Axle Tramp In R32 Gtst

[blind_elk]

First off, I think you need to confirm you actually have axle tramp.

My understanding is that the driven tyres lose traction when you apply too much engine torque to, and the wheels simply bounce up and down. It's far more comon in leaf spring setups. That is why I couldn't believe that new Bilsteins and Kings springs didn't solve the problem. And since no-one has actually seen what is going on when you get the "axle tramp" happening.

What did the guys at Traction have to say about the likelihood of you having "axle tramp"?

[Cain]

i thought axel tramping was when the tyres would toe in under acceleration and then spring back apart and "bounce"

[femno]

Pat as a last resort try fitting adjustable rear traction arms.

Youll need camber arms to go with them, and from my understanding you should lengthen the traction rods an amount to acquire more grip.

Have you fixed that vibration yet?

[-Jimmy-]

Just a thought, it could be your universal joints in the tailshaft? Or the tailshaft itself? I had a lot of bouncing around (like a constant shuddering until I had pretty much shifted into 2nd gear) under there when launching so got it up on a hoist and someone identified to me that it was the tailshaft bearing.

I went to get that replaced and they also ended saying that all the universal joints were rooted!

I ended up getting a 1 piece tail-shaft and this has fixed all my vibrations when launching.

Edited June 19, 2009 by -Jimmy-

[skylinecouple]

You have forgotten the basic laws of mechanical diagnosis, get the basics right then go from there. In other words your car is ancient in regards to your stock bushes so you might want to replace everything you can with urethane. I have said it before and will repeat it yet again, your differential is in the center so replace those bushes first. Every time this comes up the first thing someone suggests is the springs and shocks and yes it may well be but I can tell you now your differential bushes are flogged to death, replace them. Unfortunately it is a diff out situation for the rear bushes but at least do the front ones closest to the drive shaft. Think about how many times you accelerate and back off and how the diff goes up and down with it and you can see my point. If a stock car with new bushes everywhere doesn't axle tramp ( and yes I know some do but not skylines ) then right there is your answer, things have worn.

[Rekin]

What did the guys at Traction have to say about the likelihood of you having "axle tramp"?

At the time i went to show Traction Tyres, the roads were wet and they didnt want to test. Will go back to them once the roads dry up.

Just a thought, it could be your universal joints in the tailshaft? Or the tailshaft itself? I had a lot of bouncing around (like a constant shuddering until I had pretty much shifted into 2nd gear) under there when launching so got it up on a hoist and someone identified to me that it was the tailshaft bearing.

I went to get that replaced and they also ended saying that all the universal joints were rooted!

I ended up getting a 1 piece tail-shaft and this has fixed all my vibrations when launching.

Ive had the tailshaft pulled off and rebalanced so definitely not that, could be the surrounding joints/bearings though...

You have forgotten the basic laws of mechanical diagnosis, get the basics right then go from there. In other words your car is ancient in regards to your stock bushes so you might want to replace everything you can with urethane. I have said it before and will repeat it yet again, your differential is in the center so replace those bushes first. Every time this comes up the first thing someone suggests is the springs and shocks and yes it may well be but I can tell you now your differential bushes are flogged to death, replace them. Unfortunately it is a diff out situation for the rear bushes but at least do the front ones closest to the drive shaft. Think about how many times you accelerate and back off and how the diff goes up and down with it and you can see my point. If a stock car with new bushes everywhere doesn't axle tramp ( and yes I know some do but not skylines ) then right there is your answer, things have worn.

thanks for help.

I'll look into replacing the diff bushes.

Would anyone have part numbers of the specific bushes I would need to buy?

SuperPro SPF2637K RR Diiferential pinion mount bushing?

Any other bushes I should replace along with that?

Thanks all!

[thrtytwo]

coilovers come standard in skylines, so a bit more info into what the coilovers actually are might help lol

Tein super streets

[skylinecouple]

At the time i went to show Traction Tyres, the roads were wet and they didnt want to test. Will go back to them once the roads dry up.

Ive had the tailshaft pulled off and rebalanced so definitely not that, could be the surrounding joints/bearings though...

thanks for help.

I'll look into replacing the diff bushes.

Would anyone have part numbers of the specific bushes I would need to buy?

SuperPro SPF2637K RR Diiferential pinion mount bushing?

Any other bushes I should replace along with that?

Thanks all!

Not sure if that's the one but just ring the various bush suppliers and ask them to make absolutely sure. If you look under the diff you will see what I'm talking about. The ones at the rear are a pain as the hicas has to be unbolted and left to the side. I did this myself and takes a while to undo the drive shaft and axles but I kid you not, this totally eliminated my axle tramp.

I tried tyre first and that made it worse. Then springs and shocks, which helped a little. Replaced outside arm bushes after suspension proved to be giving too much positive camber, slightly improved but if on the edge of traction would shake violently. Was going to replace tie rods with rose joints but stopped off at a place with quite a few race cars out the front and made some inquiries, they said what I just did, start at the center and work your way out. As the old guy there said, "a building is only as strong as it's foundations". If you start with your tyres you will be chasing your tail looking for the culprit. Get the diff nice and solid first.

[femno]

Have you fixed that vibration yet?

You know? The one at 100kph?

[R32Abuser]

just because a suspension place fitted your springs and shocks doesnt necessarily mean that the shocks and springs are matched for one another, so i wouldnt quite knock option 4 on SK's list off...

