Help I need smaller gears - what can I do? A GUIDE

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Comments

  • drlodge wrote:
    You need a RD with adequate capacity (36 links), so it depends on what your current RD is...?
    I looked at the back of the RD, and it says RD-4600 I think. Can't be quite sure it's a 6 not an 8 - is there such a thing as an RD4800? Can't find any ref to one??

    Edit: I've now found this PDF, but I'm not sure how to interpret the bits that refer to number of teeth.
    Is the gorilla tired yet?
  • John.T
    John.T Posts: 3,698
    That mech will officially only take a 28 sprocket as the largest but you would probably get away with a 30. 32 would be pushing it but depending on your hanger length (they do vary) you might be OK. If you really want a 32 then a 9sp MTB mech will be fine.
  • Hmm... the more I read, the more confused I get.

    I've found this thing called 'capacity', which seems to be:

    (chainset tooth difference) + (cassette tooth difference), which in my case is:
    (50-34=16) + (28-12=16) = 32

    From the spec on that PDF, it seems that the capacity needs to be 39T or less (so Ok there), and max big cog size = 30T (so Ok there too).

    Which suggests that I'd be Ok with a 12-30 cassette. Ok, so 2T more doesn't sound much, but it's still a 7% change in gearing from 28T to 30T.

    Can someone shed any light on how I'm reading the spec?
    Is the gorilla tired yet?
  • John.T
    John.T Posts: 3,698
    I should have read the PDF before answering. I was assuming a 28 tooth max. You have it right. Total capacity is as you think. It is 34 teeth with a SS (short cage) mech and 39 with a GS (long cage). At 32 you are fine with either. The extra capacity on the GS is for a triple chain ring set up. Your safe max (officially) is 50/34 with 11/30. You should be safe with up to 32 with care in setting the B screw and chain length. If unsure then don't go this far. If you want to get a slightly lower gear you can fit a 33 inner ring.
  • John.T wrote:
    I should have read the PDF before answering. I was assuming a 28 tooth max. You have it right. Total capacity is as you think. It is 34 teeth with a SS (short cage) mech and 39 with a GS (long cage). At 32 you are fine with either. The extra capacity on the GS is for a triple chain ring set up. Your safe max (officially) is 50/34 with 11/30. You should be safe with up to 32 with care in setting the B screw and chain length. If unsure then don't go this far. If you want to get a slightly lower gear you can fit a 33 inner ring.
    Great, many thanks for clarifying.

    It's early days yet - I may find I can get up the hills easily enough in time (I've only had the bike 10 days, after all :) ) - but I think, given how cheap the cassettes are, if I go for an upgrade I'll play it safe and go for a 12-30 initially, and see how I get on.

    Thanks again.
    Is the gorilla tired yet?
  • thefd
    thefd Posts: 1,021
    Ok - one quick question. I have a 53/39 front and 12/27 rear. 105 (2010 model - 5600?). Can I just swap the front rings for 50/34 and will it work?
    2017 - Caadx
    2016 - Cervelo R3
    2013 - R872
    2010 - Spesh Tarmac
  • John.T
    John.T Posts: 3,698
    The smallest ring that will fit on those cranks is 38 teeth. For 50/34 you will need a new chainset.
  • thefd
    thefd Posts: 1,021
    John.T wrote:
    The smallest ring that will fit on those cranks is 38 teeth. For 50/34 you will need a new chainset.
    So I would need to change the cranks as well? Would the front mech be ok?
    2017 - Caadx
    2016 - Cervelo R3
    2013 - R872
    2010 - Spesh Tarmac
  • John.T
    John.T Posts: 3,698
    TheFD wrote:
    John.T wrote:
    The smallest ring that will fit on those cranks is 38 teeth. For 50/34 you will need a new chainset.
    So I would need to change the cranks as well? Would the front mech be ok?
    Yes. You would need to lower it though. May need a link out of the chain too. If it works fine without then leave it alone.
  • smoggysteve
    smoggysteve Posts: 2,909
    THIS THREAD IS OVER 4 AND A HALF YEARS OLD, LET IT GO DUDES!!!
  • Hi all,
    My first post on here - and it's to do with the the very topic of wanting a wider range of gears to aid me up the local terrain that is glorious Snowdonia :) All the biking I've done in the last 10 years or so have been on my trusty old mountain bike that has a triple chainring - it has served me well on road and trail.
    I have now got myself a new road bike last year that is kitted out with Microshift White - 10 speed, and with a compact 50/34 and 11/26 cassette. And surprise surprise - I'm really struggling with the hills around here - and it's a shame to have to adjust my routes as it is a stunning place to ride. I'm hoping to get fitter and stronger, but I still think changing the rear cassette to something like a 11/28 or 12/28 or something would be a wise move for me.
    Can anyone tell me if there would be any problems with doing so regarding the RD as it is a short type. I don't think I would need to be changing the chain as it has only done around 200 miles.
    Any info would be appreciated greatly - thanks!!
  • John.T
    John.T Posts: 3,698
    The rear mech is listed for up to a 28 sprocket and a max difference of 33 so an 11/28 would be fine. You may get away with a 12/30 cassette. It would be OK with Shimano but I have no experience of Microshift.
  • Thanks for that John - good to know. Apparently the Microshift is fully compatible with Shimano and each component can be changed bit by bit with no problems - which was one of the reasons I had no fears of buying this bike - if I didn't like the components, then at least I could upgrade as I go along.
    Very tempting idea, the 12/30 by the way :) I think I will try and go for the 11/28 in the hope that by getting fitter/stronger as the year goes on, then I will be sorted.
    Many thanks once again!! :)
  • ednino
    ednino Posts: 684
    Glad i spotted this topic. I recently bought a Giant Defy and i've done about 50 miles on it so far. I love how fast it is, but noticed i have to use the smallest gear alot on hills.

