Board logo

Ackerman geometry question
2cv - 29/7/10 at 07:42 PM

I'm running Corina uprights with integral steering arms and chassis has a 7ft wheelbase. Insufficient Ackerman angle causes huge amounts of scrub when on full lock.

I was wondering what uprights/steering arms folk use on short wheelbase builds such as the Mojo and Riot etc.


nitram38 - 29/7/10 at 07:58 PM

Don't you mean kingpin inclination?
Ackerman is where the wheels turn at different turning circle like a london taxi


Mark Allanson - 29/7/10 at 08:00 PM

You can alter the ackerman by moving the rack fore and aft, but track rod extensions may be required.


2cv - 29/7/10 at 08:18 PM

quote: Ackerman is where the wheels turn at different turning circle like a london taxi

Yes that's what I mean

quote: You can alter the ackerman by moving the rack fore and aft, but track rod extensions may be required.

How will this cause the inner wheel to turn more?

[Edited on 29/7/10 by 2cv]


simonwinn - 29/7/10 at 08:50 PM

My Mojo uses capri uprights and steering arms, mk2 escort was also an option. Previous versions have used sierra parts but the new J15 now uses triumph gt6 uprights and arms as per caterham, I think the riot is being re-done this way.


Madinventions - 29/7/10 at 09:21 PM

Ditto on my Mojo - Capri uprights and steering arms.
A friend of mine also has a Mojo that uses Sierra uprights and I would definitely say go for Capri!
The latest Mojo/Riots use Triumph upright similar to Caterham IIRC?

Plenty of photos in my build diary here
Ed.


2cv - 30/7/10 at 05:53 AM

Thank you all for your replies. The set on the steering arms, both Ford and Triumph are designed for longer wheelbases than the Mojo, Riot and my car so our cars will all suffer from an incorrect Ackerman angle. This may only be apparent on cars with a very good lock.

I asked the question because I wondered if anyone had successfully overcome the problem by either using custom steering arms or resetting the angle of the Ford/Triumph ones.


Dingz - 30/7/10 at 07:27 AM

quote:

and arms as per caterham,


I think this will have answered your question. It is something I had always wondered as I have a similar problem, it seems to be improved by setting the front wheels at a slight toe out. I know 2 wrongs don't make a right but it helps!

[Edited on 30/7/10 by Dingz]