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Thread: e-Bikes - Let's talk

  1. #331
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    A bicycle speed has three components: motor input (pedals and/or electric motor), friction losses (air resistance + tire resistance) and change in potential energy of going up or down hills.

    Riding on the level eliminates potential energy change so all the motor input goes into countering friction.

    Power required (watts) to move a bicycle at speed on the level:

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    (Fun fact, the elf’s body and shape gives it a friction profile more like the race bike than a MTB.)

    Riding up and down hills changes the potential energy of the bicycle. Potential energy is the total vehicle weight and the change in elevation. The table below gives the power required to go up or down a hill for a MTB at the given speed. Empty cells indicate braking needed.

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    One take-away is that if the potential for speed is the key safety issue with e-bikes, then we must also ban heavy people from riding on trails with hills. Even on modest hills, heavy people’s potential energy shedding provides more power than an e-bike’s motor.
    Last edited by SolarBikeCar; 08-08-2017 at 07:21 AM. Reason: Replace tables with images

  2. #332
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    dasgeh is offline Queen of Family Biking & All Things Kidical
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    Quote Originally Posted by Harry Meatmotor View Post
    I'm sorry, I'm calling BS. Dasgeh, I'm calling you out personally. Strava or it didn't happen. Show me the ride where you hit 30mph (easily) on the Custis riding a normal (not 100lb cargo bike). Otherwise, you're spouting misinformed conjecture.

    "Easily hitting 30mph" without pedaling is not possible on a regular hybrid or road bike along the Custis with average folks making 250w (Max!).

    I'm also calling BS on the whole "more e-bike users = better average cycling behavior". The second you give some trailboss, CAT6, pathlete an extra 750w, he's gonna be a d*ck.

    I'm laying out my hand here: There are too many people on this board that think that anything faster than them is "30+ mph". Yet, at the same time, I see the same folks trying to defend e-bike use on the trail where 25+ mph is ACTUALLY EASILY attainable with only (roughly) 200w of rider input on top of 750w+ of e-assist.

    I'm trying to get this straight: It's okay for an e-bike user with limited bike handling skills to "easily" hit speeds in excess of 25mph on a bike/ped trail (because, hay, they're out riding, at least!), yet the second some dirtbag on a road bike does that under his own power, zooming past other trail users, he's lambasted for being an "MF-r" or an "A-hole"?

    Hello! Hypocrisy!
    1) I was specifically thinking about heading westbound: the downhill east of spout run (that currently leads into the puddle) and the last downhill before Westover that you'd have to be crazy to take at speed because of the entrances and blind curve at the bottom. And eastbound, the Roslyn hill that you'd have to be crazy to take at the max possible speed. Nope, I'm not going to strava those for you, but you can go and coast down them and see how fast you can go.

    2) yes, people who so behave like dicks regardless of whether they're on a road bike, ebike or car (I'm leaving out some qualifiers here). It's better for the world if those people aren't in cars. But that wasn't my point.

    My point is that it's very likely that the current biking population is about 15% ahole, while the current non biking population is more like 10% ahole. So getting those currently in the non bike pile into the bike pile (assuming a random sample) will dilute the ahole percentage in the bike pile, making overall biking better behaved. Yep, there will be some aholes, but there will be more nice polite people. And the second you give some nice, normal, polite person a 750w motor, he's going to leave his car at home and pedal to work on time and in a totally reasonable way.

    3) the dickish behavior is absolutely not ok. It's not ok of you're on an ebike. It's not ok if you're on a road bike. It's not ok if you're on an elliptigo. But it's the behavior that's the problem, not the bike. Focus on the behavior, not the bike

    Oh, and a point i keep forgetting to make in respond to people who say "the only people I see pass me are on ebikes and are dicks." If you are riding at the max responsible speed, or at a higher-than-responsible speed, than the only people who pass you are, by definition, riding irresponsibly. You only get limited glances at the people you pass and the people coming the other way, so the majority of your observation of other riders is the people who pass you.

    If you're a fast rider, you may pass 50 bikes -- 10 non-e who are jerks, 10 non-e who are nice, and 30 e who are nice. But you're passed by 3 e who are jerks, all the sudden you may think all e are jerks. Sampling bias.

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  3. #333
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    Quote Originally Posted by Steve O View Post
    You were not coasting or you would have lost a lot more speed between the sisters. You pretty much have to pedal to hit 30+. Unless you are already almost at 30 when you hit the top of the hill, which would have required pedaling hard up the backside. I'm with Meatmotor here: 30+ is doable on that section of the Custis, but you have to put in some work--it's not "easily" possible coasting.
    I think it's pretty easy to hit 30mph on this section - maybe not while coasting but it's not like you have to hammer. I'd call "easily possible" fair - especially if I can do it. It's rare that I hit that speed though because of a combination of trail traffic or (more likely) because I'm just too chicken.

  4. #334
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    Real easy to get all lost in numbers that mean little with regards to the issues.

    An e-bike is a tool just the same as a human power-bike. What you do with a tool matters more than the tool itself. Maxwell's hammer can pound nails or heads.

