Unfortunatley I cannot afford a steering wheel and pedals, I'm probably not the only one, yet I very much enjoy playing Live for Speed regardless. So far my control set up has been either:

Accelerate: Left Mouse Button
Brake: Right Mouse Button
Clutch: C
Shift Up: Scroll Up
Shift Down: Scroll Down

or

Accelerate/Brake: Axis Y
"
"
"
"

Which works fine, but sometimes when you're using the second one and you release the throttle it'll brake a bit, which affects performance. I've split the Accelerator/Brake so Mouse Y is only Accelerate but I cannot set the Brake to RMB while throttle is on the axis.

Any way to fix this or could a fix be implemented into the game?

Sounds like a good idea.
+1 from me.

Unless of course it's already implemented.