Campagnolo gears
Rear Gran Sport and front Sport changer
Here is a very nicely restored 1954 Bates Volante equipped with some very tasty components. The gear changing is by courtesy of Campagnolo’s very rare early 1952 Gran Sport – the one with the drilled pulley wheels and extended cage which was only produced for a very short time. The front changer is another rare piece, a Campag Sport with fore and aft moving lever. Chainset is a 47/50 Stronglight cottered steel.
Campagnolo Paris Roubaix gear
Here
is an image of a Bianchi Paris-Roubaix complete with the much coveted
Campagnolo Paris-Roubaix gear mechanism.
For those who are not familiar with the gear it works as
follows: the top of rear drop-outs are notched and these
coincide with notches on the axle. There is no chain
tensioner at all – as the gear is changed the wheels walks
backwards and forwards to keep the chain relatively
tight. How on earth does this work I hear you
say. As you can see, a rod goes up alongside the chainstay
and has a lever at the top, not unlike a QR lever – which is
appropriate as it happens. The gear is changed as follows:–
First make sure that there is no one riding in front, or
even worse, watching from behind. Reach down to
move the lever on its first part of travel which will then release the
tension holding the wheel in the frame. The next part of the
lever travel moves the gear selection fork which can be seen astride
the top of the chain. Now pedal backwards (because the
striker is on the top of the upper chain) whilst moving the lever to
select a higher or lower gear. If you select a lower gear
then the wheel will have to ‘walk’ forward along
the notches to accommodate the larger sprocket. When this is
done move the lever back to its original position to lock the
wheel. Breathe a sigh of relief and start pedalling in
earnest again. For a higher gear, that is to a
smaller sprocket, the wheel will have to ‘walk’
backwards to take up the slack. 
You may have already guessed that I am an
armchair expert as I have
never ridden one of these gears but I suppose that goes for 99.9% of
us. The Paris-Roubaix gear was introduced in 1950. It
superseded the even more complicated Cambio Corsa which had been
available since 1946. This gear worked on exactly the same
principle as the P-R but had separate levers to release the hub and
execute the change. I think I am right in saying
that a third version of the gear was produced where the striker
operated on the lower chain and so obviated the need to pedal backwards
whilst changing. There is a cam on the gear which can be
adjusted to pre-set the chain tension after the change is made. Peter
UnderwoodDetail of the business end of
the gear showing the
serrated rear-end of the frame
serrated rear-end of the frame
This is the earlier Campagnolo Corsa gear (on a 1950 Frejus Supercorsa M) which has separate levers, one to unlock the hub and the other to move the striker arm which is on the top run of the chain. This still entails the rider pedalling backwards for the change - so not the slickest change in the world.
This gear was patented by Tullio Campagnolo in 1933.
Photo courtesy of Eric Sayliss