Bicycle Mechanics - Easier Gearing on my Trek 2.3 (50/34 and 11-28)

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jffielde
09-08-11, 07:05 PM
I'm getting into road biking, but I'm not in great shape yet. I have a compact duo crankset, but I would like to have easier gearing available for hills. It appears that switching to a triple crank entails more than I want to tackle, but I would like to know whether I can replace the 34t front front chain ring or replace the cassette in the back to provide for easier gearing. Thank you.

My bike is here:

http://www.trekbikes.com/us/en/bikes/road/sport/2_and_1_series/2_3/#/us/en/model/details?url=us/en/bikes/road/sport/2_and_1_series/2_3

Crank:
Shimano 105, 50/34 (compact)

Cassette:
Shimano 105 11-28, 10 speed


Badgerjohn
09-08-11, 07:10 PM
I am by no means an expert, but I just switched out my freewheel for the same reason. I moved from So Florida flat land to the Manie mtns and it was killing me. The lbs put larger gears in back and it is much better. My bike is vintage so it is a freewheel and not a cassette, but both are easy. Cost like 35 bucks with install and adjustment. Others here may provide better insight.

8Fishes
09-08-11, 07:35 PM
It is easier and probably cheaper to replace the cassette. Then you don't have to get a new front shifter/derailleur.


mconlonx
09-08-11, 07:56 PM
Get a 10sp mtn cassette -- 11-34 or even 12-36 -- and a Shimano 9sp mtn derailleur. Those will play nice with your 105 10sp shifter. Your shop should be able to hook you up with parts and install, probably $200 ballpark with 105 equivalent mtn components.

dsbrantjr
09-08-11, 07:58 PM
jffielde: You can change to a cassette with larger cogs but you will need to ensure that the rear derailleur can both handle the new largest cog AND wrap a sufficient number of chain links (the difference between the smallest and largest chainwheels added to the difference between the smallest and largest rear cogs). You will also need a longer chain. If the chain is not long enough you risk disaster if you shift to the large chainwheel/large cog combination.

joejack951
09-08-11, 08:00 PM
Because of the size of the bolt circle on your crankset, you cannot go lower than a 34T ring (well, 33 but those are few and far between). As stated above, your best bet is to swap the cassette bearing in mind that you will now have larger gaps between shifts. Depending on your riding style, you may want to consider either biting the bullet and converting to a triple or selling your current bike and getting something with a triple.

jffielde
09-12-11, 08:09 AM
Thank you all for the info. I'll go the route of the cassette and rear derailleur / chain as suggested. Joe.