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  1. #1
    Senior Member JonnyHK's Avatar
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    Being clever, or being too clever. Frame spec ideas.

    I have a plan - a bold plan - to replace my single speed commuter with a new bike that I would get built up for me by a local builder. This will be the "Supa Commuta"TM - designed to be more clever than the average bike!

    I'm in Hong Kong and these guys are in China (Shenzhen, just over the border), so easy and clear communication is going to be a problem. With this in mind, I'd like to bounce my ideas off you guys before I wander into another language.

    Here is my plan.

    Starts simply enough. Lugged steel frame, probably Reynolds 525. Traditional geometry (flat top tube) etc etc.

    Here is where I start to get a bit cute.

    I'd like to run it as a single speed for now, but have the option of running it with an internal geared hub (possibly belt drive) or even with an older 7/8sp groupset in the future.

    I think that using sliding dropouts (like Paragon's) will make the single speed and internally geared hub work ok.

    If we add one of these from Paragon, we can do the belt drive. Why belt drive you ask? Everything gets rusty and crusty in this town AND maybe I just want to be too clever/stand out a bit.

    To go with a derailleur, just swap the dropout part.

    Now I have a couple of questions:
    Dropout Spacing

    If the single speed hubs (flip/flop track) are 120mm, then dropouts at this will be fine for these wheels and also for many 3/5/8 speed geared hubs (Shimano, Sturmley Archer).
    However, many multi gear derailleur based groups would require 126mm spacing. Should I spec the bike at some thing like 122.5mm and tighten it up as single speed and stretch it a bit as geared? A couple of mm is not too much to cold set or just to ignore?

    Braze on specs
    Also, what braze ons will I need to have to accommodate all these uses?
    - Standard ones for rear brake - check.
    - Two stop on downtube or steerer to allow for front/rear derailleurs using STI or bar end shifters - check.
    - Cable stop on chain stay for RD - check.
    - Different cable stop on chain stay (opposite facing?) for geared hub?
    Can anyone advise?

    Am I being too adventurous to try to plan for so many possibilities?

  2. #2
    Randomhead
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    As a framebuilder, I don't think I would want to do this. My suggestion is to build for what you want and if your needs change, figure out how to change it later.

    Certainly you can plan for IGH/Single speed. I would go with 130 spacing. The only issue I can see is chain line with the SS/IGH. New derailleur setups are all at least 130 unless you can live with one of the strange 4 speed modified systems. Pretty sure the newer IGH come in 130 spacing, and SS certainly do. I probably wouldn't bother to provision for a rohloff unless it is very likely that you would get one. The belt drive is no problem.

    I just finished the braze ons for my commuter yesterday. There was a big bag of them. Fender eyelets and rack eyelets. Rack mounts, another set of rack mounts for a trailer/snowplow/street sweeper. 3 water bottle fittings repurposed for a chain case, water bottle fittings in the traditional spots. I'm using a Sturmey Archer dyno 3 speed IGH, so I put a braze on for the pulley at the downtube. I also put a stop at the head tube. A braze on for the tail light/electronics on the left chain stay. 2 braze ons for ease of fender mounting. Finally, there are brake cable stops on the top tube.

  3. #3
    Senior Member bigvegan's Avatar
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    Quick question - where are you finding belt drive parts?

    I have mixed feelings about belt drives myself, but even if I wanted to do one, finding original / replacement cogs / chainrings / belts has proven pretty difficult.

  4. #4
    Randomhead
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    Quote Originally Posted by bigvegan View Post
    Quick question - where are you finding belt drive parts?

    I have mixed feelings about belt drives myself, but even if I wanted to do one, finding original / replacement cogs / chainrings / belts has proven pretty difficult.
    It doesn't surprise me that they aren't particularly easy to get at this point. But if you're getting a frame made adding the provisions for it doesn't hurt anything.

  5. #5
    Senior Member bigvegan's Avatar
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    Quote Originally Posted by unterhausen View Post
    It doesn't surprise me that they aren't particularly easy to get at this point. But if you're getting a frame made adding the provisions for it doesn't hurt anything.
    True, but if you're never going to do it, I'd think it'd be better to have the seatstays brazed / welded in place, rather than to have one of them screwed on. YMMV.

  6. #6
    Senior Member JonnyHK's Avatar
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    The Gates Carbon Drive stuff is available on the Universal Cycles website plus I am sure that there is a direct channel for frame builders.

    Unterhausen: I'd love to see a picture of that frame that you have done for a SA hub.


    It may be a bit too much of a stretch for the one frame to do all. Perhaps I should just go straight into the IGH equipment now rather than fooling with the single speed. At the moment I get around most of my commuter places in one gear (42x16) but sometime I do get caught out with some hills. In Hong Kong you can get some short sharp stuff down in town.

    An Alfine/Nexus hub can run 126mm if you fool about with the spacers, but is standard at 130mm. This is the only hub that I can get a road style brifter for (Versa VRS8).

    Another thought...Would it make sense to put a longer axle and some spacers on a single speed hub so that I can run it at 130mm dropout spacing?

  7. #7
    Randomhead
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    The only problem with re-spacing a ss hub is getting the chainline right. I checked with White Industries, you can get their ss hubs in 130. You might have to re-dish the wheel to fix the chainline on hubs made for 120 spacing.

  8. #8
    Senior Member JonnyHK's Avatar
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    Quote Originally Posted by unterhausen View Post
    The only problem with re-spacing a ss hub is getting the chainline right. I checked with White Industries, you can get their ss hubs in 130. You might have to re-dish the wheel to fix the chainline on hubs made for 120 spacing.
    Thanks for the tip on the White Ind hubs.

    I'm starting to think that I'm being a bit too hopeful on this project and that an off the peg frame/bike might be a whole lot easier.

    Kona has a few good looking ones (some disk, some canti brakes), there are the Trek Portland etc bikes and I even saw a really cool looking Lynskey (Crosstown) that might be a good one for the belt drive and might not cost that much more than building the custom one.

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