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smaller chain ring or new groupset?

I am still recovering from 2 bouts of knee surgery and progressing well. However I am still finding hills a challenge- I drop into lowest gear almost immediately I hit an incline to "save" the knees. My aim when riding is to spin at 80-90rpm- but can't do this on hills of course. If I revert to my previous methods of muscling up the hills and thrashing the knees then I will only damage them again. I keep looking to change down but realise I've gone as low as I can! When I bought my bike the technician there put one larger cog on the cassette to help me but I still feel it is not enough. I am riding a Scott CR1 Team carbon road bike with 105 groupset. Decided to go for a more expensive frame, with the idea of upgrading gears later if needed but not really wanting to change the whole set. Is it possible to replace that larger cog with an even bigger one or does the whole lot have to be changed? Sorry I'm not a bike techie as you can tell!

Any suggestions appreciated. [:D]


  • TTX PROTTX PRO Posts: 225
    Yes it is posible to change your outer chainring.T.A Shimano and FSA all do chainrings.first of all we need to establish what current chainring you are using.is it a 52t or 53t chainring.
  • Well TTX PRO if you read "piglets" original thread they are asking about climbing gears and larger sprockets, not larger chain rings.

    What is your gearing at the moment piglet?

    Whats your biggest sprocket at the back and your smallest chain ring at the front?

    Yes it may be easier and better go smaller on the inner chain ring as this will keep a more even spread of gears rather than changing the sprockets as you may end up with an addition jump between say third and fourth. That way you can easily change it back to your current ring / gearing for flatter courses too.

    Heres a link to the gear chart on the Cycling Time Trials site which should help you see your options.

  • In case your not famailier with the gear chart the numbers in the boxes with the decimal point indicate the distance traveled per peddle stroke.

  • TTX PROTTX PRO Posts: 225
    Alright Ironman.NZ.07. Climing gears.heres what my cycle engineering experiance tells me.you can get a road cassete with a 12-26 but no higher becouse if you have a short cage rear mech it wont take it.Then again you may have to be carefull when changin your inner chainring becouse if the difference between the inner and outer is to great,the front mech might not be able to handle it either.I still need to establish your chainring sizes you have so we can give maximum and accurate advise.It all fare and well us assuming but its your money.the last thing we want is for you to go out and buy somethin only to find it wont work.
  • Piglet - I think you've got a few options...

    At the back:

    1. The rear block - I run a 12-27 on the back that helps me spin up the hills. My rear mech takes that with ease, I could probably go 1-2 teeth higher.

    2. If you are running 9sp & want to go even bigger at the rear you could switch to an MTB/touring block, as they go up to 34t, but the jumps between the gears are higher and may upset your cadence. you would need a med/long cage rear mech.

    Up front:

    3. You may not be able to get less than a 39t small chainring on a standard chainset, but many manufactures are now making compact chainsets that have smaller rings. You loose the really big gears, but sounds like that may remove the temptation to use them!

    4. The final option that would require a BIG change & mucho expense, would be to go for a Triple chainset on the front. You get the extra low gears & don't sacrifice the big ring. Downside is cost. You will need a new Chainset, STI/Ergo lever & proabably a rear mech.

    A reasonable bike shop should be able to offer sound advice.
  • pigletpiglet Posts: 86
    Hi guys

    Thanks for replying. My front rings are 38 and 53 the rear is 12/28. Seeing what TXPro said maybe that's already too big? I have no problem with changing gears at present. It's just this sticky ole knee of mine havng trouble with pushing up hills. I have no problems with my MTB or my touring bike which both have ridiculously low gears.

    Reading what fitness boy said it may be that my bike shop has already set me up as best they can without going to triple chainset ( which of course my ancient MTB has).

    I'll see what you guys make of my current set up

  • Hi again

    Ironman NZ- looked up the link you posted but it was a bit hard for me to relate that to my problem. Sorry I am not very technical. I m heading back to NZ in Nov with my trusty steed so will take the bike back to the store I got it from and see what they suggest. The knee is getting stonger but I am scared to stress it too much- esp on Wellington Hills!

    Thanks for the replies[:)]
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