Emails are good for those who aren't in the market for tires.

For those buying tires now or in the near future when you go and they offer Goodyear make sure you explain why you aren't interested. Even if they are cheaper.

Explaining your decision at the time of purchase may have a bigger impact. Buying tires isn't like buying a pack of gum. If people make their point GY will know sooner rather than later.