 | Home > Technical > ATB (torsen) front and rear install |
 
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436   
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ATB winter driving update  Click image to enlarge With the season more or less behind us (just had 12 inch yesterday and another 5 expected today) thought it would be good to update on snow behavior of the ATB’s. First of all I am not driving as a madman on snow, it’s not the acceleration but the braking that puts you in expense. Forward traction is anyway not the problem with a defender compared to a 2 wheel drive, so it’s a bit of hairsplitting searching for differences in such driving conditions when you drive “responsible” anyway. Very simply put I had the TC only coming on when pushing it. That’s the conclusion of the season in one sentence. But it’s not that simple. In reality this means that you need to be on ice or hard packed snow and floor it before the TC will kick in. In ALL normal driving behavior the TC sleeps through it and the ATB’s absorb the wheel spin. What I describe below is on snowed roads, from fresh to hardpacked, not a watery slush where you’ve got contact with the tarmac underneath. During “sportive” driving you notice a bit of torque steer which you easily correct by steering, no need to go off the accelerator. During acceleration on real slippery stretches you’ll notice the front wheels searching for grip, a bit of left-right steering by itself. All very, very reassuring. Going over the limit and provoking things ends up in more torque steer and much longer controllable drifts. But that’s not really relevant, just fun. When pulling the horsebox it was interesting standing on slopes and then starting of again, the wheels search for traction for a moment and of you go. Again, if not pushing it no TC involved. (in this case when TC activated it killed power or stopped the tires from digging in long enough to get grip, so I would even recommend not to have TC on in such situations.) While driving traction was optimal at all times, especially noticeable when driving slowly in tight spots/small roads. One first remark though, and this is nothing different from an open diff situation but the effects are more pronounced; coasting vs “under drive”. As long as a bit of throttle is applied there is a very reassuring stance on the road, but going into coasting the extra grip the ATB’s give is lost and things become less stable. Put this in combination with going downhill and it can come as a surprise. Not a bad thing of the ATB’s just a noticeable difference 2nd remark goes together with it and surely if you don’t have ABS/TC. As long as you are braking with the clutch engaged everything is stable and straight. Once you depress the clutch pedal the road conditions and eventual brake force differences between the calipers come into play, big time! To explain; we have a single lane driveway to the company which was half flooded during a melt. Left side of lane pure ice covered with a fresh 2 inch layer of snow. Right side of lane tarmac with 2 inch of snow. Coming at the end of the lane at an optimistic 45mph I was braking straight ahead coming to a halt. The moment I depressed the clutch I got into a 180° spin as the left tires were blocking on the ice surface and the right tires still had some part of traction. (note that I had ABS/TC switched off) I was then doing something as 10mph, luckily. I redid the “test” multiple times with the same effect each and every time. Due to a broken ABS sensor I cannot check what the effect is with ABS/TC ON at this moment but I did not notice this as clearly before with ABS. (what seems logic) Offroad. We drove a bunch of vineyards (to give an idea of terrain) after a 3inch snowfall onto some week old snow. I was absolutely shocked by the results. BFG AT + fresh snow + ATB = no TC. Not once, not even going up the steepest inclines. A couple of days later I got bottomed out on some substantial snowdrifts while laning. No help there. The smaller drifts though gave a great demonstration of the ATB engaging and doing their job. Again, when not flooring it TC would not kick in. We drove the lane back, at 45mph smashing into the drifts, this had TC coming on multiple times when the car was forced sideways due to resistance of the snow on the higher side of the drift. Big fun and dangerously reassuring. To conclude and to come back to the start point. The ATB’s are a big help and make you very reassured of your driving. So much we were doing 45mph during a blizzard not seeing the edge of the road and ending up hood-high in a ditch. It was after a bend, going downhill. The only thing keeping us from a spin in “mudrut’ style (see light chase of this month) was that i did not pressed my clutch till the very last moment. A 40m slide-track, and dented ego were the only consequences till I fully hit the brakes at full throttle during the recovery and instantly blew a CV joint. So also ATB related, the brake assist is working but not the best idea at full power.
