Cassette Question

TMR
TMR Posts: 3,986
edited February 2011 in Road beginners
If I swap from an 11-25 to an 11-28, am I right in thinking that I'll have a lower 'low' gear? Is it worth doing? What am I losing?

I don't understand the gear progression from 11 onwards, I guess some of the gears in between must differ from the 11-25?

TIA.

Comments

  • mattshrops
    mattshrops Posts: 1,134
    you will get a lower low gear, all youre losing is some of the smooth transition between each gear- there will be more of a jump between each gear. No big deal.
    Im not sure if all manufacturers short cage rear mech will work with a 28? try it you might need to make a small adjustment (the other screw- that you never adjust)
    on my ultegra a 28 works fine
    Death or Glory- Just another Story
  • A 28 sprocket is about the largest you can run on a road bike.

    Also note that the chainrings on your chainset will also be available in different sizes. In fact, chainsets come in two flavours: A standard double chainest might have rings of 53/39 teeth; a so-called 'compact' chainset might have rings of 50/34. Having a 34 ring at the front makes going up hills a whole lot easier than going from 11-25 to 11-28.

    Compact chainsets usually require a different front mech.
  • TMR
    TMR Posts: 3,986
    Thanks. This is for Compact 2011 105.
  • brin
    brin Posts: 1,122
    Why not just fit 12-27 which gives a good range of gears for what you will probably need, without the big jumps.
    You most likely won't use the 11t often, if at all, and a 34/27 combo will get you up most hills.
  • ADIHEAD
    ADIHEAD Posts: 575
    I've got wheels with 12/25, 12/27 and 11/28. For general riding 11/28 is the best for me, smoother peddling and speed on the 11, 28 doesn't feel a lot different to the 27 but nice to know it's there for hills 20% plus.

    Give it a go and if it annoys you, swap back - it's only a £40 cassette after all and you'll get something back on 'the bay' if you don't get on with it :wink:
  • neeb
    neeb Posts: 4,470
    As others have said, you will gain a significantly lower gear but the jumps between at least some of the gears will be greater. This does actually make a difference as you may find it more difficult to find the "sweetspot" for your cadence, especially on longer climbs.

    A 28 sprocket combined with a compact (34 chainring) is a very low gear. Are you sure you need this? A 27 sprocket will still feel like one more extra lower gear compared to a 25, and you may find that you don't need the 11 sprocket and could make do with a 12, in which case as brin says, a 12-27 would be a good solution (giving you the gears you need while keeping the gaps as small as possible).
  • Mike67
    Mike67 Posts: 585
    . In fact, chainsets come in two flavours: A standard double chainest might have rings of 53/39 teeth; a so-called 'compact' chainset might have rings of 50/34. .

    Don't forget the oft frowned upon triple chainset for duffers like me who live up great big hills and have to ride up it to get home at the end of 50miles :D

    For info the triple chainset has a third chainring at the front usually with 30 teeth.
    I didn't use mine today but it's always there should you need a bail out for any reason.
    Mike B

    Cannondale CAAD9
    Kinesis Pro 5 cross bike
    Lots of bits
  • pianoman
    pianoman Posts: 706
    I think Miche do a 12-29 10 speed Campagnolo one now as well, might get one for the likes of the Cheshire Cat this year. 34/29 would surely be as good as most triples, right?
  • PV586
    PV586 Posts: 12
    PianoMan wrote:
    I think Miche do a 12-29 10 speed Campagnolo one now as well, might get one for the likes of the Cheshire Cat this year. 34/29 would surely be as good as most triples, right?
    Well, on my road bike I've got 46-36-26 and a 14-25 cassette. I find that I can go up steep hills faster than many other roadies (even ones compact doubles) by dropping to my lowest gear.
    To me this 53 teeth chairing stuff sounds a bit mental - to go at a decent cadence on higher gears you have to be doing almost 30!
    Looking at a gear ratio calculator, I can do 25mph at a cadence of 100rpm and that's fast enough for me 8)
  • neeb
    neeb Posts: 4,470
    Looking at a gear ratio calculator, I can do 25mph at a cadence of 100rpm and that's fast enough for me
    Personally I wouldn't want to have to be spinning away like a hamster at 100rpm every time I'm doing 25mph... :)
  • PV586
    PV586 Posts: 12
    From my experience and from the advice of others roughly 90-100 rpm is the cadence to aim for.
  • Mike67 wrote:
    Don't forget the oft frowned upon triple chainset for duffers like me who live up great big hills and have to ride up it to get home at the end of 50miles :D
    .

    I am exactly one of those duffers. However, instead of a triple I now run a 34/42 double.
  • paul64
    paul64 Posts: 278
    The marketing blurb and cog details you need says:

    The latest Shimano 105 Cassette, now dubbed CS-5700 in Shimano-speak, is available in more tooth ratios than ever before. It still provides smooth, quiet, and crisp shifting performance, and it can be used with any Shimano 10-speed drivetrain. For this latest 105 incarnation, the gap to Shimano's more expensive cassettes has been narrowed -- the new design uses an alloy carrier for the largest cogs to shave weight. The real difference in comparison to Ultegra cassettes is the shinier finish on the cogs and the steel lockring on the 105 instead of the lighter alloy.

    The Shimano 105 10-Speed CS-5700 Cassette is available in five ratios -- 11/23, 11/25, 11/28, 12/25, and 12/27.

    The 11-23 includes: 11,12,13,14,15,16,17,19,21,23
    The 11-25 includes: 11,12,13,14,15,17,19,21,23,25
    The 11-28 includes: 11,12,13,14,15,17,19,21,24,28
    The 12-25 includes: 12,13,14,15,16,17,19,21,23,25
    The 12-27 includes: 12,13,14,15,16,17,19,21,24,27





    But hopefully this will help you understand the above. You need to get the feel of how big or small the gears you are comfortable with. Then whether you prefer a lot or little of overlap, can put up with big gaps or small gaps etc. People differ in their preferences:

    105gearratios.jpg
  • John.T
    John.T Posts: 3,698
    They should scrap the 11 and get a 16 back in the 11/28 cassette. The gaps on the 50 ring are just stupid. If you need a 29 then you do not need an 11. Just freewheel.
    I use 12/27 but would not mind changing the 27 for a 28 as insurance.
  • neeb
    neeb Posts: 4,470
    Of course if it was campagnolo 11sp you'd have an extra sprocket to play with.. :wink:

    Campag seem to get a lot of flak for the 11sp thing supposedly being just a marketing gimmick and not necessary, but an extra gear is an extra higher sprocket or a gap removed. The more the better as long as it all still works (which 11sp does).
  • John.T
    John.T Posts: 3,698
    Yes. A 12/27 11sp that included an 18 would be my 'do everything' cassette. I have too much Shimano stuff to even consider changing though.