BogMonster Posted October 5, 2009 Share Posted October 5, 2009 Just browsing around the selection of Christmas presents on Ashcrofts website and I see they now sell Quaife diffs. You don't seem to hear a lot about these on here despite them being a well known name - anybody on here use them for general off road use? Just curious really, not really that likely to buy one (would like to just got better things to spend a grand on for the occasional benefits that or ARBs would bring me) Any thoughts? I realise they are not as good as full locking diffs but as a "fit and forget" solution I should think they make a fair difference? I always thought they would be really good in a vehicle with ETC. Discuss Quote Link to comment Share on other sites More sharing options...
Lara Posted October 6, 2009 Share Posted October 6, 2009 Hi BM, I use them in my 90, Fitted them years ago and never a problem, used in conjunction with the TC as you say give me perfect control, (except for driver input ) and as you say, "fit and forget" they have never made me regret fitting them, always give me great traction and I never forget to turn them on! However on occasions when the TC sensor gets knocked out of range or a wire broken, then you do need to modulate the brake pedal if you lift a wheel or if you are in very goopy slop. Otherwise they are perfect. However I would use ARBs for a challenge only vehicle! Lara Quote Link to comment Share on other sites More sharing options...
SteveG Posted October 6, 2009 Share Posted October 6, 2009 Lara - I've always wondered if the LSD will cause it to fishtail a lot when in wet grass or slippery mud without ruts? I've a couple of road cars with rear LSD's and it was easy with the right pedal to get them fish tailing a lot in the wet. Cheers Steve Quote Link to comment Share on other sites More sharing options...
BogMonster Posted October 6, 2009 Author Share Posted October 6, 2009 How does the strength compare to the other options? Detroits seem to have a reputation for going bang a bit (not just when cornering...) and ARBs seem pretty well bombproof. Going on the price the Quaife should be pretty good? Quote Link to comment Share on other sites More sharing options...
Lara Posted October 6, 2009 Share Posted October 6, 2009 Fitted mine in 2003 and never had a problem, Done countless halfshafts, 2 ring and pinions, 3 props, but never touched the Diff, So touch wood, Very strong! I think one of the good points of the Torsen system is it's ability to be gentle when not needed, Ie on grass etc where you need gentle control and not locked axles. It will fishtail under power but not if you are gentle! Lara Quote Link to comment Share on other sites More sharing options...
Dave W Posted October 6, 2009 Share Posted October 6, 2009 For off road purposes I found the Quaife diffs gave marginal, if any, advantage over open diffs other than being relatively indestructable. The problem with them is that they are designed to distribute power when both wheels have traction, in terms of directing power to the wheel with most grip they only work within a very small band and as soon as the difference between the two wheels exceeds that band it acts like an open diff with all the power going to the wheel with least/no traction. I used them for both trials and challenges and struggled to find any situation where they gave better performance than an open diff. Not sure about benefits when used with TC though as I've not tried that but I wouldn't expect any great improvement. I spoke to Quaife at length about my disappointment with the diffs for off road use and I sent the diffs back to them a couple of times to make sure they were within spec before getting one of their engineering types on the phone. He said that the problems I was experiencing (no difference between Quaife and an open diff off road) was to be expected because the diff simply isn't designed for off road use and they would never recommend their diffs for that purpose. The diff needs resistance from both wheels to work and as soon as one wheel loses traction all the power will be sent to that wheel. Quote Link to comment Share on other sites More sharing options...
Exmoor Beast Posted October 6, 2009 Share Posted October 6, 2009 ...apparently its a Quaife diff in the rear salisbury axle of my 110. I've never had any cause to take a good look because it just works and never breaks famous last words eh! It seems to find traction where others struggle offroad, especially when combined with a touch of left foot braking if its really slippy I've found. As others have said it will spin a single wheel with no resistance, I've propped the axle on a log to test it, I can't really explain it but you can feel it trying to 'engage' as the revs rise. If you blip the throttle it will just drive off the log so power is getting across the axle somehow. Likewise at low revs just dabbing the brakes will make it drive off the log. Quaife seem to be std fit on wildcats so that should say something about their durability as does the fact I haven't broken it Will Quote Link to comment Share on other sites More sharing options...
Exmoor Beast Posted October 6, 2009 Share Posted October 6, 2009 ...oh and its a right handfull in the snow if you aren't very gentle Will Quote Link to comment Share on other sites More sharing options...
Lara Posted October 6, 2009 Share Posted October 6, 2009 That is exactly the trick with them, TC or left foot braking, just a tiny bit makes a massive difference! and you find that the bigger the wheels / tyres you have the less you need to brake as the large mass of the big tyres will give enough resistance to make the Torsen system come into play. You do need to get used to getting the best out of them. Lara Quote Link to comment Share on other sites More sharing options...
RangeyRover Posted October 6, 2009 Share Posted October 6, 2009 Just browsing around the selection of Christmas presents on Ashcrofts website and I see they now sell Quaife diffs. You don't seem to hear a lot about these on here despite them being a well known name - anybody on here use them for general off road use? Just curious really, not really that likely to buy one (would like to just got better things to spend a grand on for the occasional benefits that or ARBs would bring me) Any thoughts? I realise they are not as good as full locking diffs but as a "fit and forget" solution I should think they make a fair difference? I always thought they would be really good in a vehicle with ETC. Discuss (devils advocate) I really really like the idea, but isnt the quaife the same as a truetrac but twice as much? (/devils advocate) Milner truetrac prices and I know steve at crown diffs really rates the Truetrac, I had a long chat with him about buying some, when I asked how many returns he had seen from them. The answer was one. total. crown diffs truetrac Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted October 6, 2009 Share Posted October 6, 2009 Quaiffe are used in the racing scene a fair bit here, LSD offers some assistance, but can also make for odd moments too strong, well built, shafts are £££s often LSDs need setting with preloads different for front to rear HTH Nige Quote Link to comment Share on other sites More sharing options...
