hi all - i have a question on cassettes. right now i'm riding an approx. year old 11-27 dura-ace cassette. my question is: since it comes in a number of pieces, can i swap out my smallest gears (the last two, which come as one piece) and move down to a 28 without replacing the entire cassette? i'm on a serious budget (grad student), and need something a little smaller at times for some lighter work outs. can't afford to spend $200+ on a whole new cassette. it seems very doable, but i don't know where i can purchase a subset of the cassette. any ideas???? thanks!

It's enticing, but most likely you'll find loose sprockets (or pairs) hard to purchase at a reasonable cost (if at all). In any case there's little benefit to be gained, because the smaller of the pair (2nd low) has to be larger than it's neighbor by a gap consistent with the 4th-3rd gap. So you'll end up spending fairly serious dough to change an 11-27 to maybe an 11-25, or at best a 11-24, which barely seems worth the effort.

Your best bet is to buy a reasonably priced non-DuraAce cassette in the range you want, and save this one for when you need it. Cassettes are wearing parts, so there's no loss setting one aside for the future, and IMO, not much sense in spending top dollar for them.

Dura Ace cassettes are absurdly expensive since you are paying a huge premium for the Ti largest few cogs and for a minor weight savings. Unless you are running 11-speed, buy an Ultegra or even 105 cassette at a fraction of the Dura Ace price and no sacrifice in performance and, probably, an improvement in durability..

agree, you can save $$ by not buying the top of the line. cassettes can be cheaper. just doing a very quick internet search, i found a 10sp tiagra for $45. or mid-level SRAM 10sp 12-28 for $99.

looks like i'll just be purchasing an ultagra or 105 cassette. thanks for all the feedback!