scootz
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| posted on 9/9/10 at 07:39 PM |
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Live-Axle, De-Dion, IRS...
Anyone want to have a stab at the pro's and con's of each different set-up?
Only as it applies to real-world road-use...
It's Evolution Baby!
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nick205
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| posted on 9/9/10 at 07:46 PM |
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I'll bite...
Live Axle:
+ Relatively easy to achieve good geometry
+ Simple and effective
- High unsprung weight
- Can be upset on uneven surfaces
IRS:
+ Low(er) unsprung mass
+ Better ride on uneven surfaces
- Much harder to achieve a good design as more variables
De-Dion:
Somewhere between the two above?
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mcerd1
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| posted on 9/9/10 at 07:47 PM |
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^^ and you get a torque reaction with a live axle that causes the body to roll when you let you foot off the clutch (as the axle reacts against the
chassis throught the springs)
on dedion and IRS the diff is mounted to the chassis so the reaction is just another load in the chassis (i.e. no body roll)
on nice flat surfaces its easy to setup dedion and IRS and the wheels stay nice and flat to the ground regardles of what the body does above it
as the body rolls on an IRS the camber of the wheels changes...
here's dax's explanation:
have a read of this: http://www.carbibles.com/suspension_bible.html
[Edited on 9/9/2010 by mcerd1]
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fesycresy
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| posted on 9/9/10 at 07:54 PM |
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Have a read of this.
De Dion vs IRS
-----------------------------------------------------------------------------------------------------
The sooner you fall behind, the more time you'll have to catch up.
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scootz
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| posted on 9/9/10 at 08:12 PM |
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Cheers guys!
It's Evolution Baby!
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StevieB
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| posted on 9/9/10 at 08:33 PM |
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I'm interested in the same subject at the moment.
I had been pondering whether to retain a live axle in my midget, with a conversion to 5 link or do an IRS conversion. deDion puts an interesting
alternative in the mix which should be a simpler conversion than IRS.
However, would it really make a big difference to the car over retaining a live axle?
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scootz
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| posted on 9/9/10 at 08:45 PM |
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It's that 'real-world' aspect that I'm most interested in... competition use is one thing, but would I really notice the
difference between the 3 whilst back-road scratching?
It's Evolution Baby!
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interestedparty
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| posted on 9/9/10 at 09:03 PM |
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quote:
Originally posted by scootz
It's that 'real-world' aspect that I'm most interested in... competition use is one thing, but would I really notice the
difference between the 3 whilst back-road scratching?
You would certainly notice the difference between the live axle and the other two, mostly in how bad the thump was when you went over a ridge or
similar, and if you were generating some sideways force at the same time, you might even jump sideways a bit (can be fun, though)
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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mangogrooveworkshop
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| posted on 9/9/10 at 09:59 PM |
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Still crash them the same.......
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twybrow
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| posted on 9/9/10 at 10:55 PM |
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My live axle is incredibly compliant and rides very well over rough surfaces (better than my tin top). It is all in the setup, a well setup live axle
will feel a damned sight nicer than a poorly setup IRS.
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MikeR
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| posted on 10/9/10 at 05:07 AM |
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I believe that comment has been echo'd by procomp a number of times. What was surprising for me was the lack of weight difference between
de-dion and live axle. I've gone de-dion and weighed everything (i posted this ages ago). There isn't a huge amount in it - although some
benefit.
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procomp
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| posted on 10/9/10 at 10:41 AM |
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Hi
As said above its all in the setup. The trouble is that most Kit manufacturers who fit a live axle just throw it in the back end with no thought to
geometry and then supply dampers that would be more suited to a JCB.
In the real world if you take a little care with the geometry and use a set of dampers that are valved to suit the application you can achieve a very
nice compliant ride on the roads. And still have all the advantages available when on the track.
Cheers Matt
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scootz
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| posted on 10/9/10 at 10:45 AM |
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Cheers all...
PS - Would you sat that an LSD unit was worth the £500 for a road going live-axle car Matt, or not really?
It's Evolution Baby!
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MikeR
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| posted on 10/9/10 at 11:19 AM |
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say no, say no, say no, pleeeeease ..... i don't need another excuse to delay / slow down my build!
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twybrow
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| posted on 15/9/10 at 09:53 PM |
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My LSD transformed my live axle. It took a while to get used to the back slipping, rather than spinning up a rear wheel, but you gain a whole new
level to the driving experience. I am no driving god, but I just love the way you can get the car moving on the exit from a corner!
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