Front beam tilt angle

[Sam101]

Evening gents ,  it if a weird one but when I stripped the donor beetle there were a couple of Ali cup shims clamped on the top or bottom beam , I can remember .

But this leads me to a question on my rail build , the original setup the top beam would of lent rearward a probably 5 degree or more .

I know the original set up would of had a slightly higher rear end but I want to go for a more level chassis / ride .

But having scanned the net there have been mentions of tilting beams backwards abs forward and the technical reasons . But for me I need laymen terms , almost to the point of drawing with colouring crayons included .

If anyone could shed some light onto the subject it would be muchly appreciated .

Cheers Sam

[Manxdavid]

The shims will have under the bottom axle tube to increase the positive caster angle, responsible mainly for the self centering action of the steering. Standard caster angle can be decreased by big tyres on the back or lowering the front so one or two sets of shims will counteract this.

https://suspensionsecrets.co.uk/caster/#:~:text=Caster%20is%20the%20measure%20of,vertical%20is%20the%20caster%20angle.

[Sam101]

Thanks for the reply , it does make sense , so won’t my tail having been higher at the rear and the frame designed to allow for the camber , if I am lowering the rear to get a more level ride , does that mean that I need to shim the top tube to maintain the the same / correct angle , otherwise I will end up with a ten plus degree of tilt back , which i assume would be detrimental to the steering control ?

[snoopy]

excessive castor angle will make the steering heavier to turn as it will want to straighten more when going forwards.
Best build with no shims and see how it drives as fugitives came in offroad and road use versions and I do not know if Alan Arnold and the crew at UVA changed the front frame angle but I doubt it.

you can fit shims after if needs be.

[Paul1953]

Agree with Keith here...  Castor angle was set for a beetle and it`s associated weight and suspension/steering foibles. Start simple and see what you have.

[Sam101]

I will keep it as is then until the end , it is just that I am going to be dropping the ride height at the rear to a more level ride which would give it a mountain of tilt rearwards which would make it a pig to adjust later once sterring colum is finish fitted . Ill keep it as it is and see how it goes .

Once again cheers for the advice