Shane Gibson

Hey all,

Last year I raced a 1x10 in CX. Generally speaking, the gearing ratios I
selected worked really well on all of the courses for me. I ran a 44 tooth
ring up front with a MTB cassette (11-36) in back. Gave me all of the
range I needed to climb almost every single hill that most racers had to
run. However, I had lots of problems with chain slap.

I'm trying to optimize my chainline to reduce chain slap. Last year I ran
a SRAM long cage derailleur, but I think I don't need a long cage. The two
things I was considering to correct the chain slap and subsequent
derailment issues I had:

* move to a medium cage MTB derailleur
* use one of the new SRAM "Type 2" one way roller clutch derailleurs

The "Type 2" was designed specifically to keep the chain line tighter, and
reduce slapping. I'm running Shimano's version with the "Shadow Plus"
switch on my MTB, and have been very impressed with how much this mechanism
reduces chain slap.

So - the big question - If I'm reading the way "chain wrap capacity" for a
derailleur is calculated, I'd do:

44 tooth front ring - 11 tooth small rear cog = 33t capacity

SRAM advertises 25t, 35t, and 47t for their short, medium, long
respectively. This means I should be fine with a medium cage. Am I
interpreting this correctly? I was considering switching to a 48t up
front, but that would make the chain wrap capacity 37t - which is out of
spec for a medium cage, but okay for a long cage. The biggest ring I could
run up front would be a 46t (i.e. 35t wrap capacity) with a medium cage.
Anything else I should consider? Thanks!

~~shane

--
"Opportunities multiply as they are seized." - Sun Tzu