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Axle tramp?


Jon White
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Ok.......

Dont really understand here to be honest.........its a bit beyond me!

I'm suffering with front axle tramp on my series when going up steep climbs (diffs locked) which I suspect is whats casuing my trucks appetite for front axle components.

Question is what can i do to reduce this?

Its on 2 leaf parabolics, with ES3000 shocks, and runs 1 tonne shackles, and I've ground the spring pads to correct the castor. Shocks have been moved up (top and bottom mounts) by about 4" to improve ground clearance.

A mate of mine has suggested I need shocks with stiffer rebound damping, but the same compression damping as I have now. Does anyone know if maybe swapping to ES9000's on the front would have this effect? I'm also wondering if maybe my re-positioning of the shock mounts hasnt helped....

Also would lowering tyre pressures reduce tramp?

And for the record, its staying on leaves so thats not a valid answer! Any suspension guru's out there?

Thanks

Jon

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Its likely to be one of two things Jon

under damping leading to tramp

or..... spring wrap

I dont think (as you havent radically changed any geometry) that theres likely to me anything more than that

tackling underdamping would be my first suggestion (easy solution - fit 9000's or alternative)

tackling spring wrap is a bit more long winded but if you speak nicely to mr Fridgefreezer he may even post some pics of the setup thats going on his (on next weekends list) a simple radius arm job doesnt allow for the suspension to cycle correctly as theres fore and aft movement as well as rotation to deal with - a custom arm (akin to a radius arm) but with a heim joint joining to a spring hanger takes care of the chassis end, stock bushes at the fork ends will deal with shock load - couple of lugs onto the axle tube and bobs ya monkey, its not a major fab but try the dampers first! ;)

HTH

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Jon,

Bill had some god ideas on this that might be worth trying. It involved reversing the front springs placing the hangers at the front.

Think he's on hol at the moment but try a search. Did seem to make sense.

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The back end has more weight over it, so yes it will be more inclined to stay put.

One option, if it's axle wrap, is to add a leaf, this stops the axle rotating. It's more of a problem on paras than standard spring packs as it would take a lot to twist a LR spring pack!

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hmmmmm food for thought there..........shame no-ones actually tried it out yet!

Dont really want to get into adding a leaf, as my suspension is nice and compliant and dont want to lose articulation.

Interestingly this might be why tonk doesnt have the problem as his truck is so lardy! The v8 weighs a fraction what his oil burner does!

Jon

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The shackle reversal thing sounds good in theory, wonder why some vehicles do it one way and others another? My only theory would be that with leading shackles it could cause a bit of steering vaugeness as the front of the spring would be more inclined to move, whereas with the shackles trailing they will go along with whatever the front is doing.

LR must've had a reason to change it way back in 1948 :huh: as Bill states "most suspension designers don't know either" I'm sort of wondering if in fact they know something we don't :unsure:

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As above really.

Es9000's will help a lot.

Are you suffering any problems with u bolts coming loose? As it could be that the spring seat is worn as well.

The devise that jez is refering to is generally refered to as an anti-wrap bar or ladder bars they are quite popular in the states, so a googlesearch might find you some pics.

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The shackle reversal thing sounds good in theory, wonder why some vehicles do it one way and others another? My only theory would be that with leading shackles it could cause a bit of steering vaugeness as the front of the spring would be more inclined to move, whereas with the shackles trailing they will go along with whatever the front is doing.

LR must've had a reason to change it way back in 1948 :huh: as Bill states "most suspension designers don't know either" I'm sort of wondering if in fact they know something we don't :unsure:

my understanding is that the early 80in had leading shckles but that there were issues with vague handling (on a series?) :o so they swapped it to the rear of the front spring. There was some cause given but i can't recall it at the moment something to do with wear but 'tis filed away in the dim and dusty recesses of my mind

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just an idea but if its leading shackle then as the suspension compresses ie hitting a bump at speed the axle would have to travel forwards placing further load on the spring either showing itself in spring failure or more wrap?!? with trailing shackle the axle (as it cycles) will move in the same direction as the impact

god knows - Im only guessing :)

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There's a pretty good tech writeup here: 4x4Wire Anti-wrap tech, I'm rapidly coming to the conclusion that many of Pirate4x4 wouldn't know one end of a hammer from the other yet are prepared to recommend all sorts of dumbass solutions, including chains, wire rope, and other bizarre contrivances.

The most common solution in the states is the traction bar / ladder bar:

post-21-1164195216_thumb.jpg

Sam's Offroad Traction Bar

A remarkably similar version for Toyotas:

BudBuilt_traction_bar_1s_small.jpg

www.budbuilt.com/new/traction_bars.html

Pirate 4x4 ugly but effective fab job by Billavista

The only other one that I can make out as being a reasonably sensible solution is the Bam Bar:

t_DCP_0891.JPG

http://www.jeepaholics.com/tech/bambar/

Going on the grounds the most simple/obvious solution is probably the best, the traction bar looks like a good bet and is what I'm going with on mine.

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88" series, on series axles, carbed V8.

Running ARBs front and rear, and rims are reversed 8 spokes giving 6" of back spacing.

Need any more info?

Ta!

Jon

My 86" series 1, v8, twin lockered, parabolics, 8 spokes, es3000

had exactly the same problem, the es9000's will help tremendously, also, I fabricated twisty front shackles, they reduced it even more.

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Ok.......

Dont really understand here to be honest.........its a bit beyond me!

I'm suffering with front axle tramp on my series when going up steep climbs (diffs locked) which I suspect is whats casuing my trucks appetite for front axle components.

Question is what can i do to reduce this?

Its on 2 leaf parabolics, with ES3000 shocks, and runs 1 tonne shackles, and I've ground the spring pads to correct the castor. Shocks have been moved up (top and bottom mounts) by about 4" to improve ground clearance.

A mate of mine has suggested I need shocks with stiffer rebound damping, but the same compression damping as I have now. Does anyone know if maybe swapping to ES9000's on the front would have this effect? I'm also wondering if maybe my re-positioning of the shock mounts hasnt helped....

Also would lowering tyre pressures reduce tramp?

And for the record, its staying on leaves so thats not a valid answer! Any suspension guru's out there?

Thanks

Jon

AXEL TRAMP!!!!!!!!! WASN'T HE A SCANDINAVIAN VAGRANT!!!!!!!!! :D

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mine suffers from leaf wrapping underbraking, and im running es9000 <_<

thats what you get for having rangie vented disc brakes.

Wanna swop?

i was planning on using a damper as a kind of thrid link, as the position for ridgid bar with out imposing flex would be some where rediculous. no idea if it would work, but its gotta be worth a try

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John,

I can see the way those traction bars are supposed to work, but all seem aimed at rear axle problems.

To do the same on the front axle would surely require the bars to be mounted onto the front of the front axle with the bars running forwards. Would then end up very short and difficult to mount surely?

I've not had any problems under braking (disks all round).

898KOR - when you say twisty front shackles, so you mean revolver type shackels that fit to the rear ends of the front springs, or do you mean flexy front mounts like thos egon-2-far were doing?

Sounds like the ES9000's would be a good first step anyway thats easy to do!

Cheers

Jon

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