axle tramp

[VN_Luke]

i was wondering what are the main causes of axle tramp?

on a car with a solid axle, spool, king spring lows, and monroe GT gas shocks.

decent condition rubber bushes in the rear...

axle tramps when at mid-throttle
but goes away when you mash gas?

[foammedia]

It shouldn't really happen on non leaf springs cars, it's caused by the diff rocking forward and back, on a leaf springs that makes the wheel start jumping off the road in a never ending crazy man cycle (see mustang take off in Bullitt for a good example ) The rear trailing arm bushes would have to be suspect number one

[commy92]

mate its casue you got a spool.... long ive the spool

[90VN55]

it happens in my brothers ute.
could it also be that there isnt enough weight in the back to push the car down

[VN_Luke]

mate its casue you got a spool.... long ive the spool

but it never did it with a properly working LSD...

I changed the whole diff housing, which includes the rubbers up the top of the housing.. but they all look in decent working order.

[VN_Luke]

haha I did a search for 'axle tramp'...and I found a post by me? amazing.

Well, i'm back and at it again - axle tramping all over the joint

has anyone had success with getting rid of tramp? Adjustable upper arms maybe?

[HoZy]

I used to get axel tramp in the VQ but that was IRS.... So hmmm Never heard of many people getting axle tramp on a live axel... You got a twisted axel spline thanks to the spool maybe?????????

[stocky]

he doesnt have a spool

[HoZy]

he doesnt have a spool

Your blind rnt u. read the first post

[VN_Luke]

Sorry - changed cars since 2006 when this was posted - I just didn't want to put up another thread with the same title LOL

yeah this is in the new car now:

- lokka,
- new nolethane bushes all round,
- k-mac fe2 height springs,
- monroe gas shocks,
- whiteline rear sway bar,
- whiteline adjustable panhard rod
- 15x7" wheels, with 225 wide rubber on them.


I don't know if axles can warp at the splines? or would they just sheer/snap?

and a bent axle usually shows itsself in ruined brake pads on one side and constant annoying squeeking... and as far as I know these have never been bashed against gutters or anything like that

people seem to blame upper control arms for tramp, and replace with harder bushes and presto! but seems to not work in my case

[immortality]

normally i'd suggest the top trailing arm bushes. seems to be fairly common.

poor quality/stuffed shocks can also be a problem but you have covered these things. i found i was getting axle tramp when i first fitted the rebuilt LSD. either totally backing of the gas whilst cornering was one solution, the other was giving lots more throttle (and more fun)

when i lowered it and fitted new shocks the problem dissapeared mostly although i still need to do top trailing arms as well. (had munroes in that were less then 20,000km old)

[stocky]

lol hozy = pwned

[VN_Luke]

normally i'd suggest the top trailing arm bushes. seems to be fairly common.

poor quality/stuffed shocks can also be a problem but you have covered these things. i found i was getting axle tramp when i first fitted the rebuilt LSD. either totally backing of the gas whilst cornering was one solution, the other was giving lots more throttle (and more fun)

when i lowered it and fitted new shocks the problem dissapeared mostly although i still need to do top trailing arms as well. (had munroes in that were less then 20,000km old)

Thanks for the suggestions & thought.

I'll get under there and tripple check that nothing is loose/mis-seated.

After that I think I'll replace the shocks, as they seem to function fine (the ol 'press the car') trick, but i'm unsure of their age..

I've heard about 'coil over' setups for the rear of commodores, has anyone had any dealings with these??

[immortality]

they reffer to a "coil over" for the rear of the commodore but it's not really a true "coil over" at all. the suspension is as per normal but they put adjustable platforms under the springs between the lower trailing arm and spring. the shock stays as per normal. i have seen a true coil over for a commodore here in NZ but it requires altering the shock mount on the axle as well as the the body mounting point to strenghten em as they were never designed to cary the full load of the rear of the car

[VN_Luke]

they reffer to a "coil over" for the rear of the commodore but it's not really a true "coil over" at all. the suspension is as per normal but they put adjustable platforms under the springs between the lower trailing arm and spring. the shock stays as per normal. i have seen a true coil over for a commodore here in NZ but it requires altering the shock mount on the axle as well as the the body mounting point to strenghten em as they were never designed to cary the full load of the rear of the car

Ah I get you.... so really, it's just an adjustable height spring - which would probably be quicker to change over than adjust anyway! I'm guessing...

