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  1. #1
    Senior Member
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    Just how inefficient are they?

    ... compared, to, say, a cheap MTB. I know it must be very hard to generalize, but perhaps someone has an idea.

    It in fact looks like this. I'm thinking of taking the train from Stockholm, Sweden to Oslo, Norway where nice nature scenery (highlands/mountains) are at a far more accessible distance. Thus I need a foldable bike, which I guess in its dismantled state is small enough to take with you on the regular train.

    From there, the plan is to make a tour into the mountains, perhaps lasting for a week or slightly longer.

    I can do 80-100km rides on my cheap 26" MTB at a fairly fast pace feeling only slightly to moderately tired afterwards. But this is on nearly flat roads.

    So my questions are

    - does it sound insane to do a semi-serious distance (around 400km), perhaps 70 of them will be through seriously hilly up-down-up-down-hundreds-of-meters terrain (albeit paved roads), on a moderately efficient 20" folding bike?

    - What makes do you recommend? Preferably sub-$400. Or, prices aside, what FEATURES do you recommend? Given the primary use I write above, should I look for derailleur based transmission or hub, etc. I know that derailleurs are more efficient but something just tells me they would struggle a lot on a folding bike. Am I wrong? Really want a bike which has a fairly low chance of serious near-irreparible breakdown.

    If I decide to do this trip, it will probably be wise to do it next summer so I get the chance to conform myself mentally(?) and physically to any folding bike I decide to eventually buy.

    All input appreciated
    //Tobias

  2. #2
    Karl Ulrich - Xootr LLC
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    There are three primary sources of inefficiency for most folders:

    1. Wheel diameter.
    With a high-pressure 406mm/20in wheel, you will actually get a bit lower rolling resistance than on your mountain bike, although it won't be as low as on a high-pressure 700c road tire. Depending on the speeds at which you ride, wheel diameter is not too big an effect (perhaps 1-5 percent lower efficiency overall).

    2. Transmission.
    This is the biggest factor for most folders. Internal hubs are not very efficient. I have run experiments and reviewed the literature on this subject. The efficiency of an internal hub gear can be below 90 percent in some gears (and rarely above 94% in the best gears). Compare this to 98 percent for a derailleur system. If you are worried about efficiency, it is really important to pick a bike with a derailleur system (or a single speed). I've tried to convince myself otherwise, but this is just a really important factor for high-performance riding. (Some internal hub gears have a single gear in which the gears are locked, providing a direct drive. They are quite efficient in this gear...but in this gear only. In the other gears, you'll get that "muddy" feeling due to the loss of 8-10% of your power in the gears.)

    3. Riding Position.
    The shorter reach on many folders means you are more upright than on a larger bicycle. This translates into higher wind resistance. Some folders allow you to achieve the same riding position as on a large-wheeled bicycle. Others do not.

    I have raced my Swift Folder in conventional events and finished "in the field." I commute about 120km per week on the bike with quite competitive friends without noticeable disadvantages. It has a conventional riding position, high pressure 406mm tires, and a derailleur system. I would not hesitate at all to do a 150-200km ride on it. People with Bike Fridays report similar results. I would stay away from rigs with internal hubs for such activities. (Not to take away from their usefulness for short or low-intensity trips.)

  3. #3
    Hauja
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    Quote Originally Posted by grapetonix
    ... compared, to, say, a cheap MTB. I know it must be very hard to generalize, but perhaps someone has an idea.

    It in fact looks like this. I'm thinking of taking the train from Stockholm, Sweden to Oslo, Norway where nice nature scenery (highlands/mountains) are at a far more accessible distance. Thus I need a foldable bike, which I guess in its dismantled state is small enough to take with you on the regular train.

    From there, the plan is to make a tour into the mountains, perhaps lasting for a week or slightly longer.

    I can do 80-100km rides on my cheap 26" MTB at a fairly fast pace feeling only slightly to moderately tired afterwards. But this is on nearly flat roads.

    So my questions are

    - does it sound insane to do a semi-serious distance (around 400km), perhaps 70 of them will be through seriously hilly up-down-up-down-hundreds-of-meters terrain (albeit paved roads), on a moderately efficient 20" folding bike?

    - What makes do you recommend? Preferably sub-$400. Or, prices aside, what FEATURES do you recommend? Given the primary use I write above, should I look for derailleur based transmission or hub, etc. I know that derailleurs are more efficient but something just tells me they would struggle a lot on a folding bike. Am I wrong? Really want a bike which has a fairly low chance of serious near-irreparible breakdown.

    If I decide to do this trip, it will probably be wise to do it next summer so I get the chance to conform myself mentally(?) and physically to any folding bike I decide to eventually buy.

    All input appreciated
    //Tobias
    Dahon sells a folding mountain bike .Buy one for yourself.Problem solved.

