Track racers obsess about gear ratios. While they are important they are
not as important as you might think. Some very good regional track racers
have only had a single gear on their bike that they have never changed.
Chainrings are more important than cogs. Changing your chainring 1 tooth
will change your gear about 2 inches while changing your cog will change it
about 6 inches. In the road changing the cog 1 tooth is not a big deal but
on the track that one tooth difference will often be the difference between
the biggest and smallest gear you ever race in. A full gear set can be made
with 3 sequential rings and 3-4 sequential cogs. This will allow you to
make roughly 2 inch changes from a low training gear to the biggest gear you
need. For racing at Alpenrose you want gears ranging from the mid 80s to
the mid 90s. Gear inches are calculated by dividing the number of teeth on
the ring by the teeth on the cog and multiplying by the nominal 27 inch
diameter of the wheel. The most common track rings are 46 and 48. A 46/14
will give you a 89 and a 48/15 will be 86. That is a good place to start at
Alpenrose. 46-47-48 rings and 13-14-15-16 cogs will give you gears 78-100.
I think cogs should be made of steel. The marginal weight savings of an
alloy cog is way more than offset by the lack of durability. Most cogs
screw on. Miche developed a splined system with a screw on carrier. The
spline system has advantages but only if you have splined cogs too otherwise
you just have a more complex cog changing system.
Cheap stamped cogs can strip the threads on your hub so they should be
avoided. Beyond that machined cogs are fairly equivalent. Even some of the
expensive cogs can make a lot of chain noise.
If I were you I would get a splined cog that allows you to leave the carrier
on your hub and yields a gear in the upper 80s. Race on that one. Get one
a 1 tooth larger cog and train on that one.
Mike Murray
-----Original Message-----
From: obra-bounces@list.obra.org [mailto:obra-bounces@list.obra.org] On
Behalf Of Brandon Sequoia
Sent: Saturday, May 14, 2011 23:16 PM
To: obra@list.obra.org
Subject: [OBRA Chat] Track Cogs
I'm a little overwhelmed with all the choices and options in making a
decision about what track cogs to buy. I currently have a generic 16 tooth
on my wheel, and a Soma 17 tooth that I got at CCC.
I want a higher quality 16, a 15 and a 14.
I have Miche Primato hubs, is there any special features about the Miche
cogs and carrier system?
And what about the Q2 alloy?
Any special reason to invest in Dura Ace or Suzue other than durability and
slower wear?
I'm on a budget, and am still figuring out what gear ratios to run for which
events.
I'd rather get a few of the more affordable options and be able to try
different ratios than just get one or two really nice ones.
Any advice?
Thanks!
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