The Fells offers a ton of variety in its biking, but to really capture it, you need to do the 8-mile mountain bike loop that goes all the way around the reservation. This has lots of gravely fire road, rocky and rooted singletrack, some tough climbs, a few small wooden bridges... all kinds of stuff. All in all, a really good ride. Next time you go back after you've done the loop, try out some of the random single track trails you can find!
From North: take 93 South to exit 35. At the stop sign, take a left under the hightway. At the next stop sign take a right, and at the first set of lights (rt28) take a right for Sheepfold enterance. <br />From South: take 93 North to exit 33(RT28N) for Sheepfold or proceed halfway around rotary and take South Border Road for Bellevue Pond.
http://www.singletracks.com/item.php?c=1&i=1424