A customised and revitalised four year old Trek District
After 5,000 miles plus on the road, the 2010 model of the Trek District Single Speed carbon may need a replacement belt. If you get in touch with the belt manufacturer Gates, it can point you to a local dealer. It is tempting to upgrade the original CDC system to the newer CDX system, which is supposed to be stronger, lighter and more reliable. Crucially, you can also speed the bike up by 10% by installing a 20 tooth rear sprocket, in place of the original 22 tooth sprocket. Note, you can't change the size of the front sprocket (which has 55 teeth) because there isn't enough clearance.
The CDX system in a 55/20 configuration - 10% quicker than the original gearing on the flat
Although a new belt should cost you about £80, replacing the belt and the sprockets could be £250. But the sprockets will need replacing eventually, anyway. And, if you have the time and the inclination, you can install the new parts yourself. There is a very helpful series of videos by Jeffrey Kittredge here
. But note it can be much tougher than it appears in the video to prise the lock ring off the rear wheel. You may need to leave the wheel on the bike and turn the pedals, while holding the lock ring in place with an adjustable hook wrench (19-51mm 3/4-2"). With some oil and muscle power, this should do the job. Equipped with the new belt and the higher gear ratio, the Trek District rolls along beautifully on the flat, but steepish hills will have you out of your seat and breathing hard.
As referenced in an earlier post
, you should also consider replacing the original tyres with something much tougher, such as Continental GatorSkins. For predominantly urban riding, you may also want to replace the wide handlebars with a short, straight bar, while swapping out the leather grips, which are prone to unravelling, for something hardier. And it also makes sense to add toe straps to the pedals to keep your feet in the right riding position.