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Changing cassette from 11-25 to climbing ratio.

roubaixtomroubaixtom Posts: 479
edited November 2014 in Workshop
Hi,

I bought a Felt F95 for my winter bike in september and since i got it i have been wanting to change the rear cassette for something i can spin up big climbs. Im used to 11-28 on my roubaix and that seems perfect for me. I have found a Tiagra cassette on chain reaction for £10 which seems reasonable. Unfortunatly for some reason there isn't a 11-28 ratio. Out of the options which would be the best to go for?

Also would i need to get a new chain? and how would i know how much longer to make it?

Thanks in advance

Tom

Posts

  • simonjsimonj Posts: 346
    Tiagra is 12-28 or 12-30 for some reason, or jump up an extra £5 to the 105 11-28. You may need a chain depending on how much slack there is (or isn't) on your current chain, make sure you test big to big in your garage before riding!
  • Bar ShakerBar Shaker Posts: 2,313
    If your bike was put together correctly it is almost certain that you will need a new chain and I would recommend starting at a 12 rather than 11, to minimise the gaps in your mid range being too large.

    You spend a lot more time in these gears (eg the low twenties and high teens) than you do in your 11 or 12.

    It's worth paying an extra £5 for 105. The same goes for the chain.
    Boardman Elite SLR 9.2S
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  • KajjalKajjal Posts: 3,404
    As above think about the range of gears you need and which ones you use most to keep the gaps between the most frequent gears as low as you can. I use a 12-30 cassette as an 11 is rarely used and being hilly where we live sometimes it is handy to have the 30 if I am having a slower day.
  • 105 is only in 10 speed. On my winter bike i have shimano sora 9 speed. The only option for me to get is 11-30?

    How much longer would i need to make the chain?
  • simonjsimonj Posts: 346
    I personally wouldn't make it longer, I'd buy a new one - which will come too long and then shorten it when fitting. If you but a KMC, you probably get a free missing link (snap in/out link) so you can take the chain off later to clean.
  • gozzygozzy Posts: 640
    I wouldn't worry too much about getting 105 over tiagra for a winter bike, unless you're meticulous about cleaning it's going to get worn quicker than usual.
  • Ber NardBer Nard Posts: 827
    No need to limit your choices to road cassettes. MTB cassettes will fit fine and open up your options.

    http://www.chainreactioncycles.com/cass ... 4294963681
  • So, if i went for a 11-30 cassette and deore 9 speed chain all should be well?

    How do i determine the chain length? Is it best to use the big ring to big ring technique?
  • Ber NardBer Nard Posts: 827
    Yes and yes.
  • sigorman85sigorman85 Posts: 2,536
    I'm runing a 12/30 105 with a kmc because I suck on hills works fine for me but spin out on flats sometimes
    When i die I just hope the wife doesn't sell my stuff for what I told her I paid for it other wise someone will be getting a mega deal!!!


    De rosa superking 888 di2
  • StillGoingStillGoing Posts: 5,153
    sigorman85 wrote:
    I'm runing a 12/30 105 with a kmc because I suck on hills works fine for me but spin out on flats sometimes

    Assuming you're using a compact with your 12-30, you're claiming that on the flat you're hitting 40mph plus (cadence of 120rpm) and spinning out? How long is this being sustained for if true?
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • If it helps and without reading all the posts, I have a F95 which is my old bike and now winter bike, it took a 11/32 fine no issues.
  • Mad_MalxMad_Malx Posts: 3,932
    philthy3 wrote:
    sigorman85 wrote:
    I'm runing a 12/30 105 with a kmc because I suck on hills works fine for me but spin out on flats sometimes

    Assuming you're using a compact with your 12-30, you're claiming that on the flat you're hitting 40mph plus (cadence of 120rpm) and spinning out? How long is this being sustained for if true?

    I'm impressed too. Brandle just broke the hour record on 55-13. This is pretty much the same gear ratio as 50-12.
  • Mad_MalxMad_Malx Posts: 3,932
    ^so coming back to the topic, for most riders the smaller jumps is more useful than carring round an 11 that is hardly ever needed. Unfortunately the makers keep pandering to those who think they need the 11.
    And use whatever low (big back) gear you need to get up the hills.
  • keezxkeezx Posts: 1,311
    On a winterbike I would not even bother about a 12.
    Dropping 11 and 12 gives more useful cogs and better chainline on the big ring.
  • ai_1ai_1 Posts: 3,060
    keezx wrote:
    On a winterbike I would not even bother about a 12.
    Dropping 11 and 12 gives more useful cogs and better chainline on the big ring.
    I ordered a 13-25 cassette for my no. 2 bike that I've set up for TT for that very reason. I've managed to spin out with 50-11, but it takes a long straight descent about 85km/h to do it. Not something that happens often.
    On the flat I can't imagine I'll often need a bigger gear than 50-15 and the 13 smallest sprocket means the 13, 14, 15, 16 and 17 will all have reasonable chainlines with the bigring.
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