Computer to use with a trainer?

[OakLeaf]

Is it wireless or wired?

If it's wired, before you go hauling the bike around, just eyeball the wire and see if it's long enough to reach your chainstay. Odds are it wouldn't be ... but if it looks like it would reach, then it's probably a good idea to let the LBS show you how to route the wire so it'll stay out of the way.

If it's wireless, you can test it yourself. Take the computer head out of its mount and hold it at about the same distance from the front wheel sensor (or a little farther, just to be sure), as the mounting bracket is from your chainstay. Then spin the front wheel and see if the head picks up.

If so, use a pair of side cutters to nip the zip-ties off, unscrew the wheel sensor from the wheel, then zip-tie the receiver onto the left chainstay and put the magnet on the rear wheel. Most computers recommend 5 mm clearance between magnet and pickup for the best reception. Don't forget to use those side cutters to clip off the protruding ends of the zip-ties once they're tight. Probably best to use a dab of Loc-Tite on the magnet screw, since IME they're prone to coming loose.