When the LBS mounted DH's computer on his bike they put it pretty far down on his front fork. Mine, they mounted it way at the top. For whatever reason yesterday, my numbers were all over the place. I was climbing a good size hill and it was showing 12mph and well we ALL know there was NO WAY I was doing no 12mph up this puppy, more like MAYBE 4. Anyway, I noticed that once I got on a flat, it would show like 15mph then jump around to 24 then 12....argh....it was so irritating. Do you think just re-positioning it lower on the fork where DH's will fix it. I hate to unmount it, they put it on pretty good at the LBS.