Join Date: Sep 2004
Location: Southern California
Bikes: 2013 KHS Flite 747
I hate to do this, but...
No matter how long you pedal, your distance on a trainer is zero.
Seriously, for less than the price of a front wheel roller, you could buy another cyclocomputer (cheapest one) and use it on the back wheel. You could leave the magnet on the bike, but make the sensor and computer part of your indoor trainer. Just velcro, tape or rubber band the sensor and computer on when you need it.