A
Andy Welch
Guest
Here's one for a Friday afternoon.
When I were a lad a racing bike had two rings up front and five sprockets at the back. Now, many
years later, the number of sprockets has risen to 9 or 10 but still only two rings up front. So why
has there been rampant inflation in sprockets but none in chainrings? Comparing a 3x7 (say 30,40,50
with 12-18) setup with a 2x10 (say 39,53 with 12-23) the former would give one more gear but
wouldn't require a narrow (fragile) chain and would need less dish (so more strength) on the rear
wheel. Surely one chainring (pluss a few mm on the BB axle) can't weigh much more than 3 sprockets
and the total difference in teeth is pretty much the same (i.e. no need for a longer rear mech). So
what am I missing here?
While I'm in pondering mood, what do you do if you have a frame with no braze on for a front mech a
seat tube diameter of 35mm and you want to use a Campagnolo triple? As far as I can tell they don't
make a triple band on mech that big.
Cheers,
Andy
When I were a lad a racing bike had two rings up front and five sprockets at the back. Now, many
years later, the number of sprockets has risen to 9 or 10 but still only two rings up front. So why
has there been rampant inflation in sprockets but none in chainrings? Comparing a 3x7 (say 30,40,50
with 12-18) setup with a 2x10 (say 39,53 with 12-23) the former would give one more gear but
wouldn't require a narrow (fragile) chain and would need less dish (so more strength) on the rear
wheel. Surely one chainring (pluss a few mm on the BB axle) can't weigh much more than 3 sprockets
and the total difference in teeth is pretty much the same (i.e. no need for a longer rear mech). So
what am I missing here?
While I'm in pondering mood, what do you do if you have a frame with no braze on for a front mech a
seat tube diameter of 35mm and you want to use a Campagnolo triple? As far as I can tell they don't
make a triple band on mech that big.
Cheers,
Andy