Board Logo

IRS vs Swingaxle
ronster - May 4th, 2004 at 04:18 PM

Hi all,

A couple of questions...
In a nut shell, what's the difference between IRS and Swingaxle rear suspension?

Do all post 68 beetles and superbugs have IRS rear end?

Thanks!
Ron


Che Castro - May 4th, 2004 at 04:59 PM

Anyway in a nutshell - when the wheel goes over a bump with a swing axle, the wheel moves in an upward arc where the centre is at the transmission. This causes the wheel camber to change during the suspension travel.

in "IRS" the wheel travels more or less vertically in a straight line

IRS came first in 1968 on only the Semi Auto models (which were all fully imported from germany, the other aussie beetles were assembled here from german parts).

From 1972 the Superbug was available (which had IRS and macpherson struts) and from 1974 the Superbug L was available (aka. 1302 and 1303 respectively). There was an econo version called the "standard" which had swing axle and a 1300 twin port.

this website explains it better

http://www.vwclub.com.au/vwhistory/austmodels.htm

p.s. not to be anal but the swingaxle is actually independent suspension too :D :D :D

[Edited on 4-5-2004 by Che Castro]


killakornkobb - May 4th, 2004 at 07:40 PM

when here in Oz only semi-autos had the IRS (and double belt windows) all beetles in the US/Germany had the IRS.. so easier to get one there than here.. there is always a semi-auto in the trading post though :) and theyre a LOT of fun to drive

---Damien


BiX - May 4th, 2004 at 08:03 PM

wasn't it about 69 70ish they went to IRS? all the supers had IRS


68AutoBug - May 4th, 2004 at 08:27 PM

No Bix ,
the only standard Beetle to have IRS was the 1976 Beetle .. Our last Beetle... all other standard Beetles in Australia had swing axles [also IRS] and Front drum Brakes..
Excepting the Auto Stick Beetles from 1968>....
[as mentioned before] ..
The 1971> 1302S Supers & 1973 1303S Supers both had IRS rear suspension...

Just to make it confusing, all Beetles have had 4 wheel Independant Suspension.....
its just that some have IRS [swing arms] & others [swing axles] don't... is that confusing or Not???
For this Exercise - an IRS = CV Joint rear axles...

Lee --


56astro - May 4th, 2004 at 09:50 PM

And to make it even more confusing, the manuals use the terms;

"Diagonal arm axle" = IRS

"swing axle" = as the name suggests, durr

:P


silver - May 4th, 2004 at 09:57 PM

Gee Lee! your going to be cold in winter without those heater boxes!
Silver


68AutoBug - May 4th, 2004 at 10:59 PM

IYes, We have had temps down to 12-13 last few nights...
and 3-4C some mornings... but I wait for the sun to come up before getting out of Bed...
I do Have two New Heater boxes to go on My engine....
I haven't decided on what colour to paint them yet, in High Temperature paint... Maybe silver or white... and standard exhaust with one 2 inch exhaust coming out from under a guard...

Lee...


lugnuts - May 5th, 2004 at 02:24 AM

Quote:
Originally posted by silver
Gee Lee! your going to be cold in winter without those heater boxes!
Silver
Hasn't worried him the last 8 winters!!!!:o


ducky - May 5th, 2004 at 05:22 PM

Is it true that performance doesn't change it realli is just the look in the ride?????


56astro - May 5th, 2004 at 07:25 PM

Swing axled beetles have a lot lower handling threshold than IRS beetles, everything else being equal.

The inside rear wheel drops (relative to the position of the body/chassis) when cornering hard. The result is that the tyre patch on the road is the extreme outside edge of the tyre, and the centre of gravity of the car is raised and moved "outboard" of the centre of the vehicle.

The result = the vehicle flips or drastcally oversteers.


Che Castro - May 5th, 2004 at 07:40 PM

the 4 joint suspension is more predictable generally and stable, especially in the rain! Also the ball joint front end on the late beetles compared with the king & link pin of the earlier beetles adds to the handling


OZ Towdster - May 5th, 2004 at 07:44 PM

But swingers do look cool supa low!!!!!!!!


56astro - May 5th, 2004 at 09:06 PM

Quote:
Originally posted by A Westwood
But swingers do look cool supa low!!!!!!!!


Yep

Don't get alot of oil to the wheel bearings though!


bus356 - May 5th, 2004 at 09:50 PM

Is that a problem? If a swing axle bus is lowered 3 - 4 inches with a straight axle conversion will it affect the oil flow to the wheel bearings?


56astro - May 5th, 2004 at 10:01 PM

Heaps of people have done the lowering thing on swing axled cars. I've never heard of a bearing seizing due to lack of oil, but think about it.

/-o-\

with the axle tubes running UP to the wheel bearing from the tranny (from where it gets its oil) it must reduce the amount of oil getting there