Viewing 19 posts - 81 through 99 (of 99 total)
  • Alfine Hubs
  • flatfish
    Free Member

    Typically though bigger guys will be more powerful though their power to weight ratio will be lower which makes them less good at hill climbing.

    if their less good at getting the power down for hill climbing they're obviously inexperienced riders so it shouldn't affect the hub if you know how to climb???

    mboy
    Free Member

    if their less good at getting the power down for hill climbing they're obviously inexperienced riders so it shouldn't affect the hub if you know how to climb???

    EH? 😕

    Climbing ability/efficiency has more to do with Power/Weight ratio, as clubber mentioned, than technique really. For a given climb at least, where we're assuming something quite long and not technical.

    And again, as Clubber mentioned, a big guy is likely to have a lower Power/Weight ratio than a smaller guy of similar fitness.

    Experience and skill would only come into play on a technical climb.

    SandyThePig
    Free Member

    I have an alfine on my commuter / trainer.
    Done about 8-10000 miles on it now, with no serious problems.

    Its very very good for a high milage bike, and if you can't be fannied with maintenance.

    It does distribute a lot of the weight to the rear of the bike – not sure if I would want that on a mountain bike. It is heavy too.

    flatfish
    Free Member

    what i'm trying to get across is that surely a "big" rider can ride light with experience.

    cookeaa
    Full Member

    Reading about a bit the Description on the IO seems to suggests the Alfine hub produces the equivalent of an 11-38t cassette in terms of gearing range, I also found the Alfine group’s own crankset which is apparently available in either 39 or 45 tooth flavours, suggesting shimano haven’t quite gotten their heads away from the higher geared Nexus tow path pootling application with Alfine, despite what a lot of people are using it for…

    My guess would be (and it is a guess) that one of the mid range gears (4th or 5th ) is 1:1 so whatever your “input gearing” ratio; 32/20, 32/23, 39/28, 45/30? You will actually be running this gear in the middle of your range with the alfine and your range is basically +/– 3-4 steps this ratio either side, maybe ~20% a step?

    I’m currently using a 32/22 chainset with an 11-28t 8speed cassette I was mulling over switching to a 36/22 chainset with an 11-32 cassette to give me a wider gearing range (currently it ranges from ~ 75-20 “Gear inches” with the changes I’m considering I’d get ~ 85-18 Gear inches, and a bit less “ratio replication” assuming I’ve calculated correctly) as it is I spend 95% of my time in the “mid” ring and run out of gears on the flat/road, and use the granny if I’m faced with a nasty climb as the top 4 sprockets are my get out of jail climbing gears, I like having at least a couple of easy gears in reserve, and I could live without a massivly Grr gear but wouldn’t want to be any worse off than my current 11-32 top ratio…

    I know you’ll never get the range of a double or triple x8/9 speed but just how far off of producing a similar gearing spead would an Alfine be? In terms of ultimate top and bottom end gearing? I presume if you want a get out of jail climbing gear you have to sacrifice the taller gears and vice-versa, but is it a massive amount?

    Should I even be considering the alfine instead of yet another 2×8 setup or am I the “wrong sort” of rider?

    TandemJeremy
    Free Member

    An alfine produces the same gear spread as a 11/34 cassette. If used with 32 / 18 gearing the ratios are virtually identical to 32 chainring with an 11/34 cassette Obviously buy altering the ratios you move this up and down the scale. It is equivalent to a 1×9 not 2×9 hence I had to gear right down when I wanted granny gears for the 'puffer.

    I believe one of the intermediate gears is 1.1 but strangely it is no direct drive and still goes thru the geartrain.

    Ask maverickboy for his gearing calculator – it makes it easy to see.

    Mister-P
    Free Member

    The 11-34T spread is if you run the 18T sprocket. With a 20T sprocket you get 12-38T.

    Mister-P
    Free Member

    5th is 1:1

    TandemJeremy
    Free Member

    Mr P – that is a bit confusing IMO to put it that way – the gear spread is the same from the hub – you have just moved it up and down the range by altering the overall gearing. It doesn't matter if you alter the overall gearing at the chainring or sprocket.

    cookeaa
    Full Member

    Ok so if I’ve understood you correctly running an alfine with a 32/20 input ratio gives you a range of 69.3 – 21.9 Gear inches (with a 26” wheel) so quite a spinney range then…

    I like the idea of an Alfine Hub but I think I’ll take the cheap option (for now) and just change my 2×8 setup… I’m sure they’ll up it’s range eventually…

    TandemJeremy
    Free Member

    cookea – do you want a copy of the calculator for gear ratios for the alfine??

    32 / 20 is quite low. I went round GT in 32 /18 and tho I would have liked a lower gear I managed fine.

    cookeaa
    Full Member

    TJ- yes please

    cookeaa
    Full Member

    hang on is THIS what I need?

    TandemJeremy
    Free Member

    Thats the basic info – maverickboy made an excell spreadsheet that is very clever and has all the various ratios, gear inches and so on – you can change the size of the chainrings and see the effects on the ratios – its very clever but I need an e mail to send it to.

    Mister-P
    Free Member

    I like the MPH at RPM function of Sheldons calculator.

    TandemJeremy
    Free Member

    Ah – I didn't scroll down to the calculator.

    cookeaa
    Full Member

    It's alright looks like Sheldon has (had) all the info, I can just bang a new sheet on my existing Gear ratio calculator spreadsheet [/nerd] cheers

    mboy
    Free Member

    Ok so if I’ve understood you correctly running an alfine with a 32/20 input ratio gives you a range of 69.3 – 21.9 Gear inches (with a 26” wheel) so quite a spinney range then…

    Approximately, yes… Depends on your tyre size though of course.

    I like the MPH at RPM function of Sheldons calculator.

    Drop me an email, I'll send you my spreadsheet… It's EVEN CLEVERER than Sheldon's calculator as you can input your own desired RPM values rather than just some presets. It even has all the info there for you on ONE PAGE so that you don't have to keep refreshing every time you want to change something, or view a different bit of information (which was what bugged me about Sheldon's site, so I created my own spreadsheet)! 😉

    It's alright looks like Sheldon has (had) all the info, I can just bang a new sheet on my existing Gear ratio calculator spreadsheet [/nerd] cheers

    Happily send you mine mate… I'm not charging for it… You can just copy and paste any info out of it you want into your own sheet then should you desire… Just drop me an email (in my profile)…

    The 11-34T spread is if you run the 18T sprocket. With a 20T sprocket you get 12-38T.

    11.1-34.2 and 12.4-38.0 respectively if we're being pedantic! 😉

    Reading about a bit the Description on the IO seems to suggests the Alfine hub produces the equivalent of an 11-38t cassette in terms of gearing range

    Hmmmm, that's misleading… Where's James from Genesis, he frequents here a lot… He was asking me at one point about being able to host my spreadsheet from their site for those with gearing questions about the Alfine…

    what i'm trying to get across is that surely a "big" rider can ride light with experience.

    Again, I'll repeat my eariler comment… EH? 😕

    How does experience defy the laws of gravity?

    Mister-P
    Free Member

    James is lurking here somewhere. I will point out the error.

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