Steering exponential
 

I'm after a perfectly linear feel to the steering in my AE B6.

I've always used -ve expo on my KO Propo EX-10, normally around -15%. I'm questioning if this is enough.

What puzzles me is reading/hearing people say 'I don't use expo because I like the linear feel'.

The servos we use in cars do not provide a linear lateral output. The servo moves through an arc, mechanically the movement around centre is greater at given input than at the extremity of travel. Therefore 0% expo on a transmitter equals positive mechanical expo.

What complicates things in a buggy is it's not just the servo horn that moves in an arc, so do the crank and hubs.

Am I right in thinking if I achieve a perfectly linear lateral movement for the horn, this will effectively translate to linear movement through the rest of the system?

-46% expo seems to be spot on for the horn.

I usually run at least enough exponential curve on the steering to make up for the positive mechanical expo you describe. Do what works for you!

You could use a setup station to measure the wheel lock versus transmitter wheel motion if you truly wanted to get as close as possible to a linear response. You'll never get it perfect, of course, because there's no guarantee the transmitter curve will match all of the non-linearities created by the linkages, and then of course there's Ackerman, so which wheel should you measure?

Having in mind that 1:1 cars implicitly have mechanical steering expo and it does not seem to be a big deal, I would tend to say having 0% tx expo would be most like the steering feel in 1:1 cars. There is no such thing like 100% linear steering as far as rotating parts are involved, which is always in conventional car steering.

Howard, this is 100% on-point. around -15-20, depending on servo throw will actually make up for mechanical positive expo for linear steering. I go for around -30 for a easy to drive, less twitchy car with the sharp turn-in when you need it.

Buddies who have driven my cars always comment it is easy to drive and "dialed" - sometimes i can't even drive theirs it is so twitchy / sensitive.