Anyone know why wishbones are suposed to be different lengths?ive tried it on with kiddies geometry set and can see no difference between equal and
not,answers on a £5 note please
The reason for unequal length wb's is if they were the same length the track (in this case the distance between the tyres where they touch the road)
would change as the wheels go up and down. Also with the top 'bone shorter than the bottom as the wheel moves up (outside wheel on hard cornering) so
the negative camber increases and improves grip.
John
thanks for that,i used to have a book explaining all that but its gone now,is there a formula for working out difference in lengths and top bone angle
etc? 
quote:
thanks for that,i used to have a book explaining all that but its gone now,is there a formula for working out difference in lengths and top bone angle etc?
Allan Staniforths books, Competition Car Suspension and Race and Rally Car Source Book deal with the complexities of suspension design in an easy to
understand way. Use the books link on this page to get hold of these if you want to have a go at designing your own suspensuion, or are just
interested in what suspesnion design is all about.The books also show how you can model the suspension using an easy to construct model.
In short, the lengths and angles of the wishbones control the manner in which a number of things behave, these being the camber angle of the wheels in
cornering as body roll occurs, the camber angle of the wheels in acclerating and braking (due to the chassis pitching) and the camber angle of a whel
when it goes over a bump or dip in the road, plus the previously stated change in track width, and also very importantly the roll centre of the
suspension. The roll centre is the point about which the vehicle rolls, and you need to get the height of this right if you dont want your vehicle to
jack up like the chevy corvair did, and you need to stop it moving about if you want the vehicle to settle into a corner quickly and behave in a
predictale manner
That wasn't really very short was it?
There's a good photo on page 124 of the new Tiger book.
It shows a Tiger cornering with some visible (though small) body roll, yet the outside front wheel (the one that matters ) is nice and square to the
track.
Good front suspension in action.
Thanks for the input peeps,i did have the book and very good it was too,but it went walkies and i cant get a new one,so there you go.
Also with equal length wishbones the trackwidth changes more. This causes the car to slow down due to higher rolling resistance, but i reckon with most unequal set-ups there is some of this present.