What Causes Axle Tramp?

[C_W 3 1 Cars]

Normally when it's wet or a bit slippy like the roads are at the moment and I accelerate in 1st or 2nd and the wheels spin, it tends to be the left wheel that lights up due to having less weight over it I would have thought. And when it spins up it does it smoothly.

 

But for some reason at the moment when it wheelspins it seems to be the drivers side wanting to spin but it seems to do it jerkily and can sometimes bang a bit. It's not a suspension knock, it feels like the wheel bouncing a bit or something. I'm not sure whether this is since I've changed the gearbox or not. Is this what is called "axle tramp"?

[Wurzel 16]

I've always wondered why it did this. My old rear wheel drive Mk1 and 2 escorts used to do this terribly.

 

I always thought it was somthing to do with the rear beam and leaf spring affair, twisting. Since doing the same thing in a front wheel drive car, I'm now not so sure.

 

I wonder if it has anything to do with the length of the drive shaft on the drivers side and the way it's mounted on the block??

 

I'm sure some of the racers/suspension specialists will have a more useful answer.

 

It is the wheel bouncing/skipping as it releases it's energy (twisted forces), but why?

[Adi 0]

My old rear wheel drive Mk1 and 2 escorts used to do this terribly.

I always thought it was somthing to do with the rear beam and leaf spring affair, twisting.

 

Spot on......that is axle tramp. It is a form of wheel hop on live axle set ups with leaf springs. The axle rotates/twists slightly with the wheel and then springs back.

 

the length of the drive shaft on the drivers side

 

The unequal length driveshafts on fwd cars were known to be a contributary factor in torque steer. The long shaft on the o/s was modified on newer cars where there is a dummy shaft out of the gearbox......and then equal length shafts from there.

 

but it seems to do it jerkily and can sometimes bang a bit.

 

As the wheel spins and grips......the suspension bushes and engine mounts etc are taking the strain. The suspension also moves about both fore/aft and up/down violently. Unless everything is bolted together solidly......there will bound to be some knocking.

[jonnie205 1]

Nearly all front wheel drive cars will tramp unless they have propper rose jointed links and solid engine mounts. On my escort i put a full five linked rear suspension srtup in and that will reduce tramp. On my puma the engine is bolted directly to the body and there is no rubber in the suspension arms at all. Witgh 230 bhp that s what you need, also when tramp starts you are putting lots of load through the shell and all suspension components and drive shaft.

[C_W 3 1 Cars]

The thing is it normally spins up smoothly, just recently it seems to not want to.

[Adi 0]

just recently it seems to not want to

 

What about lower wishbone bushes?? What condition are they in?? And if they are Powerflex ones......that could be the prob.

[Bally 4]

As a matter of warning, when you get that axle tramp on the 205, and you do not have in an lsd, if you do it regularly, the diff will explode and make a mess of the gearbox. Trust me, invest in an lsd.

[C_W 3 1 Cars]

Is it a sign of the diff being worn or anything like that? Reason being is that the gearbox hasn't been on that long and before I could spin the wheels up nice and smoothly (always the passenger side wheel when just me in the car) and there would be no jolting or anything, but now I can feel the drivers side wanting to spin and it seems to bounce and bang a bit.

[C_W 3 1 Cars]

The bushes are fine and are standard ones. The passenger arm is brand new after the front bush failed and made it lurch about under acceleration and braking.

[richt 0]

umm got me worried, now my 205 does it and 309 used to do it. It only happens if i get alot of wheelspin, a small amount and its not to bad. In all the rain we had the other day and i bit of a quick get away and she was banging up the road. Didnt really worry to much as the 309 goodwood used to do the same. In all honesty its only the second time its ever been like that since i have had the car. My 306 on the other hand spins its wheels and it feels very smooth and not violent and banging like the 205 does.

[Beastie 1]

It may be a problem but by definition it isn't axle tramp which is a term that applies only to beam axles and not independent suspension.

[Adi 0]

by definition it isn't axle tramp which is a term that applies only to beam axles

 

Axle tramp won't happen on beam axles......as beam axles don't transmit power. Only live axles transmit power.

[NickR 10]

Bumps in the road ?

 

Roads tend to be more potholed on the left (Curb) ?

 

It IS the wheel bouncing and something must be causing (or not preventing) the wheel to bounce.

 

Dampers okay ?

[Beastie 1]

Axle tramp won't happen on beam axles......as beam axles don't transmit power. Only live axles transmit power.

Okay - fair point but it's a terminology one. In engineering terms a live (solid) rear axle is a beam. And I agree with you: It's these which can tramp However, if you've ever driven a 1920s beam front axled car hard over poor ground then you may find that beam front axles suffer from a very similar syndrome!

