Caster

[Minicooper]

I have built the chassis as per the book, placed the wishbone mounts as they should be and used offset mushrooms in the sierra uprights.

What should the caster measurement should I end up with. I want this measurement to see how accurately or not I have made the chassis. If necessary I can move the upper wishbone mounts to make it better

Cheers
David

[robo]

There was a thread on caster or the lack of it, it was noticed that the 2wd sierra upright had built in negative trail ( the wheel spindle is forward of the upper and lower swivel positions) . Its this that causes some lack of self centering in the front set up. The off set mushrooms dial out some of it but moving the top mounts back would probably give you better results. The 4x4 sierra uprights have no negative trail.

Bob

[Minicooper]

Thanks Bob,
I still would like to know what the caster measurement should be, I think I will just work it out from the book drawings seems this is the only way to find out the measurement for sure

Cheers
David

[robo]

The general consensus is caster should be between 5 and 7 degrees. But you need to take off the 10mm of neg trail in the upright or you wont be getting that in real terms. The upright. http://www.super7thheaven.co.uk/Sierra_Upright

I always thought it would have been better to have a fully adjustable top wishbone so there was the scope to dial in what you need.

http://trikingsportscars.co.uk/wp-content/uploads/2012/10/trikingfullyadjustablewishbones1.jpg

Bob

[AshG]

mine is spot on 6.3deg both sides using offset mushrooms. i faced the offset hole forwards. if you line the centre of the hole up with the line in the front of the casting it should be absolutely spot on if the chassis is built correctly.

[Minicooper]

Thanks everyone, I will have a measure and see how close I am

Cheers
David