just seems locked.  Is this normal for a ATB diff?   I don't want to go to the trouble of installing this and then find it's screwed because some over zealous customs officer has tampered with it, because they did search the box.

 

Thanks Brad

[imack]

That's how they are, they do have a preloaded on them.

[maystro]

That's how they are, they do have a preloaded on them.

Thanks mate, that is all I needed to hear

[maystro]

That's how they are, they do have a preloaded on them.

Actually double bonus then so I won't need to add shims on the crown wheel  bearing side to shim the diff like a normal open diff?

 

Thanks  Brad

[GraemeC]

The diffs are preloaded internally - you will still need to follow the fitting procedure to preload the bearings (according to which type of bearing you have).

[nicklouse]

 

That's how they are, they do have a preloaded on them.

Actually double bonus then so I won't need to add shims on the crown wheel  bearing side to shim the diff like a normal open diff?

 

Thanks  Brad

 

That has nothing to do with the duff bearings. How to set up the diff bearings depends on which you are using.

[maystro]

Yeah thanks guys, I got ahead of myself and forgot this diff still relies on normal bearing principles.   

[MiNiKiN]

The diffs are preloaded internally - you will still need to follow the fitting procedure to preload the bearings (according to which type of bearing you have).

A bit of topic hijacking and cross-threading:
 I fitted a x-pin diff to my remote gearbox with hardy spicer outputs - during assembly for clearance check (MS RHP bearings and MS gasket set) I had 0.8mm (i.e. 31 thou) clearance.

As I only had shims for half that amount and the gaskets had 0.4mm thickness each, I decided to just use Dirko HT liquid sealant instead and add a 0.05mm (2 thou) shim on either side to provide the pre-load. 

The liquid sealant thickness will not be much mor than 1 thou if at all - any concerns or suggestions about my doing? Aprreciated.

M