There's also adjustable upper arms available, to correct the pinion angle on launches and acceleration - but from what I understand, tramp is caused by 'twisting movement' (i.e. the top of the diff going fwd and back) then just gets amplified? so adjustable arms wouldn't really help (for tramp anyway!)

You think maybe shocks could be more likely to hide the 'symptoms' of tramp? rather than resolve the problem?

Any ideas on how to reliably check for movement/flex in rear suspension parts?

[HoZy]

Lol sorry stocky didnt realise date of first post...

An luke i've seen twisted axel ends... where the spline is twisted a good 30degrees but i dont know if its likely to say its got anything to do with this.. A reason, not enough weight in the back end, tyres out of round, trailing arm bushes, shocks... Rear uni on tailshaft giving an axel tramp effect...
ROAD SURFACE?? Panhard rod too far to one side?

Theres so many factors.... its near scary... Your springs just might not be able to cope with it, i havent seen many tough as guts cars on standard fe2 springs... but i can be very mistaken there..

[immortality]

Ah I get you.... so really, it's just an adjustable height spring - which would probably be quicker to change over than adjust anyway! I'm guessing...

There's also adjustable upper arms available, to correct the pinion angle on launches and acceleration - but from what I understand, tramp is caused by 'twisting movement' (i.e. the top of the diff going fwd and back) then just gets amplified? so adjustable arms wouldn't really help (for tramp anyway!)

You think maybe shocks could be more likely to hide the 'symptoms' of tramp? rather than resolve the problem?

Any ideas on how to reliably check for movement/flex in rear suspension parts?

yeah, the new (and better) KYB shocks possibly disguise the symptoms but i know that my original factory rubber bushes are suspect. my munroes also felt fine with the car "bounce" test and also nice and firm when removed from the car when compressed or extended by hand. better shocks would help to stop that occilating movement that is axle tramp (i also lowered the car at the same time on superlows which are a lot firmer then standard springs)

the only real way would be to put the car up on a hoist and start pushing/pulling(maybe use a bar) at the suspension parts to see what moves. not sure how good the pedders "drive on" suspension test is. it might show where there is movement

[Emackulation]

Why do tramps always go for the guys named Axel in the first place is my question?

[immortality]

Why do tramps always go for the guys named Axel in the first place is my question?

good to see Mack asking the serious questions

[vnv8driver]

if its not the shocks you need to find out whats making the rear wheels jump up and down. most of the time its due to shot shockies, i know there new but maybe take them out and test the travel rate in them.

[thestig]

Reaper elliminated his tramp with springs that are not tapered toward the end of the coil. I am planning to do the same with my calais as the b*tch is bouncing all over the place!

See here for pictures:-

Reapers Black VP SS

L8r

[STEALTHY™]

I used to get axel tramp in the VQ but that was IRS.... So hmmm Never heard of many people getting axle tramp on a live axel... You got a twisted axel spline thanks to the spool maybe?????????

I've had the opposite. My mates VN SS (solid) axle tramps like crazy. Mine only does it if its wet and i give it 5000rpm. Normal burnouts etc, never had axle tramp with the IRS

[kniever]

when i had the mini spool in with new shocks and new springs it used to tramp bad and then when i got lsd put in after that ive never had tramp again.

it must be just cos the diff is locked cos mine was doing exactly what u explained before i changed to lsd

[immortality]

I've had the opposite. My mates VN SS (solid) axle tramps like crazy. Mine only does it if its wet and i give it 5000rpm. Normal burnouts etc, never had axle tramp with the IRS

get your mate to check his top trailing arm bushes, these are normally the culprits. even my diff guy said if i got axle tramp to change mine.

certainly lowered cars with much firmer springs would be better because it takes more force to overcome the springs/shocks to cause the axle tramp

[Benboy]

Obviously something dramatically wrong with your driving style. I have driven VN's 100's of thousands of KM and never experienced the problem once. Perhaps you are just flogging your car much too hard. Remember they are now some 20 yrs old and just won't take a hammering.