i just got a used belt drive sachs-huret cyclometer.... there is alittle o-ring that connects this pulley on your hub to a pulley on the counter.
on the counter there are actually two /slightly/ different sized pulley wheels side by side.
might anyone who owns or has used one of these cyclometers know if the two pulleys are calibrated for 700c vrs 27" wheels?
and... would you guess the digital readout is in km or miles?
to the second question i'll probably take it for a ride of a known distance and find out pretty soon.
but the difference in size of the pulleys are very subtle, so i figured i'd ask the internet :)
I have one on my Raleigh 3 speed. The instructions say the larger groove is for 26" (650 mm wheels). The smaller is for 27" and 28" (700 mm wheels). This info is right from the instructions written in about 6 languages. Mine has proven to be very accurate based on distances checked out by 2 different autos.