Admin note: this post has had its images recovered from a money grabbing photo hosting site and reinstated  |
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13th Feb 2013 2:16pm |
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| Morea Member Since: 20 Jan 2011 Location: Asturies Posts: 201 |
Hello. Finally my ATB debuts. They are wonderful. Mount both front and rear. I have only demomento this video from inside my Defender 110 TD4.
To say that the ground was heavy clay. he climbed slowly in second to see how the locks worked. I said great. I already put more videos. Thanks to Dave Ashcroft. &list=UU8KFxCjwX5BKaQFUefW9azg&index=2 http://www.clublandrovertt.org/index.php?a...ype=avatar |
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25th Feb 2013 8:09pm |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436
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Kim,
as this is a ATB diff, not a LSD diff the oil is of no importance or influence. Standard LR spec diff oil does the job. |
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4th Feb 2014 8:35am |
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| kimhas Member Since: 08 Feb 2013 Location: Norge Posts: 19  
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Thanks .
Is full syntetic tur best? Prise is not importent MY2011 Defender 110 |
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4th Feb 2014 10:29am |
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| kimhas Member Since: 08 Feb 2013 Location: Norge Posts: 19
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Click image to enlarge To day I put in the Ashcroft diff you recomended Tatra! MY2011 Defender 110 |
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8th Feb 2014 6:53pm |
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| geobloke Member Since: 06 Nov 2012 Location: Nottinghamshire Posts: 4410 
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Almost 2 years to the day you posted this thread Tatra. What are your opinions of the Ashcroft ATB now? Still enjoying them?!?
Anyone else? |
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18th Jun 2014 10:04am |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436
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Hi,
In short they perform flawless. 
It is not till driving a non atb'ed defender you notice how big the difference really is. I do need to point out something however When people want to compare they tend to send you into a non possible situation eg deep endless mud , extreme ondulations and the steepest hills possible where the limiting factor is not drive to the wheels but traction, gravity or ground clearance. This masks the benefit of the diffs. It is in call it medium and normal driving the atb's are shining. I have first hand experience in the last months (due to a private experience center we have opened over here) with TC'ed and non TC'ed defenders (90-110 and 130) and my 110 with the atb's in all possible weather conditions. I am always shocked how the other cars need to be worked or work (tc kicking in all the time) where mine is walking through without drama. I would not go back. To illustrate it in another way the owner of The Estate ordered a set of ATB's the same day he took delivery of his new 130 (without TC) He felt as if he bought half a 4x4 after driving my 110. It is only a matter of time when we will also install them in the other 3 defenders he runs on his grounds as these need simex tires during the wet season to get to/through the vineyards and this results in broken halfshafts every year due to the intelligent driving style of the resp drivers. (hills + rocks + clay) When taking customers around our tracks i every time get the remark "you have lockers installed don't you?" when i then say it are ATB's most of the time i get blank looks but i know of one owner of a 90 which took out his ARB's and had the atb's installed instead. 
I once made an experiment on a 400m long steep track. the tracks were wet and are on mulched grass on clay ground. During this climb (initial acceleration and then maintaining speed, TC switched off) i traced back 27 spots where 2 wheels where having traction at the same time (visible in the markings on the tracks) So just on this 400 meter the ATB's prevented wheelspin or TC interfering 27 times. (driving time around 1minute) Hope this gives an impression on how satisfied i am and how usefull the ATB's are.  |
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18th Jun 2014 12:32pm |
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| mikeh501 Member Since: 07 Jan 2013 Location: United Kingdom Posts: 1142
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sounds great.
my ATB is due to be fitted into the rear of my 90 next week Your write up was one of the deciding factors!
