I am building a mcsorley +442 but with rear IRS using sierra diff and half shafts.Can anybody tell me how much toe-in the rear irs setup should have.I would prefer answers from users with proven knowledge as i am setting the irs myself with the aid of the usual bibles.

Help anyone ?????????????????????

I haven't set up a locost yet, but others I have experience with. One quick consideration would the how rigid the toe link is, and if it is to be mounted front or rear of the axle line. Typically, people have set the wear with zero or a slight toe in (approx 1/16). But if the link is front mounted and flexes, it will tend to toe out on accel and vice versa (albeit less so on braking). Cheers!

The rear of the 60s Lotus Elan ran with 1/16" toe in. Although strut suspension the lower wishbone controled the toe and was very similar tp most Locost IRS setups.

You want to avoid toe out (unstable oversteer). So the normal method is to set up with a little toe in so any suspension flex under acceleration does not cause toe out.

I am using a spherically jointed rear which I hope is very stiff.

I set my car up with parrell strings down the side of the car and my toe is such that the front of the rim is 1mm further in than the rear. My car is very stable under acceleration

If the bushes are rubber I would set up with a lot more static toe.

Try bolting a long bar to your hub and see how much it flexes!

John