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  1. #1
    Senior Member cycle.stig's Avatar
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    Single Speed E-Bike...Good Idea?

    I'm guessing this has come up before but I couldnt find it through a search. I am wondering if anyone has any experience with a single speed e-bike. I currently have a Bionx PL350 kit hooked up to my Norco Wolverine 8 speed mountain bike. I find that I never run into a situation where I have to switch out of the bike's highest gear, and often desire an even higher gear.

    I'd like to hook the Bionx kit up to a lighter bike and thought a single speed may be the way to go to lighten up and simplify the whole setup. I know very little about single speed bikes. Could I expect a single speed bike to work similarly to the highest gear I use consistently on my 8 speed bike? Does anyone anticipate any problems with hooking a hub motor kit up to a single speed? Thanks in advance.

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    I keep my ebike in its highest gear setting at all times when riding it { 18th gear** ...this is because I need that high gear to use when using pedal assist going up hills or on slight inclines....the lower gears arent even used anymore.

    I guess you could set up a bike using the highest gear, and somehow take off all the other front/rear gear combinations...but you really arent gonna make the bike much lighter . I think it would be a waste of time.

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    If you're happy with the ebike now, don't change it.

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    Senior Member cycle.stig's Avatar
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    I meant I'd attach the Bionx kit to an existing single speed bike. Not to modify mine to SS. I am happy with my ebike as is but the kit is attached to my mountain bike and set up as a commuter. I'd like to have my mtb bike and have a dedicated commuter/ebike.
    With this in mind I will soon buy a bicycle to attach my bionx to. And I'm currently considering hybrid/cyclocross/SS/cheaper mtb. I figure if I'm only ever going to use the highest gear why not cut out all the rest while making it lighter and easy to maintain. Only SS e-bikes I've found online so far are a few cheap Chinese versions though so I havnt found any personal experiences on the subject.

  5. #5
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    How fast are you going at top speed? If you didn't use the motor, would the gears be useful? 8 speed bike? What brand is it? I don't think I've seen an 8 speed bike apart from internal gearing. You can change the gearing on regular bikes pretty easily. If something went wrong with the motor could you pedal home?

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    My biggest concer would be the loss of the free weel. Most singl speeds I've seen are direct drive so if you are pedaling or not your pedals will have to be in constant motion. I turned my ebike into a single speed by just ripping off all the derailurs and putting it and keeping it in high gear. I really don't think you would shed very much weight anyhow the gears and whatnot are not that heavy.

  7. #7
    Senior Member cycle.stig's Avatar
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    Quote Originally Posted by crackerdog View Post
    8 speed bike? What brand is it? I don't think I've seen an 8 speed bike apart from internal gearing.
    My bad. It's a 24 speed bike. 8 rear. This is it:
    http://www.norco.com/archives/2009/?id=48a31c9504c3e

    I thought the single speed idea might be a good one but a few good points here make me think it a bit pointless. Thanks for the responses.

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    Here’s a couple of ideas for a SS Mountain bike platform.
    1. Figure out your comfortable leg RPM range.
    2. Figure out the top speed on the flat you and the motor are capable of sustaining.
    3. Work backward from a gear chart like this http://www.sheldonbrown.com/gears/ to determine what ratio will give you the desired RPM range that tops out at your top speed. Play with the different chart settings for gear ratios and MPH at xx rpm.
    4. See what the 40 RPM speed is with the above formula (you have a motor to help) to determine your best gear ratio.
    5. If this works with your hills and where you ride, get a 1 speed BMX freewheel, correct chainring and set up your chainline. Get rid of all the extra gear junk and go for the SS. Simple and lighter is cool. -CC

  9. #9
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    Interesting, as I understand your post, you want to recover your mountain bike to use as a mountain bike, and want to put the motor on a single speed bicycle to use as a commuter? If so, you are not getting very useful answers.

    1. A single speed bicycle is not necessarily a fixed gear bicycle. You would not want to use a fixed gear bicycle, but a single speed with a freewheel should work fine.

    2. Many single speed cruisers have been motorized over the years, and there is no reason you cannot swap your motor to one of them.

    3. The reason for all those gears, is not to make it easy to pedal, but to make it possible for a high performance rider to maintain the most efficient cadence at what ever speed conditions permit. If we are not athletes there really is no reason for all those gears. Most of use could get by with 5 speeds quite well, but of course that is not much of a selling point is it? With a motor to provide some extra push on uphill or upwind rides that single speed you are talking about should work quite well.