If it works out, ill also put one in the front. If I dont get the behaviours im looking for ill move the ATB into the front and put an ashcroft full locker in the rear |
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18th Jun 2014 1:03pm |
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| Lodelaner Member Since: 04 Feb 2010 Location: Lambourn Posts: 631 
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Having had them front and rear in a 90 I would fit another to the back - but never again to the front. The power-on understeer and lift off tucking-in effect was too much for me. The steering wheel unwinding/self centering was fine though.
I had a horrible moment on a wet roundabout where the car ploughed straight on - I think there was a diesel spill - but it was an unpleasant experience. I would imagine the effects would be less pronounced in a 110, but can't say as I haven't experienced it myself. JB @Lodelaner Instagram Youtube greenlaning and other LR related content |
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18th Jun 2014 1:26pm |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436
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Widget may i ask if this was this exact ATB (not eg a detroit locker)?
The reason for asking is that i absolutely do not have "unwanted" ( )side effects when driving normally.
I can floor the 110 on a roundabout and just induce a 4wheel drift but all very controlable and even abruptly lifting the accelerator does not cause anything out of control. On wet roads you can feel the front searching for grip (MT tires) when provoking but again absolutely nothing out of control and to my opinion much more controlled than without the ATB's. Have to add behavior was similar with my previous disco 1 with a tuned 4l V8, 2 inch lift and truetracs. I understand on a 90 the influence might be worse. |
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18th Jun 2014 1:38pm |
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| landy andy Member Since: 15 Feb 2009 Location: Ware, Herts Posts: 5668 
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I was running a KAM LSD in the front, and a kaiser (like a Detroit) in the rear of my 90 without TC. They were great off road but the kaiser was horrible on the road as would bang and give loads of play in the drive system. I've now sold my 90 but kept my KAM diff and plan to install in the front then an ATB in the rear of the new 110 with TC, and also change suspension for extra articulation. Can't wait, but must for the warranty.
Andy |
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18th Jun 2014 5:52pm |
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| Morea Member Since: 20 Jan 2011 Location: Asturies Posts: 201 |
I also took ATB's. Delighted with them.
[img]https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xfp1/v/t34.0-12/p720x720/1081707_10202495375497621_934495605_n.jpg?oh=479ea1833b0443cea5d000117096869d&oe=53A40104&__gda__=1403260385_b238d0a7e7ed6aa523bb1604fd4021f2[/img] [img]https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpf1/v/t34.0-12/p720x720/1781389_10202495373817579_85177957_n.jpg?oh=39f6e72bfa19f8505039a4604d91cfee&oe=53A3A240&__gda__=1403253311_e6bef97261fba8de506b5c75e68afed7[/img] [img]https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpa1/v/t34.0-12/1624441_10202495370017484_795091371_n.jpg?oh=d4c6b21a238d5087c7b1b85e919abc66&oe=53A3AC06&__gda__=1403238246_078ab464f124a7801b6ff3e65b98782d[/img] [img]https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpa1/v/t34.0-12/1616667_10202495368537447_1600641321_n.jpg?oh=e537992398217a0b517a790014d7dd1d&oe=53A40AEC&__gda__=1403228989_adcaaa7d3cd13f0a8f9f046dd91c6af8[/img] Sometimes pictures are worth a thousand words.  http://www.clublandrovertt.org/index.php?a...ype=avatar |
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18th Jun 2014 5:52pm |
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| Lodelaner Member Since: 04 Feb 2010 Location: Lambourn Posts: 631
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Yup an ATB in the front. It was fitted in a 50th - so the additional power and short wheelbase may have exacerbated the effect. It was on BFG Mts. JB @Lodelaner Instagram Youtube greenlaning and other LR related content |
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18th Jun 2014 8:17pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17353 
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I have Ashcroft ATBs front and rear in my Puma 110 (on 285 BFG KMIIs) and have never experienced any peculiar handling resulting from them. I find them brilliant and have no hesitation recommending them.
Ashcroft Transmissions seem to have been out of stock of these for a very long time though. Had anyone heard anything from them about when they're likely to be available again? |
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18th Jun 2014 10:14pm |
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