Moton Spring Rates for AutoX

[Doubleup]

I am currently running 600/900 spring rates on my Moton Club Sports. I am finding I push a lot even with 315 Hoosier A8's and still get a lot of lean and the car is still a little hard to predict. I was thinking to step it up to 750/1000 as I have heard 300 pound difference is too much between front and rear and would like the car a bit stiffer. Anyone else doing auto cross or have related recommendations??

Thanks!

 

[j-rho]

You should be looking more at the ratio between the spring rates instead of the absolute rate difference. 600/900, the rears are 50% stiffer than the front. 750/1000, the rears are 33% stiffer. Besides making the car stiffer overall, it would also shift the balance towards understeer. If the car is already pushing, that is not going to help things.

Make sure your alignment is good with plenty of negative camber up front. Hard to advise on the "little hard to predict" problem but a lot of the time that sort of thing can be remedied with proper shock settings.

With the spring rate changes you're going to be in a class that allows wheel/tire changes, you could also consider going to a wider front wheel/tire. I run a 335 A6 on the front of my autocross SRT10, works great.

 

[mjorgensen Woodhouse]

I have probably tried more combinations than anyone here and can tell you that as J-Rho says you need to look at ratios first. In order to get a even wheel rate of 500 lbs. front and rear you need 600 front and 850 rear. This is what I currently run with a 315 front tire on a 12" rim. The car is loose on turn in with this setup and pretty neutral is you don't ham fist it around.

The rake in the car will also affect this and the more rake front to rear will increase corner turn in lower will cause the push you have so check and adjust from where you are now. The car can be to low also which causes nasty push.

I like a car that pushes a bit on turn it and can be driven on throttle so I will likely be trying the 650 front spring next. Also the shock adjustments will fine tune this setup. The Motons gain rebound stiffness with lower canister pressures and the opposite when pressures are higher increasing bump stiffness. This is also an area you can play with.

Tire pressures also are a factor and brand. I would need to know exactly what your current set up is entirely and the weight of the car to help you narrow it down.