wheel spin

UK PROFESSIONAL DRIVERS FORUMS THE UK PROFESSIONAL DRIVERS FORUM (INTERACTIVE)
1

Recently i have been working out of a semi rural location. As its autumn the leaves are falling and making the roads very slippery. The truck i drive (merc actros gigspace thing) has a mid lift axel on the unit thats not driven. Come to a hill with leaves on the ground and the wheels start spining (sounds/feels like they are spining long before the traction control lights up)

i have tried having the lift axel up and pressing the weight transfer button but doesnt seem to make much difference. I have also tried keeping it in as high a gear as possible to keep the revs down

any other tips i can try

2

Try to keep the weight of the load as far forward as legally possible.
Use lift and wt/transfer as you have been.

But if

cooper1203:
the roads very slippery.

little else to be done.

3

Franglais:
Try to keep the weight of the load as far forward as legally possible.
Use lift and wt/transfer as you have been.

This ^^^ . Unfortunately it’s the nature of the beast nowadays where operators place longevity over grip, hence todays commercial tyres tend to be made from the same compound as the tyres on a childs Dinky toy.

4

the maoster:

Franglais:
Try to keep the weight of the load as far forward as legally possible.
Use lift and wt/transfer as you have been.

This ^^^ . Unfortunately it’s the nature of the beast nowadays where operators place longevity over grip, hence todays commercial tyres tend to be made from the same compound as the tyres on a childs Dinky toy.

Are you serious■■? all this electronic cluster of crap to get the emitions down that almost makes the vehicle undrivable with any mechanical sympathy but screw the fact that its costing 1000’s in tyres and other bits adding to the ploution of manufacture and transportation. Sounds like a plan sam

5

pretty sure theres been countless fatalities from faulty tyres and indeed the rubber itself is soft as poopie now thats all got its origins in Chinese manufacture. Not that long ago i had a valve split ,this was unheard of back in the day.Someone i know had an almost new tyre let go on them pound to a pinch theyre cutting corners over in Asia

6

At what speeds do you get wheelspin? I find that I can re-engage cruise control below 10 mph. In fact you can come to a complete stop and pull away again with it still engaged and cc doesn’t produce much wheelspin. (I also never lower my midlift).

You can’t use both at the same time, midlift raised and weight transfer. If the midlift is raised which magic place is the weight being transferred from ? I don’t know if the weight transfer would actually lower the midlift if it was raised?

7

Read the book on how to work the midlift, on the Volvo I drive I know it’ll fully lift it so long as I’m below 20mph, talking to a mate from my last job and one of the lads new to artics couldn’t get up a big hill by us, in a Volvo, turns out he was pressing the button at the traffic lights at the bottom, but you then get to over 20mph before the hill starts, so it was dropping back down, he didn’t realise so didn’t lift it again once below 20mph.

As said, if it’s possible load it heavy at the front. Anything behind the trailer middle axle is trying to lift the trailer at the front, but obviously you need to be within axle limits.

Where is your 5th wheel position? the further forward the it’ll move weight off your drive (and midlift when it’s down) to the steer.

Higher gear low revs works if momentum can get you over a hill, if momentum won’t take you over you need lower gears, higher revs, but with a part throttle position, usually just 1 gear lower than what truck could go up in, you need to be able to play with it, so as soon as it spins you need to ease off, then start gently building the revs up again, if you’re in a high gear low revs, you have nowhere to go with the revs and not enough power to ease off. If you have a turbo boost gauge, bring that up so you can see you’re not putting full boost into it. Making sure you’re in manual so the truck doesn’t decide to change at the wrong point.

If you have difflock don’t wait till you’re stuck to use it, use it so that you don’t get stuck on the hill, you can engage on the move so long as you don’t have wheel spin, so your wheels will be turning at the same speed, it’s not ideal for cornering as it’ll want to push straight and it increases the stress on the difflock, but you have to make a judgement call if theres corners on the hill.

