Forks have a huge affect on the feel. There are too many brands to name, but I assume your not looking at forks that are priced at $1500+... RST probably make more forks then any other brands, and mass market them on Kmart bikes, as they are only low end shocks. Biggest manufactures of decent forks would be Fox and Rock Shox.

When you step up the price of a fork, you dont just get a variety of travel options, but also rebound, motion control, lockout, preload adjustment etc, as well as significant weight decreases, and quality parts.


In your examples between the two Treks, you will notice a huge difference between the 80mm and 100mm forks you suggested above, just in the travel. As they are both low end forks thats the only difference you will notice.

If you're tossing up between the Trek 3900 and the "higher model", there is a lot more to the feel of the bike then the fork. The components on Trek bikes increase in quality as you pay more. So it is worth spending a bit extra, as the 3900 is one up from the base model.

Hope this helps