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live axle question
daniel mason - 18/9/09 at 08:31 PM

how does a live axle affect handling in a negative way? the reason i ask is that a lot of sprint/ hill climb cars seem to be live axle eg strikers, but still seem very very quick,even compared to other far more expensive machinery!

snapper - 18/9/09 at 08:48 PM

Can of Worms....

mookaloid - 18/9/09 at 08:52 PM

live axles are noticeably quicker off the line so are ahead from the start.

not sure about the negatives, but I presume that you mean that they can't be adjusted like an independent rear end and they will be slightly heavier.

franky - 18/9/09 at 08:52 PM

quote:
Originally posted by daniel mason
how does a live axle affect handling in a negative way? the reason i ask is that a lot of sprint/ hill climb cars seem to be live axle eg strikers, but still seem very very quick,even compared to other far more expensive machinery!


When I looked into it I was told the same way IRS affects it in a negative way...... 6 of one, half a dozen of the other.

D Beddows - 18/9/09 at 08:54 PM

Mostly by not being very fashionable or 'modern' enough tbh

To be serious what it tends to mean is that generaly speaking a live axle is just as good as irs on smooth surfaces like race tracks but not quite as good on bumpy surfaces like roads. It does depend a HUGE amount though on how well your suspension has been set up and it's much easier to get irs wrong than a live axle....

As has been mentioned it's a huge can of worms

[Edited on 18/9/09 by D Beddows]

Canada EH! - 18/9/09 at 09:57 PM

Biggest problem, unsprung weight, followed by movement of the suspension on one side effecting the other side.
Good side a lot less pieces to go wrong, and most of them not in the environment, and a lot less work to mount.
As said great on a smooth surface.
New Mustangs still have live axles because that's the way the drag racers want it.

JimSpencer - 18/9/09 at 10:00 PM

quote:
Originally posted by D Beddows
To be serious what it tends to mean is that generaly speaking a live axle is just as good as irs on smooth surfaces like race tracks but not quite as good on bumpy surfaces like roads. It does depend a HUGE amount though on how well your suspension has been set up and it's much easier to get irs wrong than a live axle....


Hi

I would agree with that, running a live axle Striker (1988 ish vintage)

Though perhaps the last bit should be the other way round:-
It's much easier to get a live axle right than IRS

Plus I think (give my limited experience) the operating window is bigger.
A live axle, set up vaguely right, will still be OK ish, wheras the IRS seem to need to be spot on (and when they are it's very quick indeed) - but that might just be some of the folk I've come up against.

Saying all that, if it was just for road use then IRS it would be everytime

NS Dev - 18/9/09 at 10:24 PM

pretty much as above.

The single limiting factor for a decent, well set up live axle, is bumps!

Even then it depends on the car its attached to.

Think about the axle and the car as two weights connected by a spring.

If the car weighs MUCH more than the axle, then the axle will be forced to comply, if the car weighed less than the axle (simplified I know, its only the part weight of the car but keep it simple! ) then the axle would "be boss".

The problem therefore is sprung to unsprung weight ratio.

lighter cars make it tricky

Live axles on a racetrack are generally very effective though!

redscamp - 18/9/09 at 11:42 PM

a live axle slides in a progresive way.
irs lets go with a bang.

daniel mason - 19/9/09 at 08:57 AM

thanks for the replies guys!