ahultin

Okay so today I swapped out the 12-25 cassette from my daughters bike to see how much it helped. Two observations I noticed:
1. I did not miss the 11 tooth (at least not on the hilly route) I found that my downhill speed was limited by my comfort level and not my gearing.
2. While the 25 tooth was a noticeable change, Cadance was still significantly hampered by the climb.

My local performance would have to order in the 11-28 which means once it arrives it is mine, work or not so Per request, here are photos of the bike and RD, hopefully this is the right angle to determine if it might work.

Thanks for all the help.

motobecane69

okay, that is the ultegra SS not the GS rear deraileur however from the pic I can see that there is still plenty more room for that deraileur to move. in the pic of my bike you can see that the pulley's are stretched out and pointing forwards a little bit. You will probably need to move the B Screw all the way in or worst case scenario, get a longer B-screw. if your not sure what that is, just take it to your lbs, they will probably do the adjustment for free/cheap.

Based on the specs i read up on, you should be able to use the 28 tooth without a problem. BTW, you could always look on ebay for a used 12-28 just to try it out, you can probably get one for really cheap.



Ultegra GS RD with Ultegra Compact 50/34 crank. I needed the GS RD because total chain wrap capacity becomes an issue with the 16 tooth difference between the front chainrings.

ahultin

Update,
Picked up the 11-28 cassette yesterday and installed it last night. Adjusted the B screw all the way in and everything seemed to be working fine. Rode my normal route this afternoon (while not at normal time, i usually ride first thing in the morning so expect some difference) Average cadence on the climb went from 40 previous to 58. One thing I did notice is while my legs feel less fatigued I was feeling like my heart rate was considerably higher (no monitor so it could be perception) . Also had an issue with not being able to drop to the 11 tooth ring so ill have to tweak with the RD some.
Thank you all for the help

wxduff

The higher heart rate should be expected as your cadence goes up. As long as you weren't out of breath or in the red zone, then that is alright. Climbing is all about finding the sweet spot between killing your legs and killing your heart. I'm sure as you spend some more time climbing at the higher cadence your heart will get used to it.

the_goob

I don't have anything to add, but the information in this thread is great. I do wish I had a few more hills near where I live so I could practice climbing a bit more.

motobecane69

well based on this thread and another one, I decided to swap out my 11-32 for a 12-25. I friggin love it! while the wheelset that has the 12-25 probably should be the one that has the 11-32 because it's a really light wheelset "a climbing" wheelset if clydes can have such a thing I was pleasantly surprised by how much i enjoyed the tighter gear spacing and is there anything more useless for a clyde than an 11T cog? I went down a pretty good sized hill and didn't spin out of the 50-12. I like how the 12-25 challenges me to get more fit. If i were doing a hilly event like a century, I would be smart and stick with the 11-32 because even though I can climb in the 25T I would want to reserve some energy for later but certainly for my regular type of riding and the terrain around here the 12-25 is where it's at. Perhaps a happy medium would be a 13-27? not sure if that combo is even made. (i'm using a 9speed drivetrain)

ahultin

Road my flat route today with the new gearing and was worried I might notice some gaps but found that all was right an well in the world. Since ive been riding the hills lately I was able to maintain an average cadence of 83 and while that may not be spinning to most, it represented a 10% increase from the 75ish I have been averaging. Unless I start to tackle the really steap stuff ill probably stick with my standard crankset and the 11-28 cluster.