Turn traction control off, as sometimes you know with the bit of spin it’s going to make it over the top, then TC cuts in dropping the power and you come to a stop, again read the book, I know on a Volvo it’s a 2 stage thing to completely turn it off.

If you get stuck drop the air out of the trailer suspension, raise the unit suspension, on a fully, uniformly loaded trailer it’ll transfer around 2t to the drive axle, more weight = more grip and if you’re turning it’ll also take away the scrub from the trailer axles.

8

stu675:
At what speeds do you get wheelspin? I find that I can re-engage cruise control below 10 mph. In fact you can come to a complete stop and pull away again with it still engaged and cc doesn’t produce much wheelspin. (I also never lower my midlift).

You can’t use both at the same time, midlift raised and weight transfer. If the midlift is raised which magic place is the weight being transferred from ? I don’t know if the weight transfer would actually lower the midlift if it was raised?

Is the light always on saying the axle is up (assuming the is a light on the dash)?

There is no weight magicaly appearing or disapearing its all about spreading the load. lets suppose you have a beam supported in the middle by a stack of books on flat ground. If you stand on that beam with each leg either side of the stack all your weight will be transfered to the ground through the stack of books. If you add another stack of books and move the first one so the beam is supported either end and stand in the middle then half your body weight will go through the stack on the left and half through the right hand stack. the more stacks of books you add the more you share the weight on each stack ie for x number of stacks the weight on each number of stacks is weight/x

I could be wrong with this but i assume the weight transfer button lifts or lowers the susspenstion slightly so there is more weight on the drive axle. Using the example above if you have the three stacks of books but stand between the first two then there will be more weight on the first two stacks than the third.

Thats why at least the mercs at work allow you to use the weight transfer button and raise the midlift at the same time

Hope im not teaching you to ■■■■ eggs or come across as condersending just trying to explain it simply

9

cooper1203:

stu675:
At what speeds do you get wheelspin? I find that I can re-engage cruise control below 10 mph. In fact you can come to a complete stop and pull away again with it still engaged and cc doesn’t produce much wheelspin. (I also never lower my midlift).

You can’t use both at the same time, midlift raised and weight transfer. If the midlift is raised which magic place is the weight being transferred from ? I don’t know if the weight transfer would actually lower the midlift if it was raised?

Is the light always on saying the axle is up (assuming the is a light on the dash)?

There is no weight magicaly appearing or disapearing its all about spreading the load. lets suppose you have a beam supported in the middle by a stack of books on flat ground. If you stand on that beam with each leg either side of the stack all your weight will be transfered to the ground through the stack of books. If you add another stack of books and move the first one so the beam is supported either end and stand in the middle then half your body weight will go through the stack on the left and half through the right hand stack. the more stacks of books you add the more you share the weight on each stack ie for x number of stacks the weight on each number of stacks is weight/x

I could be wrong with this but i assume the weight transfer button lifts or lowers the susspenstion slightly so there is more weight on the drive axle. Using the example above if you have the three stacks of books but stand between the first two then there will be more weight on the first two stacks than the third.

Thats why at least the mercs at work allow you to use the weight transfer button and raise the midlift at the same time

Hope im not teaching you to ■■■■ eggs or come across as condersending just trying to explain it simply

Weight transfer reduces the pressure in the midlift suspension, so putting more weight on the drive, lifting the the midlift if it allows is just the ultimate weight transfer

10

stevieboy308:

cooper1203:

stu675:
At what speeds do you get wheelspin? I find that I can re-engage cruise control below 10 mph. In fact you can come to a complete stop and pull away again with it still engaged and cc doesn’t produce much wheelspin. (I also never lower my midlift).

You can’t use both at the same time, midlift raised and weight transfer. If the midlift is raised which magic place is the weight being transferred from ? I don’t know if the weight transfer would actually lower the midlift if it was raised?

Is the light always on saying the axle is up (assuming the is a light on the dash)?

