Join Date: Jul 2010
Location: Montreal Canada
Mentioned: 6 Post(s)
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Tiagra FD triple crank, what sort of teeth diff range can I go?
Hi, my new bike has a Tiagra fd, a 50-39-30 triple crank
Deore LX rd, 11-32 cassette. Specialized Tricross Sport.
While this gear range is fine for my needs, if I ever want to load this bike up and hit mountainous roads, I would like to bring the low gear down a bit. The present 30/32 is about a 25 gear inch, quite low but I had thought of perhaps if needed, putting on a 26 granny which would be in the 22 gear inch region.
Years ago, I changed my touring bike gearing from a 50-42-28 to a 50-40-24, which with the 13-30 cassette was appreciated on some of the tours I did when encountering really steep bits. The low became a 21-22 gear inch low. With the friction fd of the time, this was easy to do and worked without any problems.
Regarding the Tiagra fd and Tiagra brifters, what sort of issues are to be expected with changing the 30 granny to a 26? A fellow on this forum told me that he had this done for his Tricross by his LBS and it was straightforward.
It makes sense that being 4 teeth down means I might have to be a little more careful with not using the smaller teeth parts of the cassette (which I normally never do anyway) as the cage of the rd will potentially be closer up due to the extra slack.
Am I right in understanding that the main issue here is to know what the "teeth" range of the rear derailleur is?
I plead ignorance in this area, so if any of you are knowledgeable with this, comments would be appreciated.