[Adi 0]

Okay - fair point but it's a terminology one

 

 

all front wheel drive cars will tramp unless they have propper rose jointed links

 

As Jonnie says......unless the front arms are rose jointed.....the arms themselves will try and twist as the wheel spins/tyre grips.

Now if you look at the design of the lower wishbones on the newer 206......they have moved away from the wishbone shape.......to an L shaped arm.....simply cos it won't try and spin as much......and the fore/aft movement will be more controlled.

The only other way to reduce the effect is to uprate all the mounting bushes, both on the suspension and certain ones on the engine.

[C_W 3 1 Cars]

Bumps in the road ?

 

Roads tend to be more potholed on the left (Curb) ?

 

It IS the wheel bouncing and something must be causing (or not preventing) the wheel to bounce.

 

Dampers okay ?

But it's the right hand (drivers wheel) doing it. When the passenger one used to spin (with less weight over it I assume) it was nice and smooth.

[NickR 10]

That IS odd.

[red 0]

Mines been doing this progressivley getting worse as the season goes on, I thought it may be somthing to do with the top rubbers being very tired as mine are and the spring and shock resonate at a certain speed and are both a little tired, the near side wishbone is bad as well, I run Group N engine mounts which are all fine and the Quaife atb diff, if you get someone to look at the front you can see the wheels bouncing violantly.

 

Regards Russ.....

[gareth 0]

i've had a fair bit of experience with this on both rwd escorts (like nickr) and on several fwd cars. (inc mini & vw scirocco)

 

my old escort rs2000 used to tramp even with the (standard) anti tramp bars fitted but when i replaced all leaf spring and anti-tramp bar bushes, the problem disappeared. it also made a massive difference to the handling.

 

with my scirocco, it used to torque steer violently and 'tramp' badly too. the same cure was tried (replaced all front end bushes with polyurethane) and the problem was reduced but still there. i then replaced the engine and gearbox mounts with new standard ones and the 'tramping' went.

 

the mini has a reputation for having an engine that's not keen on staying put and almost all tuned minis have been fitted with an engine steady. this is an extra support that runs from the bulkhead to the cylinder head reducing engine movement.

 

i would try removing the bonnet and with a passenger to observe, (on a private road of course!!) provoke the 'tramping' and watch how much the engine throws itself around in the engine bay. it's terrifying!!!

 

have you got an uprated lower engine mount? this combined with the drivers side top mount buffers is the way the engine is stopped from freely rotating in the shell so if they are getting tired it won't help things at all.

 

am i right in thinking you've got an mi16? if so, the mounts are going to get a lot more of a hammering than thay were designed for.

 

the other things to check, especially if the problem happens mainly on one side, are the condition of the shocks on the front. my gti only ever 'tramped' whan i first bought it and the shocks were dead. a full new set sorted this in one hit.

 

hope i've given you some more brain storming material and you get it fixed, in the meantime try not to let it happen often as it will put massive shock loads though the gearbox, diff and cv joints and will wreck them in no time.

 

between me and my mates, when we all used to have 1300 mk1/2 escorts without anti-tramp bars we blew up an average of 5 gearboxes each! they go bang by stripping all of the teeth clean off firts gear! i can now change the box on an old escort on my own in 30 mins, or the record stands at 12 mins with assistance!

 

good luck mate

 

gareth

 

EDIT: (as if this post isn't long enough, apologies to anyone who fell asleep!!)

 

something else to check is the strut top rubbers.

Edited January 26, 2004 by gareth

[C_W 3 1 Cars]

The shocks are brand new koni adjustables and with a new top mount set. Engine mounts are all fairly new too.

 

I'll see what it's like next time I drive it when it's damp, I don't know I may have been going over rough roads like nickr suggested each time it happened.

[Guest sillypugger]

SAAB 9000 turbo's suffer from this and it's cos the lower rear engine mount (hydraulic) splits and leaks.

 

mega common problem.

 

new mount always solves it.

[C_W 3 1 Cars]

OK, somethings definately not right with it as its pretty much refusing to spin the left wheel as it would normally. It was even trying to spin the drivers wheel setting off with some left hand lock on!!!

 

And with the snow setting off you normally expect it to feel so smooth you can't feel it but it's jerking and knocking. Seeing as I did the clutch last weekend and it was ok before, I need to check the front end.

 

Though driving it normally it drives fine as long as it doesn't wheelspin

[richt 0]

Mine seems to be down to the road suface, have lost traction a few times in the last day or so, and its been smooth.

[C_W 3 1 Cars]

Even on smooth snow it was jerking about It was worse because it's almost impossible to set off in a 205 on F1s in the snow without wheelspinning.

[NickR 10]

Are any of the brakes binding ?

 

Are the wheels balanced ?

 

Also, are your wheel bearings/hubs all free and working correctly ?

 

Finally is your tracking spot on ?

 

Excess Toe In can cause wierd effects on driven wheels, maybe ?