Here are what settings I use along with the ini fie change I made, those settings are in another post. I run a Login echo G27 wheel so you may need to make adjustments to get the feel you like. I run a wheel lock of 5 or 5.5 in the garage just for Daytona and Talladega and 16 or 17 for all other tracks. Then under controller settings in the game, I have speed sensitivity at 10, the higher the number, the less sensitive your wheel is and vice versa. And under the mapping sensitivity for the steering in the game, I will always run 50% at the tracks, but may move it down a little to 45% - 48% for Daytona and Talladega. If you go less than 50% oon the sensitivity the center of the wheel will move right so you would be turning to the right a little to go straight. If you go higher than 50% the wheel will be more sensitive and it will move the center of the wheel to the left so you would now be turning left a little more to go straight. Also, for braking, look to see what axis your brake pedal is under, go to the sensitivity/deadzone tab at the bottom of the page, click deadzone and what ever axis your brake is on, put the deadzone at 15% - 25%. This helps with the braking so it feels a little more realistic and smoother. These are all personal settings/feels that I like so you may want to tweak them to your liking. Hopefully this will help
Here is the link for the ini file instructions and I uploaded dxtweak2 for windows 7 it is for logitech wheels, not sure that it will work with other manufacturers. I use a center setting of 6700 that will straighten the wheel so you dont have to turn right to go straight, you may need to make adjustments for your wheel.
My center setting that I use is for a 900 degree wheel. So when you run dxtweak2, click default axis settings, then apply. Now what ever your center reading is, change it to a smaller number to help straighten the wheel out. So if the center number is 500, try 400 instead, then hit apply, enter the game, and see where your at, and make necessary adjustments. But make sure you exit the game each time when changing the setting then reenter for the settings to take affect. Sorry I didnt specify how to adjust the center number for different wheels. Didnt think of it at the time
http://www.stockcarevolution.com/forum/viewtopic.php?f=2&t=513