Traction control systems.

[George Collings]

I have no experince of how effective traction control systems are where the ABS system senses and brakes a spinning wheel so the differential sends more torque to the wheel with grip.

 

I watched a RWD Transit with it having on soft problems and wonder how people are finding them.

 

Mechanical limited slip differentials certainly work but I wonder how good the type that brake wheels are.

 

To stick or not to stick that is the question.

[colin]

We had to tow out a Morvano with tc, but I don't think a mechanical dif lock would have helped him once both wheels where spinning, 3.5t of van vs wet clay there's only ever going to be one winner.

[spospe]

George

 

I have a Transit with "Traction Assist", it is a 2008 model with rear wheel drive and the 140 bhp engine.

 

I have seen it operate on a few occasions when running on slippery surfaces and / or very steep roads with very sharp bends.

 

According to the driver's handbook it will only operate at speeds below 25 mph.

 

It helps, but it does not turn the Transit into a 4 x 4 device and fitting knobbly tyres would help even more (actually, knobbly tyres and Traction Assist would probably be a good combination).

 

Michael

[davenewellhome]

Jacqui has traction assist of this type on the Focus and in the recent snowy condition it helped a great deal. When it kicks in a little wheel spin symbol lights up on the dash and you can feel the steering snatch slightly. Near to us there is a traffic light controlled junction that is on a hill and when its wet it can be difficult to pull away uphill without some wheel spin, we also get the warning light flashing here and the slight snatching of the steering. Ours isn't switchable it seems so I can't do a comparison test of with and without.

 

D.

[Peter Highe]

My Mercedes Sprinter has a switchable version (it is normally on but you can switch it off) and is supposedly good for wet grass and so on but with RWD and four boots at the back I don't anticipate too many problems. Fortunately I missed all the UK snow so haven't yet tested it out fully.

 

Peter

[Den]

At the Stratford show to enter the lower field by the Hymer club tent, people were told to drive at speed across the badly churned up ground. Not one to drive across bumpy ground quick. I drove slow and felt the traction control engage on our Merc 3ltr auto. I thought it was to slow so stepped on the gas!!!!!!! nothing computers had taken over and what an amazing job they did. All the other vans around had mud up the sides. We had none. Should any one ask for a score 10/10..........

[Ranger]

I have a L.S.D. back axle on my old Transit. Works very well on wet grass and muddy fields, also handy in narrow country lanes when one needs to run the near side wheels on the grass verge. The wheel on the hard stuff still has some drive. L.S.D. Limited Slip Differential.

[Derek Uzzell]

George

 

I have Ford's Brake Traction Control System (BTCS) on my FWD Transit-based Hobby.

 

As Michael said earlier BTCS only functions below 25mph. Its default mode is ON, though Ford recommends that it be disabled for driving with snow-chains or when 'rocking' out of snow. As I avoid slippery surfaces like the plague, I can't say I've ever had occasion to test BTCS's effectiveness.

 

I understand that, unlike an LSD, BTCS (and similar systems that exploit ABS) does not operate when the vehicle is being reversed and this could be a disadvantage with a motorhome. On the other hand, while a permanently-engaged LSD that is sufficiently stiff to really improve traction on poor surfaces (mud, sand, wet grass, etc.) should be fine on a RWD motorhome, I'd be wary of its effect on the steering of a FWD one.

[olley]

Hi unless things have changed in the last 20 years or so LSD's and traction controls work entirely differently.

 

LSD is a mechanical lock up built inside the diff, .

 

Traction control uses electronic sensors to detect differences in wheel speeds and applies the brake to the wheel that's spinning the fastest.

 

Olley

[George Collings]

Thanks for all the responses.

 

I have never heard of any comparitive trials although I doubt if any maker offers a choice of types on the same vehicle to allow a clear verdict.

 

Olley mentions locking diffs that are used on extreme off road vehicles but these should not be confused with switchable Limited Slip Diffs that can be set to bias torque between wheels.

 

In 8 years with my FWD VW T4 I never got stuck but its happened twice in three years with my curent VW lt (Cut price Sprinter with VW engine and no ABS ) So I started looking for a LSD but there is nothing available because TCS is for both Spinter and LT.

 

Even 100 litres of water over the rear axle does not do the trick. The folding trenching spade worked though

 

Tractors and trials cars used to have independent brakes for each driven wheel but you need to see the wheels spinning to know which one to use and It would probably give an MOT inspector kittens.

 

We could do with a dry spell.

 

 

 

 

[Clive]

Hi george,

Our old Sprinter had it and its qualities were demonstrated well at the York show a couple of years back. We proceded with 2 axle trailer where other FWD vehicles without came to a halt. (IGNORING THE MARSHALS WHO WANTED ME TO STOP ALSO HELPED!)

 

Blinking caps lock!

 

Currently using wifi from No1 sons domain as we are without internet untill the week end.

Regards

Clive

 

[Brian Kirby]

Having tried Fiat's version of traction control up a snowy slope a couple of years back, it was not a success.  Braking a wheel, while reducing engine power, while wanting to go uphill, got the result you might expect, and we ended up with a tow! 

Peter Rosenthal's answer to a similar question in the MMM March "Interchange" (p189) goes into some detail on limited slip diffs.  He mentions Quaife Engineering,  ttp://tinyurl.com/am74da who make LSDs designed for FWD vehicles, and which replace the originally supplied diffs.  They do these for a wide range of vehicles, including most commercials.  Mk 7 Transit about £550 + VAT, supply only.  Don't know how difficult, or expensive, fitting would be - but I just may find out!

My guess is that two driven wheels are better than a set of knobbly tyres and, given the need to match tyres, including spare, are more likely to be useful in a wider range of circumstances for not a lot more cost.  You also get to wear out your regular tyres first!

[George Collings]

I tried Quaife first, they cover the earlier Mercs but not the Sprinter presumably because TCS was available from its launch.

 

Their latest unit can cope with very high power, it uses clever gearing and standard transmission oil and they warrant it for life for even for competion use. Phew

 

I have long believed that the percentage fo weight on the driven wheels is the critical factor for traction. Twin rear wheels allow heavier axle loading and the extra sidewalls give added purchase in mud.

 

I have the rear axle load but single wheels and they are not very good in slimy conditions.

 

Ps Its still raining.

 

[Ranger]

You are quite right Olley, nothing much has changed in the last 20 years. My car has some modern super system which is constantly ballancing the drive but I think it will cost me a fortune if it ever goes wrong. It is a Colt CZ2 built by Merc: in Holland.