Geared LSDs are less prone to wear than the clutch type, but both output shafts have to be loaded to keep the proper torque distribution characteristics. Once an output shaft becomes free (e.g. one driven wheel lifts off the ground; or a summer tyre comes over ice while another is on dry tarmac when the car goes uphill), no torque is transmitted to the second shaft and the torque-sensitive diff behaves like an open diff.

In my opinion, if you want something to do a job, and are willing to pay £450 for it, you want it to do the best job it can, not wimp out halfway through.

So, let's get this right, as long as the two wheels are on the ground then torque will be biased automatically BUT if you lift a front wheel then the ATB reduces torque to the other wheel bringing the free wheel back down to ground so it can lay down power again

Edited 26 April, 200719 yr by LregG

Geared LSDs are less prone to wear than the clutch type, but both output shafts have to be loaded to keep the proper torque distribution characteristics. Once an output shaft becomes free (e.g. one driven wheel lifts off the ground; or a summer tyre comes over ice while another is on dry tarmac when the car goes uphill), no torque is transmitted to the second shaft and the torque-sensitive diff behaves like an open diff.

In my opinion, if you want something to do a job, and are willing to pay £450 for it, you want it to do the best job it can, not wimp out halfway through.

So, let's get this right, as long as the two wheels are on the ground then torque will be biased automatically BUT if you lift a front wheel then the ATB reduces torque to the other wheel bringing the free wheel back down to ground so it can lay down power again

Not quite, on the ATB (geared diffs) are basically an LSD up to a certain point.... and then when you do lose traction, they act like an open diff- i.e the wheel which broke traction first, will then get the most torque, thus spinning more, not really a characteristic i'd want from an lsd.

Geared LSDs are less prone to wear than the clutch type, but both output shafts have to be loaded to keep the proper torque distribution characteristics. Once an output shaft becomes free (e.g. one driven wheel lifts off the ground; or a summer tyre comes over ice while another is on dry tarmac when the car goes uphill), no torque is transmitted to the second shaft and the torque-sensitive diff behaves like an open diff.

In my opinion, if you want something to do a job, and are willing to pay £450 for it, you want it to do the best job it can, not wimp out halfway through.

So, let's get this right, as long as the two wheels are on the ground then torque will be biased automatically BUT if you lift a front wheel then the ATB reduces torque to the other wheel bringing the free wheel back down to ground so it can lay down power again

Not quite, on the ATB (geared diffs) are basically an LSD up to a certain point.... and then when you do lose traction, they act like an open diff- i.e the wheel which broke traction first, will then get the most torque, thus spinning more, not really a characteristic i'd want from an lsd.

I don't think that quote is saying that yoof, it's saying that if there is absolutely no load on the diff on one side (i.e. the wheel is off the road or spinning on ice) then it will not automtically adjust the bias and therefore act like an open diff.

If, however, you spin a wheel while pulling away the diff still sees resistance and adjusts torque to the none spining wheel therefore acting in the same way as an LSD.

Edited 26 April, 200719 yr by LregG

Geared LSDs are less prone to wear than the clutch type, but both output shafts have to be loaded to keep the proper torque distribution characteristics. Once an output shaft becomes free (e.g. one driven wheel lifts off the ground; or a summer tyre comes over ice while another is on dry tarmac when the car goes uphill), no torque is transmitted to the second shaft and the torque-sensitive diff behaves like an open diff.

In my opinion, if you want something to do a job, and are willing to pay £450 for it, you want it to do the best job it can, not wimp out halfway through.

So, let's get this right, as long as the two wheels are on the ground then torque will be biased automatically BUT if you lift a front wheel then the ATB reduces torque to the other wheel bringing the free wheel back down to ground so it can lay down power again

Not quite, on the ATB (geared diffs) are basically an LSD up to a certain point.... and then when you do lose traction, they act like an open diff- i.e the wheel which broke traction first, will then get the most torque, thus spinning more, not really a characteristic i'd want from an lsd.

