IRS vs Swing Axle...

17th August 2008.

There seems to be a huge amount of debate on the web forums from www.Volkszone.co.uk to theSamba.com and even to Beachbuggy.org.uk on whether the retro fitting of an IRS conversion would benefit an old swing axle designed chassis. Before I can give you my thoughts on this I would like to show you the two pictures that I have of my buggy with first the Swing Axle rear end and then the retro fitted IRS conversion.








Initially there appears not to be much difference between the two designs although the angle that the photographs where taken at are not ideal.

With this in mind I will show you the two designs situated in the air with the wheels removed so that a closer look at the two designs can be seen.

immediately you can see the difference between the two suspension types. The swing axle design places the wheels onto the ground at a slight angle causing only a partial part of the tyre to get the full weight of the vehicle in comparison the IRS suspension places the axle totally horizontal to the ground enabling all of the surface of the tyre to support the weight of the vehicle.

The main advantage of IRS here is that tyre wear is more even across the tyre. In addition because the full area of the tyre is carrying the weight of the vehicle the stability of the car is much improved when cornering and more traction is available at launch when starting from a stopped position. This all said the swing axle design also has some merits as its provides lower traction of the rear wheels making wheel spins easier and making the driver have more work to keep the rear from stepping out. These can also be seen as bad attributes but to be honest it really comes down to how you want the car to drive.

Personally I like a car to drive like its on rails as this means you can get the maximum amount of fun by traveling fast around corners.

My own IRS conversion is detailed here in six differant blogs starting from removal orf the swing axle gearbox and ending with fitting the A-Arms and spring plates. (Click on an image to goto that part please from one of the six shown below.)





Remember that the most important decision on your suspension depends on your engine performance and your driving style. With smaller wheels and tyres and narrower width there will be not so much tyre wear.

My engine rebuild has moved forward a little and it looks like I may have sourced a new crank case that has been pre bored out to 94mm. In the next episode find out if I managed to purchase it or if I am still looking for a replacement.