    I've just looked and its an 12-25 cassette and 35/50 up front

    No wonder it feels hard as my old XC bike had 11-34 :roll:

    ...and the XC bike was about the same weight :|
  • sickbuoy
    sickbuoy Posts: 19
    Would suggest going to a 11-27 or 12/28. I am thinking your chainset is a 34/50 not a 35 which is a compact so you should be fine with either of those. Which groupset is it you have?
  • ednino
    ednino Posts: 684
    It is a giant defy 2 compact

    I've now had a 11-28 fitted by my local bike shop. Loads better now

    thanks
  • gethinceri
    gethinceri Posts: 1,671
    What was the cost of purchase and fitting? I want to do the same on my Trek.
  • LittlePlums
    LittlePlums Posts: 139
    I currently have a Campag Veloce compact(50/34) with a 12-25 cassette. I find myself running out of gears on the longer and steeper hills in the area and find some of the gears are quite "samey". This may be because I am used to mountain bike gearing.

    I would like to increase the range of gears and one option would be to go for a 13-29, but I'm a bit reluctant to lose the top end on my current set-up (12). What I want to know, therefore is, if it is possible to mix and match 2 cassettes to end up with, effectively a 12-29? I understand that Campagnolo have individual sprockets, so in my mind this should be possible, but I don't know if there are any limitations and appreciate that there would be bigger jumps in perhaps the middle gears.

    You help would be much appreciated.
    Pride and joy: Bianchi Sempre
    Commuting hack: Cube Nature
  • This is all incredibly useful. Thanks
  • Paulj700
    Paulj700 Posts: 76
    I currently have a Campag Veloce compact(50/34) with a 12-25 cassette. I find myself running out of gears on the longer and steeper hills in the area and find some of the gears are quite "samey". This may be because I am used to mountain bike gearing.

    I would like to increase the range of gears and one option would be to go for a 13-29, but I'm a bit reluctant to lose the top end on my current set-up (12). What I want to know, therefore is, if it is possible to mix and match 2 cassettes to end up with, effectively a 12-29? I understand that Campagnolo have individual sprockets, so in my mind this should be possible, but I don't know if there are any limitations and appreciate that there would be bigger jumps in perhaps the middle gears.

    You help would be much appreciated.

    I'm in the same boat here, looking for a slightly smaller gear for hills. Miche do a cassette called the primato which is Campag compatible (in fact my bike has a miche 12-25 on it now).

    The do it in 12-27 and 12-29 versions for about £32 from wiggle.
  • hannahk
    hannahk Posts: 19
    This thread is really helpful, especially for a newbie who doesn't know too much about this sort of thing!
  • Boabie38
    Boabie38 Posts: 27
    Hi guys,

    Great thread. After riding a triple for 2 years last year I bought a Giant TCR with 105 gearing 52/39 and 12/25 was really struggling on the long climbs, my mates would spin away on climbs, while I was left grinding away....convinced myself it was down to the beer belly and I would get used it.

