10 speed cassette - number of useable gears?

Discussion in 'Cycling Equipment' started by fastcat, Aug 9, 2006.

  1. fastcat

    fastcat New Member

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    Sorry if this question has been asked before...a quick search didn't find an answer.

    I currently ride an 8 speed cassette, with double chain ring.

    I always avoid the largest-largest and smallest-smallest combination to avoid excessive chain flex/wear.

    As a result of 16 theoretical gears I have 14 useable gears.

    I'm just about to move to a 10 speed set-up, again with a double chain-ring. I'm busy thinking about standard or compact chainsets and the ideal gearing I'd like.

    From the 20 theoretical gears should I assume that again it's just the two extreme cases that are best avoided, hence 18 useable gears ? Or with a 10 speed cassette do I need to extend the concept further by for example not using the largest front-second largest rear for example ?

    Welcome views - go easy on me - first post here ! :)

    Thanks

    Ken
     
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  2. gclark8

    gclark8 New Member

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    20/20 should be ok with a 10 speed chain. They are more flexible and narrower than an 8 speed.
     
  3. lks

    lks New Member

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    I ride Campy Record. On my 12-25 x 39-53, I can cross chain all the way on both rings, without derailleur interference. On my 12-25 x 34-50, I get a slight interference on the 14 x 34 and, while I could trim it out with the shifter and even go on to the 13 & 12, I always just shift back to the big ring and 17t cog. I never cross chain my 39-53 to the max, unless it's just temporary. If you calculate the overall gear ratios for all 20 gear combinations, you will find you have a lot less than 20 different overall gear ratios because of duplications, i.e. overlap. There is more overlap with the Std. vs Compact cranksets. If you are going Shimano, take a look at the 12-27 x 34-50. This gives you a great climbing gear and 40+ mph high gear, without too high a cadence. If you are going Campy, their lowest is a 12-25, if you want the same high gear as the Shimano example.
     
  4. fastcat

    fastcat New Member

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    Thanks guys. Sounds like for 10 speed situation will be close to 8 speed I'm familiar with.

    Lks - I am leaning towards a compact chainset (likely Shimano), but initially with 12-25 cassette, which will give me a few lower gears than I currently have.

    Presently I have 52-39 and 13-23 - lowest gear 45 inch, which I've coped with in the UK, but generally leaves me not able to sustain the cadence I'd like on hills, especially the steep 10%+ ones. And would be impossible in the Alps for me - hence on a brief trip last year I hired a bike with a triple.

    So with a 50/34 and 12-25 I can get 36 inch - significantly lower than my current lowest gear, which should be a good help.

    I'll then see how I get on with that, with the option of swapping in 12-27, which would give me a 33inch low gear, which (as you say) would give me a great climbing gear, which should see me up most climbs, even in the Alps I hope.
     
  5. fastcat

    fastcat New Member

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    But it's funny - even with a 10 speed, there are trade-off's to be made.

    For example, on standard 12-25, there's a jump between the 19 and 17 cogs which is just a tiny bit larger than ideal.

    With a 50/34 it results in a 'missing' 73inch gear (it's there, but on small-small combination). In a perfect world, it would be nice to have it on the large ring, but that would mean needing an 18 tooth cog at the rear between 17 and 19 (obviously!) but in which case I wouldn't want to leave out 25 or 12 to put in 18.....

    Now off to find some cake to have and eat.....:)
     
  6. fastcat

    fastcat New Member

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    Thanks for ther useful link Albert - that's answered my question :)
     
  7. Bro Deal

    Bro Deal New Member

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    Which is one reason why a 12-23 is my favorite cassette. It's a straight block from 12 to 19 with a 21 and a 23. The 53x18 is very useful. The only other option for an 18 is the 13-26, sometimes called a century special.

    If you want an 18 and a 12 and a 25 or 26 then you are out of luck. Maybe campag will come out with 11 speed. :)
     
  8. Albert 50

    Albert 50 New Member

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    I know this is not everyones cup of tea, but I've solved all these problems with my 30 speed 105 50/39/30 12/25. I seem to be able to handle the extra 200 gms or so of extra weight compared to a double & the sooooo [reportedly] complicated gear changing:D BTW not baiting anyone for a double V triple controversy, its just the ticket for me & suits my riding routes & abilities:)
     
  9. Eastway82

    Eastway82 New Member

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    I use the 13-26 10sp campag, with 39/53 front, and it's fine for me – straight through 13-19, then 21/23/26, which gets me up anything round here (although like the original poster I took a triple - 30 fr/26rr - to the Alps and needed it!). I grew up with 13-18 six speed with 42/52 front, so I like to have most of the cassette with 1-tooth gaps, and I typically ride a high cadence (95 average but I can spin 115 easily) so the 'missing' 12T is no problem for me. I tend to use the full cassette on the small ring, with no problems apart from maybe a slight interference on 39/13 (although to make this possible on my bike, which has very short chainstays, I have to run a 115mm bottom bracket to space the chainset out slightly). On the big ring I tend not to go down below the 19T as it just doesn't run as smooth and anyway, I'd usually rather shift back to the small ring as 39/14 is practically exactly the same gear, and that way I can avoid the move to 2-tooth gaps – I just keep the 21/23/26 as bail-out gears on the small ring.
     
  10. fastcat

    fastcat New Member

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    Hmmm - more food for thought - thanks guys ! :)

    The good thing is that you can change to cassette fairly easily to suit different purposes. Hadn't thought of a 12-23, but with a 50/34 would still give me a lower gear than I presently have, with the advantage of the 18 tooth cog. Still with the option to change the cassette for 12-25 or 27 if required.

    The 13-26 is another thought, although with a 50/34 compact the high gear is 101inches, which is perhaps a tad low.

    Which thoughts feed back into decision about standard or compact chainset. I have ruled out a triple though, but thanks for the thought Albert)
     
  11. free_rideman

    free_rideman New Member

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    I run a 9 speed setup with a compact (12-23) (50x34 front). I also use a short cage derailleur. So when shifting in the 34 I can only go to the 6th fastest gear (smaller cogs). After that my derailleur can't take up the extra chain.

    But this doesn't bother me since i can just shift to my larger front chainring (50) and then climb to gear number three (third largest rear cog). But I can't use the first two gears in the back, since my chain line becomes horrible. Talk about flex.

    The point is that technically you might not need your whole range because of the overlap in gears. I can't use three fast gears in my small front chain ring, and two slow gears in my large chainring. But I really don't need them since those two zones I can't use, are really duplicate gears.

    Oh, when you get your setup you will notice how much your chain gets affected when everything is new. This is a good time to see what you can and can't do with your setup. Most times the chain later wears in, and becomes flexible enough to use on more extreme gears. I still never do it though, just to keep a bit more life in the chain. And rear derailleur. If you think, the rear derailleur has some stress put on it too.

    But other than that you should be fine.
     
  12. fastcat

    fastcat New Member

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    Thanks free-rideman - still musing the standard versus compact issue and consulting gearing charts. Decisions, decisions ... ! :)
     
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