I don't think that quote is saying that yoof, it's saying that if there is absolutely no load on the diff on one side (i.e. the wheel is off the road or spinning on ice) then it will not automtically adjust the bias and therefore act like an open diff.

If, however, you spin a wheel while pulling away the diff still sees resistance and adjusts torque to the none spining wheel therefore acting in the same way as an LSD. How could quaife get away with trading standards saying that it was a limited slip diff when it was not???

You mis-understand gregg. It is a limited slip diff, its just a limited, limited slip diff.

No load means no load, be it wheel spinning on tarmac, or ice, same differance, trust me they will spin up like an open diff past a certain point. This is partly so it doesn't pull you all over the road like a proper diff.

From quaifes site

The Quaife Automatic Torque Biasing Differential enables your car to accelerate quicker and corner faster. How?

Simply by getting the power to the ground!

The Quaife differential powers both drive wheels under nearly all conditions, instead of just one.

With an normal open differential, fitted as standard on most cars, much precious power is wasted through wheel spin under acceleration. This happens because the open differential shifts power to the wheel with less grip - along the path of least resistance.

The Quaife differential, however, does just the opposite. It senses which wheel has the better grip, and automatically biases the power to that wheel. It does this smoothly and constantly, and without ever completely removing power from the other wheel.

In cornering, while accelerating out of a turn, the QUAIFE biases greater power to the outside wheel, reducing inside-wheel spin. This allows the driver to begin accelerating earlier, exiting the corner at a higher speed.

The Quaife differential also controls loss of traction when the drive wheels are on slippery surfaces such as ice and snow or mud, providing the appropriate biased traction needed to overcome these adverse conditions. The Quaife ATB differential provides constant and infinitely variable drive. Power is transferred automatically without the use of normal friction pads or plates seen in other limited-slip designs.

A spinning wheel still has load, if a tyre is smoking it is because of friction/heat therefore there is a load, the diff senses this and shifts torque to the other wheel. That is my understanding of it. If you took off one driveshaft and tried to drive it then no, it would not drive due to the fact that you do not have two different loads on either side of the diff, this is where a LSD would supply drive due to the fact that it actually locks up

Edited 26 April, 200719 yr by LregG

Click Me Gregg

Read it through. Like i said, once a wheel starts to spin freely (no load) then it will act like an open diff.

Shall we go round in circles again?

No need to go round in circles mate

Geared LSDs are dependent on the torque and not on the speed difference between the output shafts. Such differentials may be acceptable on dry pavement

So, on a dry road wheel spin will be avoided just as well (or as close as) a LSD that locks due to the fact it will distribute torque to the wheel that shows that it has the most grip

The main difference between the two is a LSD A) locks and b) is shaft speed sensing and gear type diffs are A) Torque sensing and B) never fully lock which means they reduce torque steer and will not be snatchy in car parks etc

Edited 26 April, 200719 yr by LregG

NO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Only to a certain level, as soon as you break traction seriously on one wheel, it will behave like an open diff.

This is what i'm trying to say, they're fine for heavier than normal launches. But if you acutally want to get somewhere, or round a sharp corner, you're better investing in a pair of slicks and some driving tuition.

Or just going back to school.

NO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Only to a certain level, as soon as you break traction seriously on one wheel, it will behave like an open diff.

This is what i'm trying to say, they're fine for heavier than normal launches. But if you acutally want to get somewhere, or round a sharp corner, you're better investing in a pair of slicks and some driving tuition.

Or just going back to school.

Have you driven a car with an ATB in yoof??

Edited 26 April, 200719 yr by LregG

well, my thoughts seemed to be right, i think i held my point til 'the cavalry' arrived LOL

i null voted but cound me definately for a plate.

Actually yes, but only in a car park, and i've driven a couple of cars with clutch type diffs.

