Dont go over 19-20MPH this is the LAST thing I have to worry about at my age, I do have one on the Mercian that I had at LeCirque, (BEST BRIT BIKE DALE!!!!) First off I cant read the bloody thing its too far away, Second off I cant hear the cliking!! other riders around me complain about this! Then when I did get to check the milage, I found it was counting backwards!!! it gone over I gues and was rewinding!! So back to the 20 or is it now 21st century and a new fangled computer BUT it does look good and adds a vintage touch to the bike, Cheers John Crump OldclickingonBrit, Parker, Co USA PS What does it do if you go over 19-29mph Explode? with Lucas you could never know!