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  1. #1
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    Exploring IGH Conversion

    Looking for advice or suggestions.

    Have been considering changing to the Alfine 11 IGH for my next bike. I'm currently riding a 2010/11 Giant XTC2 29er. Cassette is 12-36 (9 speed) with 22-32-44 chainrings. I am very new to all of the calculations and theory around ratios, gear inches etc but have had a go and this is what I have come up with. Please be gentle with any input as I am willing to take on any constructive critisism and learn from it.

    We know the Alfine 11 has a spread of 409% so I have been doing most of my riding of late deliberately staying off the largest chainring but I have calculated (rightly or wrongly) that this still would be a range somewhere around 435%-438% depending on who's calculator you use.

    If I were to change the cassette to a 12-34 this would bring it down to somewhere between 410%-412% which would give me a truer indication of what riding with the Alfine 11 would be like without the expense, however this brings me to the next delimma. Choosing an appropriate chainring and cog to match as near as possible an equivalent setup, because as near as I can tell, its going to be a 28-23 combination which seems very low, not to mention way out spec for what shimano would recommend.

    Please remember these are the musings of an absolute novice on this subject, but any input from others who know their stuff or have had success in what I'm trying to achieve would be appreciated. Cheers.

  2. #2
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    I think you're on the right track. Sheldon Brown has a gear calculator to help out your calculations:

    Sheldon Brown's Bicycle Gear Calculator

    In or out of Shimano spec (in my mind at least) doesn't matter much. Most people riding alfine on MTB setup are out of spec right out the door. The important question you need to ask yourself is how important is that super low 22/36 gear you have now? Do you ever use it?

    Assess your riding style first. Figure out which low gears you actually use and then go to the calculator to figure out your chainring/cog sizing. Use gear inches in the calculator so you can compare apples to apples. Cogs are cheap - like $10 shipped on amazon - so don't be afraid of experimenting.

    Personally, I'm getting ready to move the gearing upward on my alfine 8 (smaller cog) as I'm starting to outgrow the need for super low gearing and would like a bit more top end speed.

    Your setup is a personal thing. Its going to be different from me or anyone else and you may want to change it over time anyway. Don't worry about what "right" for other people.

    Have you considered how you're going to tension the chain? Looks like your frame has vertical dropouts. I suggest magic gear because its quiet and I like the simple SS look of it, although its finicky to set up.

  3. #3
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    Hey, thanks for your comments. Have found Sheldon Brown's website very helpfull. You get a thumbs from me. Let me know if it hasn't come through. Had some probs with this site of late.

    Where I live and bike to work is very flat so I tend to use the upper range of gears but most of my recreational riding is done in fairly steep and technical trails and I have found I really needed those low gears. Going to 'Mapmyride' this Wednesday to analyze a typical day out for me and see if I just need to get fitter. It's more an issue of stamina for me rather than strength.

    Yes my bike has VD (vertical dropouts) and while I like the idea of magic gear I think I will be going with the Yess tensioner. Have never heard a bad word about them and thinking my next ride will be FS anyway. At the risk of Hijacjking my own thread I'm considring the Giant Anthem as it's such good value for money which is why I bought the XTC in the first place, and Giant seem to be a really good reliable brand. Although I've really yet to start researching the different types of suspension setup properly.

  4. #4
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    The only way you're going to be able to keep both ends of the spectrum is to keep your front derailleur/crankset. If you get a 2 jockey tensioner, that could be possible, but bear in mind, if you go with a rear suspension bike you could end up using the full run of tensioning for a single chainring. Its something you'll have to experiment with.

    You might want to think about 2 bikes - one a dedicated commuter. I don't know where you live, but I sure as hell wouldn't commute on an expensive bike here in NYC! ;-)

  5. #5
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    Had thought about the two ring crankset but in my mind it sort of defeats the purpose of the uncluttered look I was trying to achieve with the alfine. I do have a second bike sitting there collecting dust. Its my first entry level 26er which I have kept as a backup or a spare for friends etc who wanted to have a go, but I have been thinking about putting street tyres on it and riding to work on that.

    Where I live (Mount Maunganui, New Zealand) is only about 7km to work and we are able to lock our bikes up securely under cover so I'm quite lucky in that respect.

    Rohloff is the other option but the price is rediculous and way out of my budget. Had a quote to convert my current bike and it just wasn't feasable. Even if I did everything myself bar building the wheelset I still couldn't justify it.

    Big ride today so will see how I go limiting my use of the lower gears. Might post my analysis of the ride here if it's not too embarrasing.

  6. #6
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    Just found this cool gear calculator:

    http://www.gear-calculator.com/#

  7. #7
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    Wow. Probably the best gear calculator I've seen. Thanks.

  8. #8
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    You could run a Hammerschidt front system and a alfine rear. That would give you all the gearing you would need and a clean look.

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