There is no weight magicaly appearing or disapearing its all about spreading the load. lets suppose you have a beam supported in the middle by a stack of books on flat ground. If you stand on that beam with each leg either side of the stack all your weight will be transfered to the ground through the stack of books. If you add another stack of books and move the first one so the beam is supported either end and stand in the middle then half your body weight will go through the stack on the left and half through the right hand stack. the more stacks of books you add the more you share the weight on each stack ie for x number of stacks the weight on each number of stacks is weight/x

I could be wrong with this but i assume the weight transfer button lifts or lowers the susspenstion slightly so there is more weight on the drive axle. Using the example above if you have the three stacks of books but stand between the first two then there will be more weight on the first two stacks than the third.

Thats why at least the mercs at work allow you to use the weight transfer button and raise the midlift at the same time

Hope im not teaching you to ■■■■ eggs or come across as condersending just trying to explain it simply

Weight transfer reduces the pressure in the midlift suspension, so putting more weight on the drive, lifting the the midlift if it allows is just the ultimate weight transfer

so why does it allow both at the same time?

11

No idea, not driven a merc in Years!

It might be that it’ll only lift upto a certain weight or speed, but you can use weight transfer at any weight / speed.

I just have 1 button in the Volvo

12

Having two lights up on the dash, doesn`t mean two things are happening.

Lift the axle, then push wt/trans button.
Maybe a light flashes, but does any air get dumped, or anything else?

It`s probably just protecting itself from having someone keep stabbing a button repeatedly.

13

Franglais:
Having two lights up on the dash, doesn`t mean two things are happening.

Lift the axle, then push wt/trans button.
Maybe a light flashes, but does any air get dumped, or anything else?

It`s probably just protecting itself from having someone keep stabbing a button repeatedly.

good point

Out of intrest i will have to get out and look see if the wheel is actualy up.

my thought process was along the lines of two people carrying a heavy box. if one is a lot taller than the other ie the box is tilted towards the shorter person then the shorter person is carrying more weight.

14

I found that having the eco type tyres on the drive axle, meant it had a tendency to spin up more rather than chunky M&S type which tend to have more grip.

Where your problem lies is not solely in the tyres, but the fact it is a Merc, and no, I am not taking the ■■■■. I always found they had a tendency to lose traction more than others.

Where they were better though, was when running solo, I used to turn off the traction control and drift the truck. ( That is a wholly fictional story, and should not be taken seriously…)

Ken.

15

cooper1203:
[

Out of intrest i will have to get out and look see if the wheel is actualy up.

.

That’s the midlift in the up position warning lamp, I find it is truthful in reporting when it is up or down.

16

You might be right in that it does something clever with the suspension regarding the height of the drive axle when you activate the weight transfer button? I just assumed that it only partially raised the mid lift, so that if it started in the up position, there’s nothing further that can be done.

17

ill have to wait till i am at work again im sure i have seen them both lit

18

Check drive axle tyre pressures, unless you run max weights 90psi is a nice pressure for the drive axle, even if you run max weights 100psi is fine, wouldn’t be surprised if your set is up somewhere around 120.

Good summary of things by Stevieboy as expected and Maoster and Quinny are right about typical fleet tyres, however we’ve been having snowflake and mountain stamped all season tyres for a couple of years now and i’ve not experienced drive axle grip like it, brilliant.

As for Mercs, i found the square Axor 2543 to be the best gripping tractor i’ve used in recent years, it just laughed at 6" of snow and it wasn’t cos pucka tyres cos they were any old remoulds however it did have a real gearbox which makes the world of difference, new shape Mercs i can’t bloody get on with, stupidly overtechnical and i’d find another job if had one of the poxy things foisted on me.
The last Merc i had to actually do a load or two with was a 65 plate, and i never did find any way to transfer weight off the mid lift, vehicle was about as much use as a chocolate fireguard, how they came up with such a successor to the generally competent square Axor i’m buggered if i know, gutless where the 2543 squarehead pulled like an old ■■■■■■■■

19

Just because I have a pic.

20

How does that work Stu? sensors on the valves or what?

What pressure are the drive axle supposed to be at, or are they all actually spot on 105 and it’s just sensor error?
I’d be dropping that nsr outer down a bit for sure.