ashtrans Posted October 6, 2009 Share Posted October 6, 2009 Hi, these diffs use an unsupported helical gear arrangement, each gear set sitting in a 'pocket' in the diff center, the gears being in line with the axle axis. When one wheel has a 'good' grip eg on blacktop, but the other wheel has less grip eg on grass, there is a tendancy for the wheel with less grip to spin. In order to spin a wheel the gear set's in the diff are forced to turn, as they are 'designed' to be inefficient torque will be transmitted to the wheel with grip. The number of gears, shape of the pocket and the helix angle of the gears, all contribute to their 'efficiency'. As one wheel begins to slip it will transmit torque to the other wheel depending on how much slip is taking place. This is the 'progressive torque bias' . All Quaife diffs come with a preset loading or pre set bias on the helical gears to accomodate the situation where there is insufficient grip ( eg axle twist) on one wheel to start the bias loading to take place, if there was no pre set bias then with one wheel in the air there could be no bias to the other wheel. On road cornering the handling is almost 'transparent' as the outer wheel drives faster than the diff and tries to lock it the inner wheel drives slower than the diff and unlockes it so there is no cross bias effect. These diffs are ideal for fast competition eg rally raid driving where most of the time both wheel have some drive contact and used in this situation can achieve almost equal power distribution. Not as good in a 'trials' situation where one wheel is often 'free' ie off the ground as it sometime needs left foot braking to load the 'free' wheel to allow it to 'torque bias' across to the other wheel. Whilst the Truetrac and the Quaife work on a the same principle, they are far from the same, differences are the quaife has 6 spiral gears whereas the Truetrac has 3, also the quaife materials and build quality is far better. The Truetrac is still OK for the greenlaner etc but the quaife is on a motorsport level. Quote Link to comment Share on other sites More sharing options...
Mark90 Posted October 6, 2009 Share Posted October 6, 2009 I've always wondered if the LSD will cause it to fishtail a lot when in wet grass or slippery mud without ruts? I've a couple of road cars with rear LSD's and it was easy with the right pedal to get them fish tailing a lot in the wet. The comp safari car I co-drive in has a quaife LSD in the back, and yes it does help get the back end out, which suits my drivers prefered cornering style, but it's not really suseptible to excesive fishtailing. Though you do have to be careful on side slopes, gentle throttle application or you'll soon be facing up hill. Quote Link to comment Share on other sites More sharing options...
SteveG Posted October 6, 2009 Share Posted October 6, 2009 I think one of the good points of the Torsen system is it's ability to be gentle when not needed, Ie on grass etc where you need gentle control and not locked axles. It will fishtail under power but not if you are gentle! Lara Thanks for the explanation Lara. And to Dave Ashcroft for his comprehensive response too. Cheers Steve Quote Link to comment Share on other sites More sharing options...
BogMonster Posted October 6, 2009 Author Share Posted October 6, 2009 Interesting stuff, thanks Quote Link to comment Share on other sites More sharing options...
SteveG Posted October 7, 2009 Share Posted October 7, 2009 but it's not really suseptible to excesive fishtailing. Must have been the 400bhp and my ham fisted driving style Cheers Mark, I missed your reply earlier Quote Link to comment Share on other sites More sharing options...
Mark90 Posted October 7, 2009 Share Posted October 7, 2009 Ah that's where we're going wrong we obviously need more power Quote Link to comment Share on other sites More sharing options...
ashtrans Posted October 8, 2009 Share Posted October 8, 2009 Hi, we are aware of the limitations of the Quaife/Truetrac and have been looking at 'other' solutions for a LSD to suit the driving conditions where a Quaife is not acceptable, cross axle etc. We have been working on an alternative and have produced the 'Rover' version of a Traction Master, those who came to see us at Billing would have seen the prototypes. The 'Traction Master' is a plate type LSD but with unique design features, it has a split center design housed within a 'conventional' case, the split halves each have 4 trapezoidal pockets acting on the cross pins. (many conventional LSD use the planet gears to generate side thrust which imposes severe design constraints) With the split center design the torque applied to each wheel is a function of the power applied, the number of plates and the angle of the pockets. The Traction master diff relies on the input power to the diff causing the cross pins to act on and separate the split halves to create torque across the diff, it does not rely on friction created within gearsets to limit the slip. As the torque applied to the diff creates clamping action the friction on the plates slip is limited from the start of a cross axle. More to follow after testing has been completed. One final comment on the Quaife, they offer a 'limited' lifetime warranty, in my opinion this alone makes the extra cost over the Truetrac worthwhile. Ian Ashcroft Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted October 10, 2009 Share Posted October 10, 2009 Thanks Ian, some really interesting reading here. I've got a Trutrac in the back of my Ninety and I find it goes further than it did with two open diffs, particularly if helped with a little left foot braking or using the inertia of the tyre as a 'load' across the diff. It's not an ARB and never will be, but it's simple and I like getting my head around the load paths of the helical gears etc. I find with moderate power (Tdi...) it helps cornering on loose surfaces - as the car leans and the inner wheel goes light, the power now comes from the outside rear wheel, turning the car into the bend. I'm sure V8 power means oversteer but it works well in combination. As Mark90 says, conversely that means you're sometimes left pointing uphill if negotiating a sideslope. Ian's comments re durability are interesting (and much appreciated), but I've not broken mine yet so it'll stay... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.