I got some antiroll bars made by Alan gow a few years ago but have only fitted the front one as i still building car .Contacting Alan was very difficult and he did not seem keen to make them i have since found they are not the correct diameter they should be 18mm but the ones i have are 19mm front and 20mm rear .Reading the above posts makes me think the front will be ok but the rear will be to stiff as most i have seen run them on the softest setting as in Svens picture with 18mm bar this makes me this is also to stiff so as i have all ready made the drop links and have made solid ally d bushes clamps that screw from inside so there are no visible fixings because the first thing you see when you look through back window is roll bar if fitted so i need to get a replacement softer bar.I have contacted i company who said they can bend one in 16mm bar i am going to send them a drawing of the shape of the 20mm bar so they can give me a price to copy in 16mm then i will make the plates with the holes in and get then welded on.I hope this will give me a bar with a good usable range of adjustment and from what i have read above to soft on rear is much better than to hard .Let me know if anyone else is interested in having one made ?

Changing from 18mm to 16mm will decrease the ARB stiffness by 40%. To replicate the "full soft" setting of the 18mm bar, you would have to move the attachment point 20% of the way back to the axis of the 16mm bar.

You could try the 20mm bar (52% stiffer than 18mm) and perhaps soften the springs if it has too much oversteer.

If you ever consider fitting the Z Cars rear suspension you might need the 20mm bar so hang on to it.

I'd be interested to know the cost of these. I'm still planning on getting Dave Gallop to make my front but the rear is hopefully simple enough to not need Dave G's specialist skills, although I will take his advice on the right stiffness.

Spider thankyou for figures on the different roll bars.I am now thinking i maybe better off replacing the 20mm rear with 18mm as gtm specified because my front is 19mm that also should be 18mm so fitting 18mm rear and keeping the 19mm on front would be close to gtm recommended spec but would only have expense of one new one but the one that is most important to get right when building car is front as its hardest to change

I fitted Alan got was arb's but can't remember the thicknesses but could find out when I get the car back from storage once my extension is done on my house (bigger garage)
I do have a z cars set up but I think mine handles really well with what I got

Must apologise, I was thinking you had a 19mm rear bar - should be 20. I have altered the post.

Have now got price from tube bender to supply and bend 16mm bar £75 delivered which will then need the plates with the holes in welding on.The e mail he sent said he can only do 16mm not 18mm but gave no reason why.I will send him another message to see why he cannot do 18mm.

Mark try Phil Boffey at BMS Engineering in Coventry he has CNC tube bending he does my 1.0 inch AR bars does a lot of Motorsport work
Ian

tube bender said he only has tooling to do 16mm and google seems to say lotus elise only has 19mm front so i have decided to go for soft option and order 16mm rear

I don't have any roll bars for my Libra, so I would be interested if someone is getting some made up. I wouldn't really know where to start! Please message me if you are getting some made, I would happily come in on it.