irs vs trailing arms,etc

What is the feeling of owners on the virtue of going with the non- irs suspension on a speedster? Who has the Irs? Beck, Jps or Intermeccannica

Beck is swing arm only, while JPS offers both. I believe IM is IRS only.

It would be interesting to hear of owners who've driven both and know what the experience of driving non-irs cars is like (?).How does your Beck handle with a non irs suspension, Lane ?

We added a camber compensator when it was built, so I've never driven it without one. Even without a front sway bar it corners flat and sticks like a go-cart. And it rides much better than such a small, light car normally does. Compaired to my old MG Midget, the Speedster rides like a Cadillac. I have no complaints at all.

I don't know if Henry at IM is building any swing cars or not. He probably can and will do anything if there is enough money. One significant difference of IM IRS cars is the repositioning of the engine/trans. 3 inches forward. It makes a difference in weight distribution and cleans up a little of the oversteer problem of original speedys and other replicas.

I have owned 2 earlier IM's. One was with swing arms and the other was IRS. Of the 2 cars the IRS was by far the better handling or perhaps more accurately said, more forgiving, to a point. However, when pushed past the limit the IRS car would swap ends instantaly and there was no saving it. It was going to do at least a 180 and sometimes a 360 degree snap...It had a front sway bar on it when I got it and pretty much stock rear setup.....

I think the biggest problem on the swing axle car was tucking the wheel under and jacking up the rear end.....pretty much known issues with swing axles.

I choose the IRS car for the big engine and drove it hard, but after the first 360 I was never quite so fast through the corners again...

The camber compensator will eliminate the tuck problem - at a slight cost in ride comfort, I imagine. I haven't pushed mine hard enough yet to get the rear to let go. It seems pretty sticky so far. I've got 185/60-15 Goodyear Eagle RS-As that hang on pretty well.

Your topic subject is a little mixed up, and I assume you're asking about the differnces between IRS (so-called Independent Rear Suspension) and a "Swing Arm" rear end, so here goes:

Either swing arm or IRS will spin the ass-end around on you, depending on how hard it's pushed AND the size (both diameter and width) of the rear tires. Tires make far more difference than most people realize with these cars.

To be honest, it was a LOT easier to spin the rear of my wife's Austin Healey 3000 MKII around than my Speedster, because it had these really skinny tires on it versus the BIG tires all around on my particular Speedster (205X16 front/225X16 rear).

IRS cars tend to corner flatter than swing arm cars, with far less likelyhood of lifting the back, inside, tire off of the pavement in hard cornering. Swing arm cars tend to tuck the rear, inside, wheel under on very hard cornering (you un-weight the rear inside corner, lifting the body there and allowing the torsion bars (springs) to push that wheel down as far as possible - in doing so, it "swings" under a bit as it unweights, due to the sspension geometry back there).

IRS cars only allow the rear wheel to travel straight up and down, so there is no "Tucking" under of the rear wheels. This is a good thing, as it does not allow the unweighted portion of the car to become as unstable, allowing the driver to maintain control under harder cornering techniques. The inside, rear, corner still unweights, but the wheel does not tuck under. You still have to worry a bit about tire sidewall curl under, but no where near as much as with a swing arm car.

There's a terrific article about making a IRS VW Sedan handle better, so I will forego further discussion and simply piint you there:

http://www.aircooled.net/gnrlsite/resource/articles/handling.htm

Hope this helps....

Oh, and apart from the "nostalgia thing" about a swing-arm Speedster being closer to the original 356 (which it is), there are a number of good reasons why VW switched from Swing Arm to IRS in 1969, most of which related to improved handling.

All good points; I haven't had the chance to drive an IRS equipped Speedster replica but with regular Bugs & Karmann Ghias there's a definite difference in how the cars corner; IRS cars stick to the road better. I guess the same applies to our replicas.

Thank you all for the experienced insights and straight talk. Very helpful. I suppose an irs is a little harder to find (for pan based cars) as that was nearing the end of Bug/Ghia manufacturing(?)

P.S. I Love this Sight!

You're right; IRS cars started in 1969 so there's less numbers out there. That's why you pay extra for an IRS equiped build.

If it's worth anything, I have a really super-duper easy suggestion for flattening out the cornering in a swing-axle car. I've welded a nut to each suspension piece below the spring blades. When the axle tries to drop below the new stopper, it can't. The blade rests on the nut, resulting in a flatter turn.
Simple, but effective.

Hey!!! Corey, Sounds just like the same solution as mpne , except steel verses rubber....