I just made this very change, from an 11/23 rear cassette to a 12/27
(Ultegra) 10-speed with a 50/36 on the front. The mechanic at Performance
Bike said that the original chain length seemed fine.
What an enormous difference it has made in the pedaling. I now have two
"granny" gears and it has made hill climbing much more manageable. I am a
relatively new rider (< 3 months) and I am 56 years old. So, I was really
struggling with the original factory setup. I have also found that I can
sustain a cadence around 90-100 with this new gearing whereas it was more
like 75-85 with the original cassette.
Note: On my last ride, yesterday, the chain derailed (proper
terminology?) -- first time that has happened in 300 miles. I was shifting
from the 50 to the 36, but I don't recall which rear cog I was on at the
time. Fortunately, no fall. I just stopped and placed the chain back on
the teeth and continued. No more mishaps on that trip. Maybe I stopped
pedaling for an instant...I don't know...it happened so fast. Could that
incident be an indication that the chain length might not be right?
Anyway, I'm being much more cautions, when shifting, to be sure that (a) I
am pedaling and (b) I am not mismatched between small/large cogs rear to
front.
Ken Bour
<
[email protected]> wrote in message
news:
[email protected]...
> Hi i have a 36/50 compact i need to no if i can run a 12/27 cassett i
> am currently running a 11/23 very tough gears as i dont do much riding
> will a 12/25 make the difference .
>