    After a year the climbs are only slightly better (cadence can be as low as 65rpm) so I'm now thinking its time to change my gearing.

    What would be the best setup and most cost effective to help with climbing? Do I go to a compact or stick with a standard and change the cassette (if so what would you recommend), would I need to change any other parts? At the moment all parts are 105 and have been used for about a year. Ideally I don't want to lose any topend speed, infact I could use some more, sometimes in 52/12 I spin-out only on descents mind you.

    The good news the beer belly has got slightly smaller.

    I know I have asked many questions..... 4 hours ago, I had no idea about gearing and cogs ratios, but doing some reading I have a gained a little but would really like to hear different opinions.

    Many Thanks

    Mark
  • John.T
    John.T Posts: 3,698
    http://www.chainreactioncycles.com/Models.aspx?ModelID=67228
    Cheapest option is fit one of these. The 12/28 will fit with your rear mech OK. The 12/30 may be pushing it a bit but would probably be OK. You may need a new / longer chain depending on how worn / long your current one is. You could also fit a 38 inner ring which is as small as you can go on 130 BCD cranks. After that you are looking at a compact chainset.
  • Boabie38
    Boabie38 Posts: 27
    Thanks John T,

    As the bikes a year old I was expecting I would need a New chain, that eases
    that cost

    Would a 105 28-11 fit with the rear mech? I know this would cost more, than your suggestion.
  • John.T
    John.T Posts: 3,698
    Yes. The 11/28 would fit. I prefer the 12/28 as I find the 16 sprocket much more use than the 11. I only have an 11 on my TT bike and that is more for a better chain line on the 12. I can not push the darn thing and I am doing over 40 mph before the 12 gets too much. Time to free wheel and recover.
  • Boabie38
    Boabie38 Posts: 27
    Thanks John.T

    12/28 it is then.

    Now these "races" uphill with the boys are going to become a lot fairer.

    Mark
  • Manc33
    Manc33 Posts: 2,157
    I got a road bike with 30/40/50 front chainrings and a 12-25 on the back. I am so weak the lowest gear was far too high for me to get up hills (30 divided by 25 = 1.2) so, I "purged" the cassette, rear mech and chain off my MTB and now the setup is 30/40/50 front and 11-32 back. This gave me a lowest gear of 30 divided by 32 = 0.94 which granted is so low I hardly ever use it, but the point to me is that I still have all the gears I used to have anyway, I actually have a higher high gear because of the 11t sprocket. so the last 66% of the gears are the whole range of what the road bike was and the first 33% is lower gearing. The only downside to this is there is no close ratio anymore.

    If you had to buy all the parts it wouldn't cost that much, you just need a long cage rear mech (Alivio is adequate, £30) then a new chain (£12) and a new cassette (check CRC for discounts, I got a SRAM PG850 for £20) so altogether this can be done for about £65.

    It was either that or I don't get up hills and I didn't buy a bike to never see any scenery. 8)
  • jibberjim
    jibberjim Posts: 2,810
    Has anyone bodged a HollowTech2 MTB crank onto a road bike? The extra width would probably mean that it wouldn't manage to use the outer ring, but would it manage to use the inner alone?

    I'm noodling on the possibility of being able to climb alp d'huez on my road bike with Otter, but I think I'll need a 29 or something...
    Jibbering Sports Stuff: http://jibbering.com/sports/
  • Ouija
    Ouija Posts: 1,386
    Actually, the cups on a mountain bike Hollowtech2 are narrower than on a road one. The interconnecting black axle sheath (or whatever it's called) is longer on a mountain bike HT2 so as to sit the cups 73mm apart but you can easily swap it for a narrower road one, but this would place the outside edge of the drive side cup closer to the frame than on a road HT2, so you'd need to use spacers to get it where you want.

    So basically.

    Mountain bike HT2 = Wider axle sheath... narrower cups.
    Road bike HT2 = Narrower axle sheath... wider cups.

    Since your using mountain bike cranks with a wider axle, you'd obviously need to use a few more spacers on the non drive side and probably a single spacer on the drive side to get it all to work. Remember that a lot of mountain bikes also come with 68mm bottom bracket shells, hence the reason they include spacers with mountain bike HT2 sets. You'd just need to use less than the recommended 2 spacers drive side, 1 spacer other side of most mountain bikes (in this case, 1 spacer drive side, 2 spacers other side).

    Also worth having a few 1mm and 0.5mm spacers to play with instead of the obligatory 1.5mm spacers most HT2 cranks come with.