HI,
I've got an 06 A6 base coupe with 275 35 19 and 245 45 18 snow tires on OEM 08 c6 wheels. The 245 45's and 275 35's were sooo close in tire diameter I thought they would be fine. Well, active handling kicks in at 60mph and stays on if you maintain that speed. I have to turn off AH and TC just to drive the car over 60 mph. Is that 5mm difference in front tire aspect ratio really that much of a problem that it's causing the AH to engage? I could put the stock summer wheels and tires back on to recheck the AH system but thought I'd check here before dragging the floor jack out.

PS:I know, snow & C6= bad combination. I do plan on getting a second car, but in a year or so. Unfortunately too many unanticipated things needed on the house this fall. I'm in a wheelchair from an industrial accident so buying a beater isn't feasible for the winter(chance of being stranded) and just the cost to modify a car with hand controls can run 1000.00 or more.

I did drive a high stall converter'd 3:73 geared c4 corvette thru 5 Wisconsin winters on summer tires in the 90's and never had any issues. Well, at least until I put 335 Michelin Pilots on, then it wasn't good in the snow anymore.lol I also drove a lightly modded LS1 Z28 thru 8 winters.

 

There is over an inch difference in stock F/R tire diameters.

If you don't maintain that relationship, or at least fairly close, you will encounter the problems you're having now.

Of course this assumes you don't have some other AH issue. Has the AH TSB been performed on your car?

 

Thanks for the reply. Wow, I was just on tire rack. There's a 1.2" difference on the stock tires! Well that explains the difference. I didn't realize the difference was that big between the fronts and rears. I guess I will be ordering new front tires. There is .2" difference right now between the front and rear snows. I just bought the car in late September so I'm not sure if the AH tsb/recall was done.

 

If you haven't had the TSB addressed and the system acts up, you'll get a "Service AH" warning in the DIC.

If you get this warning you want to have it fixed ASAP. The usual cure involves correcting a faulty connector in the steering column.

Fairly easy and inexpensive if your dealer won't do it for free.

 

You went UP in diameter on the front tires and DOWN in diameter on the rear. You need much smaller fronts, maybe 225/40/18.

 

Are you sure AH is activating or is it just traction control. AH applies the brakes to a single wheel depending on whether or not the car is not turning fast enough in the direction the driver is turning the steering wheel. It doesn't use wheel speeds in determining when to activate.

Bill

 

Since this is a recent acquisition, I'd caution you to re-read the stats on clearance of a C4 vs. a C6. Before the snow flies to an appreciable extent or you could get stranded by high-crowning or snow pack. jmo