    More activity and more people can fit in the same space when they are/act more alike. Speed needs to be considered in both actual and differential. Speed needs to be considered in relation to location and condition. Examples... 30 mph down a clear dry empty hill is not unsafe. 25 mph up the same hill while passing people with a 17 mph speed delta might be. e- bike blending in both in speed and size format not unsafe. Human bike not following normal convention is also unsafe. 4 foot wide car like device doing 20+ mph on an 8 foot wide path does not fit the format of users.
    Activities and formats vary, walkers, dog walkers, slow riders, fast riders, bikes, trikes, tandems and the like all need to follow some convention so they can share a common resource. The higher the use density the higher the adherence to convention needs to be. Hard and fast rules tend to chafe against common sense but so do greedy people that use more than their share of a common resource.

    If your actions impact others do what is needed to go with the flow.

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  6. #335
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    Can we drop the "its safe when there is no one else on the trail" thing?

    At least on a trail without a lot of twists its probably (?) safe to ride a motor cycle at 50MPH. Its safe to drive a car on most trails (and in fact LE does just that in many places, even when the trail is not clear, and I have yet to hear of them getting into a collision). Its safe to drive 90MPH on most empty roads. Maybe 100MPH.

    We don't and shouldn't, set laws, either speed limits or equipment limits, based on "when the trail is empty" (we SHOULD focus enforcement on times when violations are most dangerous though).

    For those suggesting making or keeping ebikes legal, but allowing lower limits on wattage or max speed than current limits - IIUC that would effectively mean a ban at least in the short term, because of what is currently in the fleet, and on sale? I mean suppose the City of Alexandria were to allow ebikes on its owned trails (which includes the Holmes Run Trail) but with a speed limit of 18MPH (don't ask me how we actually enforce this) while the lowest speed max on ebikes being sold (is it??) is 20MPH. Until a sufficient critical mass adopts the same standards as Alexandria, and the market shifts, we are effectively banning all ebikes, are we not? (note, personally I am not proposing such a policy, as the Holmes Run Trail in my opinion could probably still benefit strongly from more usage, the only "overcrowded" trail in the City is in NPS jurisdiction, though I also note that most of the Holmes Run Trail is unsuited to higher speed riding, and the Eisenhower Ave MUP has a very bikeable (ofr fast riders) road immediately adjacent)
    Last edited by lordofthemark; 08-08-2017 at 08:25 AM.

  7. #336
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    I think the inability to enforce any ban is ultimately the determining factor, whether you're pro-ebike or anti-ebike. It's sometimes hard to tell whether a bike is an ebike, and as with mechanical doping, I'm assuming the technology will only get more difficult to spot as time goes on. So it's a done deal; ebikes are here and they're going to be on the trails whether you want them there or not. Therefore, we should focus on speed and other behaviors. (Although we can't really even enforce a speed limit; it's proven impossible for cars, and there are fewer resources to enforce it for bikes on trails; still, it's closer to realistic than banning ebikes would be.)

    On the washcycle thread, elizqueenmama and someone who may use a cargo bike and post here a lot make some compelling arguments for ebikes on trails for cargo/child hauling purposes. Long, but if you're on the fence and open to other view points, could prove convincing.

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  9. #337
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    Quote Originally Posted by huskerdont View Post
    I think the inability to enforce any ban is ultimately the determining factor, whether you're pro-ebike or anti-ebike. It's sometimes hard to tell whether a bike is an ebike, and as with mechanical doping, I'm assuming the technology will only get more difficult to spot as time goes on. So it's a done deal; ebikes are here and they're going to be on the trails whether you want them there or not.
    One thing to note about enforcement (and this goes for lots of other things, including Idaho Stops) You may be doing something nominally illegal, that is not enforced by LE, or cannot be enforced by LE. But IF you end up in an accident, and there is any way to determine that you did that illegal thing, it can still be brought up in a civil action. Ergo, it still definitely matters what we ban or allow by law.

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  11. #338
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    Quote Originally Posted by Vicegrip View Post
    Real easy to get all lost in numbers that mean little with regards to the issues.
    Spoken by someone who can't do math or physics but still thinks they know more than an engineer on how to build safe bikes.

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  13. #339
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    Quote Originally Posted by lordofthemark View Post
    One thing to note about enforcement (and this goes for lots of other things, including Idaho Stops) You may be doing something nominally illegal, that is not enforced by LE, or cannot be enforced by LE. But IF you end up in an accident, and there is any way to determine that you did that illegal thing, it can still be brought up in a civil action. Ergo, it still definitely matters what we ban or allow by law.
    Completely true. I only made the statement because, as with speeding and people refusing to use their turn signals or yield the right-of-way, it's going to happen, so at least for me, I feel like acceptance is the only option. YMMV.

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    Quote Originally Posted by huskerdont View Post
    I think the inability to enforce any ban is ultimately the determining factor, . . .
    It is my opinion that the only thing that will work is an industry-wide standard that is tied to a legal standard that is widely adopted. I recommended wattage because it's rather binary and not situational. A bike will always have the same maximum wattage, while a speed limiter doesn't keep the bike from going faster, it only (in theory) cuts out the motor assist. I recognize that this disadvantages cargo bikes, but there are always tradeoffs. The result would be, in a few years' time, in the majority of ebikes being "Class 1" or similar nomenclature, with a higher-powered "Class 2", and "Class 3" being essentially electric motorcycles. This would make enforcement easier.

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