the sensor and unit need to be no further
than 60 cm apart . Also in the operation book it says designed for front wheel !

The manual says the LINE OF SIGHT distance from transmitter to base should be NO MORE THAN 60cm. I've found this to be true so I'd say that, provided you don't go over this distance, MAYBE, as you COULD mount the base on the crossbar...

It turns itself off after 15 mins of non use. But unless you clear data it will pick up where you left off when you start again

Yes when you stop cycling it stops measuring, them when you start again it adds on to what you have done before, total time distance cycled average speed etc, until you reset it.

My Knog sensor fits on my Rockshox MTB fork fine. It's a tight fit, but that's ok so that it doesn't move with the vibrations, and I've never seen an XC MTB fork that it wouldn't fit on.

The fork sensor as well as the computer itself, are fitted by a expandable rubber band that will fit almost any size fork or handle bar. I also own a mountain bike and the sensor would fit it no problems.

no it doesnt come with 2 magnets, but it does work with any magnet. i using a cheap kathmandu magnet and its working fine.

No - only one

Yes, odo for Bike 1 and Bike 2 can be set during the initial setup or after a full reset.

yes, you can program the odometer with your miles. Excuse me but my english is very bad. jajaja from Granada (spain)

You could try putting it on the rear wheel with the sensor on the chainstay. You'd have to be careful, that the distance between teh sensor and the computer didn't exceed the recomended 60cm

I reckon. The strap is really big. Obviously built to accom chunky cucpension forks. If anything it would be better on a big fork. My forks were a little to small for it (Surly LHT)

The system comes in white, black, or red as per the description.

Not the supplied magnet but I am using a cateye magnet and it works so I reckon any magnet should work.

yes, some retailers sell the replacement transmitter/sensor seperatlely