I know that there are front/rear specific MTB tires.<br><br>
Mine don't match on The Tick, but it's more of a fashion statment than a performance issue.<br><br><img alt="" src="http://farm3.static.flickr.com/2289/2245004195_99d5e10f0e.jpg" style="border:0px solid;">
Pure vanity for road tires, as far as I know. For MTB tires, some of the high end tires DO have front and rear specific tires as well as directional tires. I have a set of directional ones on one of my MTB bikes.
Not that important to me as I have a Shimano front wheel and a DT Swiss rear wheel. The bike came with Shimano wheels and when I got a PowerTap, they built the PT hub on a DT Swiss wheel. Everyone, including the LBS, told me it wasn't worth the money to buy a matching front wheel.<br><br>