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Fri Mar 25, 2005 1:45 pm

what are the benefits/drawbacks of IRS over Swing axle on beetles? is it easy to convert? what does IRS mean?

Fri Mar 25, 2005 2:33 pm

Actually IRS is a misnomer, it means independant rear suspension, because it has an articulation at the transmission and at the wheel. However the swing axle is also independent in that both wheels move up and down independent of the other. Although in the swing axle the articulation is only at the transmission.

Some people swear that the swing axle is an stronger unit. Unless you are going to drag race or so either transmissio will provide good service. An advantage for the IRS is that if you lower the back you do not get the extreme angles on the tires you get with a swing axle (although somepeople like that look).

I have read that doing the conversion can be expensive but perhaps someone else can comment on that.

Fri Mar 25, 2005 3:37 pm

The biggest benefit of IRS is better handing. The tires move straight up and down when you go over bumps. The rear ends on swingaxles will tuck in and out as you go over bumps or around curves. If you haven't driven a swingaxle before and try to drive around a sharp curve at too high a speed, beware, because they can be very squirrelly. Unless you add a camber compensator, and even then an IRS still handles better.

Swingaxles are preferred by a lot of offroaders because of the solid axle tubes that protects the axle, and the side gear/fulcrum plate setup inside the tranny holds up better than CV joints (and having no rotating axle boots to get ripped up is a plus as well). Plus your rear wheel bearings are lubricated by the transmission fluid and rarely give any trouble. It's easier to beat the hell out of a swingaxle than it is an IRS. The real hard-core offroaders will adapt an old split Bus rear end to fit their bugs, which have a reduction gearbox on each outer end. This raises the car quite a bit in back, and gives a much different and lower torque characteristic to the car.

But.... IRS's aren't bad either, and they handle a lot better, plus, as was mentioned, it's easier to raise or lower the rear end on than on a swingaxle.

andy

Fri Mar 25, 2005 10:16 pm

thanks miguel and andy that clears my confusion... so IRS has 2 CV joint boots on each side right.... one from the tranny end and one from wheel end.. i just bought a car which has IRS so was wondering if i should install that rear suspension system on my 69 which has the Fuchs 225 16 at the back...though no problems but i hate that positive camber look when i reverse the car....

Sat Mar 26, 2005 9:31 am

It's not much of an option to switch from swingaxle to IRS, or vice versa. The rear ends of the cars are set up completely different between the two. It would not be a "bolt-on" modification by any means.

andy

Sat Mar 26, 2005 11:57 pm

We have a swing axle on our sandrail and IRS on my convertible. Love IRS, hate the swing. There, the late Beetle opinion given so all is cool with the forum police. Now, Asad, you have a '94 Patrol? I had a '69 Patrol I bought from my in-laws and completely restored it. Like a fool, I sold it. Amazing vehicle. Held roughly 2 gallons of oil, had adjustible ball joints, crank start if needed, waterproof ignition (could go through 3' of water according to the owner's manual, etc., etc.). If you ahve a pic of you '94, please PM me. Just curious as Nissan quit importing them in '69 due to their pursuit of the sports car and, perhaps, safety issues. VW's rule!

Sun Mar 27, 2005 1:14 am

If you are on a budget , the swing axle will last longer and require less maintenance. YOu can change from IRS to the swing axle setup with just a bolt in swap, but going from Swing to IRS, requires more parts and some detailed welding.

A friend of mine recently changed his IRS rear suspension from IRS over to swing axle and it was pretty easy to just change out parts. But, he also does lots of drag racing on the street and wanted the stronger trans and axles. He has a $1,400 custom built swing axle tranny in his car and set up the rear suspension with zero camber, with him sitting in the car. He used custom made coil over shocks on the rear suspension and eliminated the torsion bars, from doing anything, but they are still there.

---George4888