Updating cassette

Christian B
Christian B Posts: 20
edited May 2017 in Workshop
Hi, I'm new to fettling with the bike so need some advice. I haven't yet bought the Zinn book so looking at you guys initially.
I own a b'twin triban 500SE and wanted to update/improve/upgrade the cassette to a larger one. I was wanting to get the Shimano 105 5700 10 speed. Now is it just a case of changing the cassette or do I need to lengthen the chain? Fettle with the derailleur etc or just change it?

Thanks in advance.

Chris

Comments

  • keef66
    keef66 Posts: 13,123
    If the existing cassette is 10 speed then just change the cassette. If there's a spacer behind the old cassette leave it on. Depending on how much bigger the biggest sprocket is you may have to lengthen the chain by a link, and / or adjust the B screw on the rear mech which determines how close to the cassette the upper jockey wheel sits.

    Oh, and if the old cassette had a 12t or larger smallest sprocket and the new one has an 11t, make sure you use the lockring that comes with the new one. A 12t lockring will foul the chain ronning on an 11t cog.
  • Christian B
    Christian B Posts: 20
    Thank you for your advice. After this advice and a bit of googling, it is a 8 speed cassette so unlikely I can do anything to it straight away anyway. Bummer. Its not worth updating the shifters etc too as I may as well have bought a slightly more expensive ride in the first place.

    Thanks for your efforts guys.

    Chris
  • Bobbinogs
    Bobbinogs Posts: 4,841
    Might be worth thinking about what you are trying to achieve first. If you just want a lower gear (as in, a cassette with some bigger cogs on to help you climb) then there are lots of very cost effective options out there but you will have to be careful to ensure that the RD can handle the biggest cog (for example, a standard RD won't take a 32T) and you may need to adjust the B stop and require a longer chain, etc.

    Bear in mind that simply having more gears doesn't make anyone quicker, as such, just makes some of the gaps shorter which helps maintain a more consistent cadence, assuming the range of the cassette is not too large. All my bikes are 9 speed and I do ok, it makes a lot of the components a lot cheaper too and they seem to last a decent time as well.
  • dj58
    dj58 Posts: 2,223
    Spec. says the bike has a triple 50/39/30 crankset, with a 12-25 cassette. You can choose a Shimano CS-HG50-8 in 11-28T and 11-32T. Both would probably work with your existing set up, with the adjustments eluded to above, if your RD is a long cage GS model.
  • Bobbinogs
    Bobbinogs Posts: 4,841
    If the OP currently has the option of a 30x25 then sticking on a 28T cog probably won't be that noticeable in terms of percentage difference...and an 11-32 for 8 speed will have some big gaps but a decent bailout gear at the bottom. It's all a bit of a trade off.
  • Christian B
    Christian B Posts: 20
    Shimano CS-HG50-8 in 11-28T Thanks for that. I think that would be fine for a replacement. I'm sure that would work with a little tweak, although as Bobbinogs has said, it more than likely won't make a difference as its swapping like for like.
    Many thanks
  • lesfirth
    lesfirth Posts: 1,382
    Christian B wrote:
    Shimano CS-HG50-8 in 11-28T Thanks for that. I think that would be fine for a replacement. I'm sure that would work with a little tweak, although as Bobbinogs has said, it more than likely won't make a difference as its swapping like for like.
    Many thanks

    I think you will find the difference noticeable and well worth having.
  • Man Of Lard
    Man Of Lard Posts: 903
    yep - 30-25 to 30-28 is a 10% easier gear - if that's what you're after...
  • The Rookie
    The Rookie Posts: 27,812
    Or even 12%?
    Equivalent to just more than 'an extra gear' based on his current gear spacing of circa 9% per gear.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • gremlin750
    gremlin750 Posts: 4
    I did exactly the same swap (Shimano HG50 11-28 for the 12-25 set that came with the bike) on exactly the same bike and:
    a) no tweaking was needed - it worked straight away; and
    b) it does make a noticeable difference on steep climbs IMO (the 30:28 ratio when using the smallest front ring with the largest rear one is almost exactly the same as using a 32 rear cog with a standard compact chainset which is favoured by many, including some Pros)
  • svetty
    svetty Posts: 1,904
    I find that when it comes to getting up hills easier upgrading my fitness works better than upgrading my bike....
    FFS! Harden up and grow a pair :D
  • gremlin750
    gremlin750 Posts: 4
    Svetty wrote:
    I find that when it comes to getting up hills easier upgrading my fitness works better than upgrading my bike....

    Absolutely - but why not do both :D
  • Christian B
    Christian B Posts: 20
    gremlin750 wrote:
    I did exactly the same swap (Shimano HG50 11-28 for the 12-25 set that came with the bike) on exactly the same bike and:
    a) no tweaking was needed - it worked straight away; and
    b) it does make a noticeable difference on steep climbs IMO (the 30:28 ratio when using the smallest front ring with the largest rear one is almost exactly the same as using a 32 rear cog with a standard compact chainset which is favoured by many, including some Pros)

    Hi Gremlin. That's good news. I think if I can do it with no real tweaking then i'll give it a go if you have the same bike etc. It has nothing to do with fitness at all, purely upgrade.

    Thanks again Gremlin.
  • Christian B
    Christian B Posts: 20
    gremlin750 wrote:
    Svetty wrote:
    I find that when it comes to getting up hills easier upgrading my fitness works better than upgrading my bike....

    Absolutely - but why not do both :D

    Just out of curiosity Gremlin, have you also changed any of the other gear componants eg derailleur (front/back), chain etc.
  • dj58
    dj58 Posts: 2,223
    You may want to consider fitting a new chain with the new cassette, unless your existing chain is new/very low mileage. These are good value at the moment, though you may need to order online, click&collect at your nearest store. 10% off as well if you are a British Cycling member.
    http://www.halfords.com/cycling/bike-pa ... in-8-speed
  • dj58
    dj58 Posts: 2,223
    You may want to consider fitting a new chain with the new cassette, unless your existing chain is new/very low mileage. These are good value at the moment, though you may need to order online, click&collect at your nearest store. 10% off as well if you are a British Cycling member.
    http://www.halfords.com/cycling/bike-pa ... in-8-speed
  • Christian B
    Christian B Posts: 20
    Thanks for all your advice guys. Pointless now as some bastard broke into our shed at the weekend and stole my little pride and joy, plus a gt mountain bike and the wifes carrera mountain bike. Oh, and our cycling shoes and track pump!!!
  • gremlin750
    gremlin750 Posts: 4
    Christian B wrote:
    gremlin750 wrote:
    Svetty wrote:
    I find that when it comes to getting up hills easier upgrading my fitness works better than upgrading my bike....

    Absolutely - but why not do both :D

    Just out of curiosity Gremlin, have you also changed any of the other gear componants eg derailleur (front/back), chain etc.

    I changed the chain (to a KMC X8) but only because the old one broke (before the cassette upgrade, before you ask) but nothing else. Note to self: don't change gear under maximum load....

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