I noticed at the Detling kit car show that MK are doing an anti-roll bar kit for £100. I have often wondered why they are not on most 7 type cars and would appreciate feedback on their suitability, I'm building a Luego Velocity XT, should I go for one?

anti-roll bars are just one way of containing body roll. others are making you car low to the ground & reducing centre of gravity (locost), making a car with a wide track (sierra based locost), designing your suspension to give apropriate roll centred (locost), making your car light - it reduces roll moment (locost), making your suspension stiffer (locost).

ordinary cars use roll bars so that they can keep soft suspension and because tall cars are fashonable.

roll bars have a disadvantage in terms of handling. when the car is not rolling then the roll bar is untensioned. as the car rolls into a corner it loads up. if you are in an S bend, the roll bar will lighten up as you steer out of the 1st bend, will go light as the car goes through the vertical and then will load up as the car enters the 2nd bend. there is a point in the middle where the roll bar is not under tension and this can lead to a step change in the car's handling, momentarily.

real sports cars can be made to handle better (more predicatably) without them.

Why bother on a locost?
Do you get lots of roll when flying around a track?
Pat...

The rear of your Avon does

That's 'cause you were weighing one side down!

Second hand opinion:

One of the guys at the sports car club added an anti-roll bar to his commercial 7-clone (one of 14 made in Christchurch, I think, which I could remember the name).

Phil reckoned it made it heaps smoother "through the esses" at Pukekohe.
(Whatever that means).

He was pretty stoked with the change in handling.

- Greg H