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Community brainstorming: legal definition of speed limit


em1barns

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2 hours ago, lizardmech said:

Speed limit regulation is silly 25km/h is too fast for footpaths and too slow for some situations on a bikepath or road.

By implication you are suggesting that cyclers who cannot go (or are not willing to go) faster than 25km/h are not suited to go on bikepaths or the roads. That doesn't sound right to me, not even close.

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1 minute ago, Mono said:

By implication you are suggesting that cyclers who cannot go (or are not willing to go) faster than 25km/h are not suited to go on bikepaths or the roads. That doesn't sound right to me, not even close.

It can be an issue going downhill. Last time I rode a pedelec with a rating of 250w 25km/h I had no problem exploiting it to ride around at 40km/h on flat ground. I just put it in top gear and rapidly accelerated so inertia overshoots the speed limit, it's fairly easy to maintain speed unassisted as opposed to manually accelerating to 40km/h each time you slow down and changing gears multiple times.

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4 hours ago, lizardmech said:

it's fairly easy to maintain speed unassisted as opposed to manually accelerating to 40km/h each time you slow down and changing gears multiple times

That might be your perception, but it is just not true. The main reason why it is exhausting to drive 40km/h is the wind resistance at 40km/h (see below link). That is why slipstreaming in sports cycling is so extraordinarily important. AFAICS, accelerating from 0 to 20km/h in 5s takes about the same power [i.e. Watt] as accelerating from 20 to 40km/h in 15s, when disregarding the power needed to keep the current speed.

http://mccraw.co.uk/wind-resistance-cycling-speed/

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On 5.3.2017 at 3:12 PM, lizardmech said:

It can be an issue going downhill. Last time I rode a pedelec with a rating of 250w 25km/h I had no problem exploiting it to ride around at 40km/h on flat ground. I just put it in top gear and rapidly accelerated so inertia overshoots the speed limit, it's fairly easy to maintain speed unassisted as opposed to manually accelerating to 40km/h each time you slow down and changing gears multiple times.

With a pedelec you've no issue if motor power/ torque goes down at higher revs or control board makes a power cut. The problem with the pedelec us stability of the frame and brake power when overshooting vmax. 

Overshooting vmax is a sad problem on an EUC. Being Ben Johnson you may can run out or you you'll do a simple faceplant. Overshooting speed is a test in PLEV. We've discussed it last year in Paris.

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16 minutes ago, OliverH said:

Overshooting speed is a test in PLEV. We've discussed it last year in Paris.

Sounds interesting, how does the test work? 

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2 hours ago, Mono said:

Sounds interesting, how does the test work? 

A couple of km/h more than 25 km/h. That's worthless to talk here about ??

Test case is to see that the EUC will be speed limited to the design speed. Test case is passed if the EUC is limited to 25 km/h down from the overshoot speed. A normal usage is base of the test case.

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