Board logo

Top ball joint
smart51 - 1/6/10 at 02:37 PM

I'm designing an ultra light weight single seater of about 220kg + driver. I want to make the top wishbones push down on an inboard damper but this will put the load on the top wishbone and so the top joint. What is the best thing to use for this top joint? Is a transit drag link up to the job as the load will be in bending for this link?

Given that I'm making a bolt on adapter for the upright to take this joint and I'm making my own wishbone, I can use almost anything. Threaded tube for the transit link is readily available for me to weld into my wishbone, which is nice and easy.


CNHSS1 - 1/6/10 at 03:12 PM

anything with a threaded shank in shear would be a no-no for me. Either use a bolt on balljoint (think Sylva Pheonix/Fury inboard top wishbone with a metro balljoint maybe??), or a nicer, neater and lighter solution would be using a spherical balljoint in a macined housing retained with a circlip as most single seaters use. This means the top wishbone is fixed, no adjustment for camber. Most single seaters get around this by using shims at the chassis mounting end, or by using rosejoints on the lower supsension arm (no damping or springing loads) to adjust the camber.
ive used the latter on my hillclimber, and bought the spherical bearing hosuings from McGill motorsports or Ralt

EDIT
its relative to loads incurred of course, but grippy tyres will ramp up loads massively

HTH
CNH

[Edited on 1/6/10 by CNHSS1]


40inches - 1/6/10 at 06:43 PM

You could use a ball joint from a SAAB, made for the job and not expensive from here


smart51 - 1/6/10 at 07:19 PM

is that Saab ball joint parallel sided? It makes the mounting half easier to build than a taper. It looks more than sturdy enough.


CNHSS1 - 1/6/10 at 07:42 PM

a variant of that SAAB balljoint is used on my TVR upper wishbone


40inches - 1/6/10 at 08:47 PM

quote:
Originally posted by smart51
is that Saab ball joint parallel sided? It makes the mounting half easier to build than a taper. It looks more than sturdy enough.


Parallel and very strong, as CNHSS1 says, used on Trevors