Make your own decision, i really don't give a fuck, but whilst your wheelspinning off the line at santa pod, i'll be past the 60ft marker

That all depends if i'm in the gripper equipped eaton or the ATB equipped beige beast eh?? LOL

F A C T

Either or, feel lucky against the mk1

F A C T

act on it

That's you're car isn't it gregg?

Either or, feel lucky against the mk1

yeah, why not, it would be good to see two polo's run under 14 secs at the same time

That's you're car isn't it gregg?

No mate, hugely mistaken, mine, as my login name suggests, is an L reg which looks a lot like the car in my sig

F A C T

that owned the thread..

that owned the thread..

euro-owned

that owned the thread..

euro-owned

wtf?

Made this into a seperate topic

so the other one can be used to gain \/iews on what people want

Although debating the pros and cons between the different LSD solutions kind of does affect the choice people will make on the Poll.

Constructive ATB vs plate comparison:

Borque biaising/ATB (ie Quaife/Peloquin)

- maintenance free (fit & forget)

- proven design

- negligible effect on steering effort

- smooth progressive diff lock up

- if one wheel loses grip, the diff will unwind and not lock up. An ATB requires an element of grip from both wheels to operate. It can regain grip, and whilst losing grip the car remains totally driveable.

- inferior to a plate diff on any cornering which could give rise to the inside front wheel lifting from the ground (but if your inside wheel lifts, your suspension arguably is not set up to maxmise grip from the car)

- if a driveshaft snaps, the car behaves like an open diff, ie you cannot drive on one driveshaft

- little if any difference to a plate diff on quarter miles, since both lock and there are no cornering influences to cause the picking up of inside wheels

Plate (ie Gripper, Gemini)

- found in race paddocks and rally stages, wherever clocks are ticking and wherever the last 10th of a second counts

- results in heavy steering on non-PAS equipped cars

- snatchy, depending on preloads and ramp angles

- allows kerb hopping eg where those 10ths really matter:

http://www.vwmotorsport.com/downloads/Imag...carvell_02x.jpg

http://www.vwmotorsport.com/downloads/Imag..._Carvell02x.jpg

- requires maintenance: if you use one in a road car, you can expect to need to replace diff plates periodically (gearbox strip £200-£300 + plates)

- allows competitors to drive out of stages on one driveshaft, but at reduced pace, and often overheating the diff plates depending on distance. Cue diff rebuild, costs as above.

- traditionally cost more than an ATB diff, though in this instance, Gripper Group Buy prices appear to be similar

So in conclusion:

- for circuit-based competition where regulations allow, in my mind there is no question about what you should buy, subject to cost: a plate diff. You're there to compete, that's all that matters.

- for a fast road car, where replacing diff plates is not a desirable option, and for quarter miles, choose an maintenance free ATB. They're smoother to drive, it keeps the road car civilised, and steering/parking acceptable.

- for a trackday car, it is a closer call, but I would still recommend an ATB, even for quarter miles, simply because the last 10th of a second does not matter. If you're determined to experience a plate diff, I wouldn't deter you, and depending on your route to circuits, you may be able to put up with adding this uncivilised aspect to a car. If you're trailering to trackdays, it just boils down to personal choice.

Unless you have a team of mechanics or a 4-post ramp access, the reality is that whilst:

- having the option to adjust pre-load on plate diffs

- or having differing availability of ramp angles (£££)

...may be an option, it is unlikely ever to be taken advantage of. When did anyone take a gearbox out for fun?

Cheers,

Chris

Thanks Chris.

Just to further the original argument: Do you know what happens when one wheel looses traction as opposed to losing contact completely in an ATB differential?

From my understanding, there is some kind of ratio that is set into an ATB diff, whereby if one wheel is providing resistance that equates to less than this ratio of the total resistance, the diff acts as if it's open. If this is the case, can you get more aggressive ATB's that will still try and "lock" up when one wheel is spinning with contact?