New tires pull on uneven roads

[jpinoh]

I recently changed out my original Goodyears on my 'stang 99GT and put on a set of Kumho Ecsta 712's. I read through the various reviews on TireRack.com and these seemed like a good choice for this car.

But I notice these tires are a lot more sensitive to road imperfections. Here in northern OH we have a lot of rough roads from the winters and I spend a lot time correcting the car with steering input to keep me in my lane. The standard Goodyears had little tendency this way.

I didn't change the alignment yet, and this will be changed next week when I put on the Griggs CC plates. Griggs gave me some numbers to set for street use, and a higher camber number for open tracking.

So is this wandering a function of the tire design mostly, or is there something in an alignment that dials this sensitivity out? Only one review at TireRack mentioned this sensitivity, and no other Mustang owner did, so I'm wondering if it's my car.

I have played with tire pressures a little - it's about the same at 30, 32 and 34 psi.

My current setup:
Griggs PHB/TA and SFC; new LCA's and rear coilovers going in next month
CC plates going in next week
Stock springs/shocks still - no change in rates or ride height (so this shouldn't be a case of bump steer up front).

Thanks for any insights -

--JPinOH