  4. #4
    Stupendous Man wangta01's Avatar
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    Quote Originally Posted by James H Haury
    Dahon sells a folding mountain bike .Buy one for yourself.Problem solved.
    Genius - what was everyone thinking??
    --
    "I can accept failure, but I can't accept not trying."
    -Michael Jordan

  5. #5
    Banned. folder fanatic's Avatar
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    I know internal gears are not as efficient as derailleurs are. But I chose this drivetrain over the more popular derailleur system because they are far more reliable to maintain than exposed cogs are and what good is a bike if you can't ride it?

  6. #6
    Senior Member
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    Cheap mountain bikes are heavy. Heavy is inefficient. Good-quality folders are not heavy.

  7. #7
    Senior Member af895's Avatar
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    Quote Originally Posted by grapetonix
    ... compared, to, say, a cheap MTB. I know it must be very hard to generalize, but perhaps someone has an idea.

    It in fact looks like this. I'm thinking of taking the train from Stockholm, Sweden to Oslo, Norway where nice nature scenery (highlands/mountains) are at a far more accessible distance. Thus I need a foldable bike, which I guess in its dismantled state is small enough to take with you on the regular train.

    From there, the plan is to make a tour into the mountains, perhaps lasting for a week or slightly longer.

    I can do 80-100km rides on my cheap 26" MTB at a fairly fast pace feeling only slightly to moderately tired afterwards. But this is on nearly flat roads.

    So my questions are

    - does it sound insane to do a semi-serious distance (around 400km), perhaps 70 of them will be through seriously hilly up-down-up-down-hundreds-of-meters terrain (albeit paved roads), on a moderately efficient 20" folding bike?

    - What makes do you recommend? Preferably sub-$400. Or, prices aside, what FEATURES do you recommend? Given the primary use I write above, should I look for derailleur based transmission or hub, etc. I know that derailleurs are more efficient but something just tells me they would struggle a lot on a folding bike. Am I wrong? Really want a bike which has a fairly low chance of serious near-irreparible breakdown.

    If I decide to do this trip, it will probably be wise to do it next summer so I get the chance to conform myself mentally(?) and physically to any folding bike I decide to eventually buy.

    All input appreciated
    //Tobias

    Tobias,

    I had a Peugot folder as a teenager (in the 1980's) that was probably built in 1965. It was a tank, heavy, slow, internally geared hub.

    Since then, I've owned several non-folding bikes - all road bikes, some real rocket ships.

    Folding bikes have come a LONG way and I recently bought a 20" wheel KHS Westwood because I no longer have the space for a full size bike. (and I travel a lot)

    I wouldn't hesitate to do 1,000km (one thousand kilometers) on a folding bike.

    Ulrich summed up the biggest concerns. Avoid an internally geared hub. Derailleurs are easily serviced, durable and inexpensive.

    Buy a bike that fits you well. Test ride anything you're considering buying.
    Put good touring tires on and make sure you have a well designed drive train geared for your intended purpose. Schwalbe Marathon tires are excellent and offer low rolling resistance in sizes to fit folders. (20x1.5")

    Dahon makes a number of 20" wheel models that are highly customizable - adjustable handlebar and seat height, brazons for racks etc. I test rode a couple and was impressed. Also tested the Giant Halfway, a couple of Giatex and the KHS.

    http://www.ncf.ca/~af895/bike/KHS.html

    See these links for some pics of different folders:
    http://nordicgroup.us/fold/
    http://www.atob.org.uk/Buyers'_Guide.html

    In your price range, I strongly recommend the Dahon line. They have a lot to choose from and excellent support.
    Last edited by af895; 07-14-05 at 08:48 PM.

  8. #8
    Senior Member
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    Quote Originally Posted by ulrich
    2. Transmission.
    This is the biggest factor for most folders. Internal hubs are not very efficient. I have run experiments and reviewed the literature on this subject. The efficiency of an internal hub gear can be below 90 percent in some gears (and rarely above 94% in the best gears). Compare this to 98 percent for a derailleur system. If you are worried about efficiency, it is really important to pick a bike with a derailleur system (or a single speed). I've tried to convince myself otherwise, but this is just a really important factor for high-performance riding. (Some internal hub gears have a single gear in which the gears are locked, providing a direct drive. They are quite efficient in this gear...but in this gear only. In the other gears, you'll get that "muddy" feeling due to the loss of 8-10% of your power in the gears.)
    Agreed.

    I had three internally hub geared bicycles. I loved them when I used to commute less than 5 miles because they would work perfectly in the rain and snow. HOWEVER. I would not ride them during the weekend because the hubs were too inefficient and it showed! My Bianchi Milano feels like it has 2 water bottles attached to the rear wheel. It loses momentum real fast and I find myself peddalling all the time just to keep the bike rolling. I happen to like the Sturmey Archer AW-3 speed more than the Nexus 7/8 because it has a direct drive that's very efficient. Unfortunately, the limited number of gears means the hills will be a nightmare. Other than the German Speedhub, there are no other internal hubs I woud go touring with because they don't offer a low enough gear.

    Get a folder with a tripple and save your knees.

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