Axle tramp is caused by oscilations in the vertical direction of the tire, spring and damper system. Majority of the time its caused by the shock absorbers lack of control in rebound to "dampen" these osciallations as SK has stated.

I too have this problem, have SK's full suspension kit and are looking for answers...my thoughts are leaning towards either my springs, or the position where my subframe bushes are placed. There are a few alternate configurations for these bushes to be arranged in and i believe my current setup is for "All round performance"...I would think positioning these bushes to achieve more squat (or reduce anti-squat) would be a cure, as to increase longitudinal load transfer (for and aft of the car) to the rear, and hence increase the vertical load on the rear tires. If i find a fix, ill let you know Renkin

[nisskid]

i can tell u, i still get axle tramp in my car which is running valving designed for springs up to roughly 7kg on the rear, and is only running 4kg springs, so well and truly damped. this was the same with when i ran 5kg springs on those shocks, 4kg on the standard B6 shocks, and when i ran just the kingies on the bilsteins.

at every height, etc etc. its never completely gone.

[Sydneykid]

i can tell u, i still get axle tramp in my car which is running valving designed for springs up to roughly 7kg on the rear, and is only running 4kg springs, so well and truly damped. this was the same with when i ran 5kg springs on those shocks, 4kg on the standard B6 shocks, and when i ran just the kingies on the bilsteins.

at every height, etc etc. its never completely gone.

There are plenty who don't get axle tramp, so there is something wrong with yours, you just haven't found it yet.

Cheers

Gary

[nisskid]

yeh, that's what im saying.

i also have urethane subframe bushes, soon to be pissed off and replaced with solid mounting. ive run the car at anywhere from 300mm to 400mm, ive run anywhere from 20psi to 45psi.

it's lucky i dont give a shit about it otherwise id do my head in trying to figure out what the problem is.

[Rekin]

just because a suspension place fitted your springs and shocks doesnt necessarily mean that the shocks and springs are matched for one another, so i wouldnt quite knock option 4 on SK's list off...

Axle tramp is caused by oscilations in the vertical direction of the tire, spring and damper system. Majority of the time its caused by the shock absorbers lack of control in rebound to "dampen" these osciallations as SK has stated.

I too have this problem, have SK's full suspension kit and are looking for answers...my thoughts are leaning towards either my springs, or the position where my subframe bushes are placed. There are a few alternate configurations for these bushes to be arranged in and i believe my current setup is for "All round performance"...I would think positioning these bushes to achieve more squat (or reduce anti-squat) would be a cure, as to increase longitudinal load transfer (for and aft of the car) to the rear, and hence increase the vertical load on the rear tires. If i find a fix, ill let you know Renkin

the shocks and springs were bought as a package from a suspension workshop. He sells plenty of packages for r33's/r32's so I have faith in his setup...As the problem didnt get better/worse after replacing from old suspension (kyb shocks w/ hks springs) I have a feeling its related to something other than shocks/spring setup...

Organising some diff bushes and will hopefully see some difference when replaced...

Will post details once they in

Thanks all

[blind_elk]

Well, you STILL haven't confirmed that you actually have axle tramp. It seems no-one has actually seen what is happening when you get "axle tramp". You have only felt something going on.

I just can't believe that brand new Bilsteins and springs are incapable of controlling the vertical motion of the rear wheels.

[yogi000]

i got the SK kit on my r32 gtst with subframe bushes.

i get lots of axel tramp....its definitely that jumpy motion.

Its so violent that i have to back of the throttle because it feels like something will break.

I can confirm that have the whiteline bushes inthe max traction postion made it worse. The all round setup seems to help but only slightly.

I've also run, nexen cheap tyres, Re55's, 595RS, 595SS. The issue is only slightly different with each of these tyres.

Car is at ~350mm

my 2 cents......i will look into the diff idea.

[R32Abuser]

hmmm I would have thought have a higher vertical load on the tire would improve the tramp. Drawing a diagram of the forces involved, if there is a higher vertical load on the tire acting downwards, for the wheel to oscillate or even travel upwards, the forces acting to push the wheel upwards would have to oppose a greater force downwards in this new subframe position. Strange :S

yogi have you tried the bushes in the opposite position, so in the max stiffness position (full anti-squat)? That might be something to try, however my thoughts would be that it may harm the traction of the car in all conditions of driving (wet, dry, damp etc). I find that i only get axle tramp in the wet, or in the dry when i put full boot into it doing a U turn.

[antonio]

pineapples.

[skylinecouple]

It may not be diff bushes but I'll wager it is. I have owned my car for 228,000 of it's 250,000k's and I know it backwards after three engines and sorting it out through every little problem of it's mods. I have removed and replaced so many parts I have forgotten a lot of what I've done. Diff bushes.

If you look on the LS1 or Harrop site you will eventually come across exactly the same problem which was solved by installing a Harrop diff brace. Makes for interesting reading. Stop wasting money on shocks and springs and different tyres. Although, there is another way to fix it, set up a diesel spray above your rear tyres and mount the tank in the boot. Axle hop cured.

[skylion]

I had the same problem with mine. did all the usual, springs, shocks (rebound and bump), tyres, pineapples in all positions, UJ's etc - no real change. Bought some Nismo HD engine mounts, 98% fixed. Still tramped a little but not the horrible banging in the rear and box. I know it sounds crazy but it worked for me.

J