    4. I have been thinking lately of getting something like a Schwinn Hinge (single speed steel folder) and motorizing it. The only problem I see with that is it would cost about the same as buying a 150cc motor scooter (I do not have a motor on hand and would have to buy the whole setup), which can keep up with highway traffic, and would be much more fun to ride in the rain than a bicycle, and I already have an antique 3-speed, and a 18-speed commuter (converted hybrid) anyway.
    Graywolf--
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    Longing for a stately old roadster

  10. #10
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    What about a fixed gear e-bike that uses the battery for hills but uses momentum to charge itself on downhills? Anyone?

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    Quote Originally Posted by mrlimozine View Post
    What about a fixed gear e-bike that uses the battery for hills but uses momentum to charge itself on downhills? Anyone?
    Regeneration "payback" is currently about 5 min per hour. There is not alot of velocity in the weight of a bike and rider compared to a car. Even less if your legs are rotating with a fixed gear instead of "coasting" with a freewheel. Not sure I'd want to be permanently hooked up to a motor in a fixie either.

  12. #12
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    Quote Originally Posted by mrlimozine View Post
    What about a fixed gear e-bike that uses the battery for hills but uses momentum to charge itself on downhills? Anyone?
    That is the idea behind the Sanyo Eneloop Bike (which I happen to own). Honestly, it seems that maybe the tech could get better and actually be worth it, but regenerative coasting/braking is little more than a green-speak gimmick right now.
    The recharging action doesn't really add much to the battery, but it does slow the bike down when just coasting at a low speed. That said, I still really enjoy the bike.

    As for the original topic of this thread, I don't know if a single speed e-bike is a great idea unless the engine is very powerful and can assist even in a high gear on a hill. Imho, the whole point of an ebike is to take the pain out of hills and make them manageable, so a lower gear for the hills is kind of important. Obviously, you still need a higher gear the for the rest of the time you aren't climbing.

  13. #13
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    I think that an ebike with five widely spaced gears would be about right. You don't need 24, but just 1 would be too few. I do like to pedal a lot and only a single speed would be rough on my knees - I mean, I got the ebike because sometimes I don't want to pedal too hard but I don't want the motor doing all the work either.

    As for the regeneration, I think that it works great on the Trek Valencia+. On those 10 times a year when I have a tailwind, I can actually end up with more battery power than I started with. I do tend to pedal going downhill with the regen set to 50% (setting 2 of 4 on the Trek), and the brake pads last forever since almost all the braking is regenerative.

  14. #14
    Senior Member cycle.stig's Avatar
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    Quote Originally Posted by mrlimozine View Post
    What about a fixed gear e-bike that uses the battery for hills but uses momentum to charge itself on downhills? Anyone?
    My kit is a Bionx which has regenerative braking built in. But as others have mentioned it's effect is pretty minimal. In addition to regenerative braking when you apply the brakes the motor also has 4 levels of resistance that can be turned on during long descents so you don't even have to touch the brakes. The highest level of resistance eventually brings me to a stop even on steep hills. I imagine this feature would be more effective for charging the battery. Not sure what other kits include it...

  15. #15
    Senior Member cycle.stig's Avatar
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    Quote Originally Posted by graywolf View Post
    Interesting, as I understand your post, you want to recover your mountain bike to use as a mountain bike, and want to put the motor on a single speed bicycle to use as a commuter?

    With a motor to provide some extra push on uphill or upwind rides that single speed you are talking about should work quite well.
    This was my thought exactly. Unfortunately I will likely bail on the idea though. It looks like it might take more work and possibly extra parts to attach my kit to a single speed. I still think a single speed e-bike would work well assuming you never run out of juice mid-ride.

  16. #16
    Senior Member rscamp's Avatar
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    E-assist provides a wider speed range for the bike so a single speed would severely limit when pedaling would be useful/practical.
    Rob

  17. #17
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    Single speed is fine since you most likely won't use the lower gears anyway.

    Just be sure to use a single-speed frame or you'll have to get a chain tensioner. That leads to problems (more parts = more problems).

    I always thought this would make a great E-bike. The frame and forks are all chromoly, and it's a single-speed frame. It would be fast.

    http://www.bikesdirect.com/products/dawes/deadeye.htm

    I'm two-tired to ride today.

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