Can a 12-25 cogset be changed to 12-27 easily?

[emily_in_nc]

Thanks for all the feedback, ladies. I would definitely have the shop do the brake removal if I decide to do that. It's not worth the risk of screwing that up nor paying for a special tool.

As for the cassette change, I have no problem going with 105 but am also inclined to go with the 12-28 Ultegra instead, all other things being equal, as that lower gear can only help, and it's well worth $20 extra to me if that's all it is. But if I would have to change the derailleur for a 28 but not a 27, then I'd go with the 105 12-27 instead to keep it simpler and less expensive. I still haven't gotten around to asking DH if he brought his tools to change cassettes with us here; I know he has done it in the past as I bought a new cassette for my Titus in the past, and he changed it.

I don't have any extra chain links as I bought this bike on Ebay so did not shorten the chain, so that will be a factor as well. Need to discuss all this with DH as he does most of the bike work in this househould.

[Trisk, as an aside, the Pilot fits me extremely well! My Aegis Swift had a 75 degree ST, and I did fine with that from a fit perspective. The problem with that bike was because it had a flat top tube, I had zero standover -- I mean nothing, the TT was jammed up into my crotch. And even with the 650c wheels, since the TT was so short, I had lots of toe overlap. The Pilot has the sloping top tube, so the 47cm size gives me lots of standover and no toe overlap (or if there is any, it's extremely slight). And it came with the setback seatpost I need. I absolutely love the bike (and it was a great deal on ebay for full carbon/Ultegra, which is why I decided to take the risk of getting it), but the gearing is not as low as what I'm used to, and I don't have my Friday here to ride the steep hills. I could ride my MTB, but with Barry on his Trek, I'd be eating his dust even more than I do on a road bike! I *thought* Kansas was flat, but not this part of it!]

Thanks again! I'll follow up and let everyone know what I end up doing.

[goldfinch]

I have an 11-28 105 cassette on the rear (10 speed). That is another option to consider.

[emily_in_nc]

I have an 11-28 105 cassette on the rear (10 speed). That is another option to consider.

Yes, I actually misspoke above, goldfinch. The Ultegra 10 speed cassettes are 11-28 or 12-30.

I asked DH, and he does not have a cassette tool or chain whip here, so when I get a chance to take the bike in, I will likely just ask the shop for an estimate to do the work and provide the cassette. From the research I've done, if I have the medium-cage rear derailleur, I could use the 12-30, which I'd prefer as it would give me a 27 and 30t ring, two additional gears. This would be great when I'm riding in the middle chainring in front, which is most of the time. I hit that 25t cog far too early since I'm used to bikes with more easy gears and am a spinner, not a masher. I'd need my granny chainring a lot less with a 12-30 than with a 12-25. But I'll settle for an 11-28 if that's all that will work without a derailleur change. I looked at my derailleur, and comparing it to photos on ebay, I think it's gotta be at least a medium cage, if not a long. It looks much longer than the short-cage.

We shall see!