Printable Version | Subscribe | Add to Favourites
New Topic New Poll New Reply
Author: Subject: Top wishbone
madteg

posted on 21/1/17 at 10:53 PM Reply With Quote
Top wishbone

I am trying to sort out my wishbones, what is the reason the top wishbone is shorter than the bottom one. I can find camber,caster, tow in and out anti roll bar and Tyre scrub but nothing on wishbones on internet. Help please
View User's Profile E-Mail User View All Posts By User U2U Member
MadMaxx

posted on 21/1/17 at 11:11 PM Reply With Quote
To avoid or at least keep low the variation of camber angle in external wheel during rolling of chassis in a curve





My re-building diary:

http://www.llcc.it/YetAnotherForum.NET/default.aspx?g=posts&t=13448

View User's Profile View All Posts By User U2U Member
motivforz

posted on 22/1/17 at 08:47 AM Reply With Quote
It helps to think of an extreme example. Imagine two parallel wishbones of the same length, directly above each other. As you move the wheel upwards, the angle stats the same.

Now imagine the top wishbone is only 50mm long. If the wheel moves up by 50mm, the bottom wishbone moves up and slightly in (following the arc of the circle). The upper wishbone moves up by 50mm, but because that's the length (or radius of a circle) it also moves in by 50mm. This relative movement of the upper in by 50mm, whilst the lower moves in only a little bit, adds some positive camber.

This is known as camber gain(despite it being negative), and is desirable because as the car rolls the outside tyre tends to lose camber (goes positive) and therefore reduce grip. Camber gain counteracts that.

It is also a bad thing. Think about a braking phase. You don't want any camber change because there's no roll in the car, but the front axle dives down, causing the motion which generates extra camber, reducing the contact patch between the tyre and the road.

It's called an SLA (short-long arm) geometry. Hope that helps a bit!

View User's Profile View All Posts By User U2U Member
MattD

posted on 23/1/17 at 12:49 PM Reply With Quote
Have a play with this & you'll what's being explained above...

http://www.racingaspirations.com/apps/suspension-geometry-calculator/

View User's Profile View All Posts By User U2U Member

New Topic New Poll New Reply


go to top






Website design and SEO by Studio Montage

All content © 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [© 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.