Absolutely you can tell your shop about this site!
Many of these issues have been discussed here on meta, although not all of them conclusively.
Part of the problem in explaining these sites to people is that Stack Exchange is not a forum, it's a Q&A site. The differences can be subtle. For that, have a look at this: One short paragraph that describes this siteOne short paragraph that describes this site
We've discussed how to maintain interest over the winterhow to maintain interest over the winter.
Here are some flyers you can useflyers you can use to promote the site. We'll have some with the new design shortly. (I've been putting that off, will get to it ASAP.)
Part of the problem is that we need to explain to bike shops: What's in it for them? Why should they help promote this site? People who sell and repair bikes in general do it because they love bikes and like talking to people about them. What would it add to the equation for them to promote this site?