OK a real hard one for you all :duh

What does IRS stand for, what does it mean and to which model VW's does it apply?
Just to enlighten the uneducated people like myself.
Thanks,

Independant Rear Suspension, as compared to live axle (solid axle)

from my way of thinking all VW's have IRS, but the type of IRS is different. When most people refer to IRS in VW terms there refer the later model design with inner arms compared to the older IRS design which used the axles (swing axle) as the inner link.

the newer IRS design lessens the rear wheel chamber changes as the suspension moves. In essense the Swing axle system has the major pivot point about the sides of the gear box (it also pivots about the torsion tubes) and as such swings in a arc about this point (left to right plane), while a later IRS pivots about the rear torsion tube (both arms) and in a for aft plane.

hope that helps. but iam sure someone will correct me.......

[Edited on 24-6-2005 by BiX]

that was no fun! right 1st go & more bigger words than I would have used

Yeah the IRS term is a misnomer. Some people call it "4 joint suspension" because of the two pairs of CV joints. another problem with it is that the toe also changes as it goes through the arc.

Thanks Bix, that was the whole point to the question (sorry for the hidden agenda).
When and where in the motoring world is IRS used. Independent suspension is independent suspension no matter which way you look at it, why narrow it down to front or rear? It seems a wasted term.

If you want to get specific, refer to the actual type of independent suspension, like swing axle, semi-trailing arm, wish bone, strut etc.

I guess I was wondering if the "R" meant something other than rear??

Anyway, it's an hour closer to beer o'clock now

http://en.wikipedia.org/wiki/Independent_rear_suspension 
(From link above)
An Independent Suspension is an automobile suspension system that allows the wheels on an axle to move independent of each other. This is contrasted with a live axle or deDion system in which they are linked.
Most modern vehicles have independent suspensions on the front wheels at least. An Independent Rear Suspension (IRS), as the name implies, has the rear wheels independently sprung. A fully-independent suspension has an independent suspension on all wheels.
Early independent systems used swing axles, but modern systems have use Chapman or MacPherson struts, trailing arms, multiple links, or wishbones.
Another key difference which sets an independent layout from the conventional live axle is that, for driven wheels, the differential unit does not form part of the unsprung elements of the suspension system. Instead it is either bolted directly to the vehicle's chassis, or more commonly to a sub frame.
The relative movement between the wheels and the differential is achieved through the use of swinging drive shafts connected via universal (U) joints, analogous to the Constant Velocity (CV) joints used in front wheel drive vehicles.

A semi-trailing arm suspension is an independent rear suspension system for automobiles in which each wheel hub is located only by a large, roughly triangular arm that pivots at two points. Viewed from the top, the line formed by the two pivots is somewhere between parallel and perpendicular to the car's longitudinal axis; it is generally parallel to the ground.

One of my pet hates is people also calling strut front suspension and A arm front suspension Macpherson Strut Suspension. Macpherson Strut front suspension uses the front sway bar as another control arm. in a mac strut system there is a strut, control arm and the sway bar locates the 2 above components longatudially (spelling?), while in most cases with modern cars, the longatudal control of the system is done by a seperate arm or a wishbone, which is sperate to the swaybay.

Eg if you took the sway bar out a Mac strut car, it would mean the car woud not be able to be used..... sorry just some of my little pet hates form terms for items........

all finished........

Independant rear suspension or IRS was a valid term in both marketing & description up until relatively recently because most cars post WW11, especially outside Europe, had independant front suspension only

Just a small snippet of BS:
John Muir, author of the "Idiot's guide" refers to IRS (as defined so well above) as double jointed axles.
I rate the IRS system the only choice for anyone wanting to hot up their VW after a nasty experience of "swing axle tuck" once...basically the back outside wheel wants to try and go under the car when turning to the opposite direction at speed. Pretty scary stuff, but anyway...
Cheers,
Toby

Should be called semi-trailing arm really... IRS and double jointed axles are just general brandings.. doesnt actually tell you what design it uses.

Hi

I wrote too a well known motoring journalist once when he said the comondore was the 1st Aussie ute with IRS, I pointed out the splity utes to him. They did put a retraction in.

Steve

Nicely put steve I like your play on COMONdore but guys and gals (sorry) lets not forget that Holden put out radial tuned suspension

Now wasnt that a great break through

Toyota now uses the term IFS as well for their Independant Front Suspension like on their 100 Series Cruisers....talk to any hardcore 4wdriver tho and they'll tell you IFS is for girls.....

My VR Commodore has a flashy looking badge with IRS on it - but it's still a Commodore, It also says ABS - but the front driver sensor tells the diagnostic that one rim is 10ks slower than the others, and despite swapping the entire stub axle and the sensor cable, it's still farked - making it just and IRS and not ABS IRS as the cheap plastic badge says. Still, the brakes now remind me of a bug with drums all round that aint been adjusted for 2 years.

Anyway - IRS, In the UK - Inland Revenue Service.