40mph safety

General Discussion about electric bicycles.
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rhubarb   100 mW

100 mW
Posts: 45
Joined: Jul 23 2007 10:31pm
Location: melbourne, australia
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Re: 40mph safety

Post by rhubarb » Apr 09 2008 9:10am

I had a nasty stack on my 84V 35A KMX Puma the other day- hit a tree root lump in an otherwise empty car park at around 40kmh, rolled several times. Lots of grazes and bruises but nothing permanent.
If you're getting over 40kmh you need tough gloves and a really good bike helmet at least.
Over 50 kmh and you should consider a motorbike helmet. I'm now using a fibreglass (not ABS!) open face helmet, kevlar jeans, leather jacket and gloves.
20" Super Stealthy KMX Puma (84V LiPO)
26" Fairly Stealthy Giant STP Puma (84V LiPO)
3 x 20" SillyKart Trikes (48V)

knightmb   100 kW

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Location: Franklin, TN

Re: 40mph safety

Post by knightmb » Apr 09 2008 6:06pm

D-Man wrote:Then its official then! Everyone: Knightmb says Its fine to go 50 mph on your ebikes! It is totally 100% ok. Thats it then, I'm going to get the fastest hubmotor available and run high voltage and go 50 mph right down the street in the middle of traffic. It will be totally safe. Hell, I won't even wear a helmet. Whats the point? My ebike will be totally safe at 50 and if I crash into a stationary object, there won't be much left anyway!!! Yeeeeeeeee Haaaaaaaa
Well at least quote what I said :P

The topic was about if the bike could handle the speeds on smooth roads. My experience with mine (which is a run of the mill hybrid urban bicycle) is yes, it works just fine. Now the issue about safety, that's a whole other topic. I do check up on my e-bike before every ride, do the brakes sound / look ok, chain ok, gears shift, no squeaks or rattles, motor secure to front wheel, etc.

I've had many of e-bike rides cut short because of a broken spoke, warn brake pads, etc. And of course, I always wear a helmet, riding gloves, pads, etc. You never see those in my video of course, I'm behind the camera.

So my word here isn't gospel, just experience. When you ride around at +40 MPH all the time then yeah, you can be confident that others who will probably ride slower / less often that the bike will hold up for them. I said 50 MPH because for me, that's the barrier where air resistance and of course the law of physics really come into play where you really notice them. The best speed that I can get my front/back wheels to balance at is 50 to 55 MPH, anything faster and they just can't handle it well (within what I feel is safe anyway). At 50+ MPH, wind starts to move your e-bike around like a sail. So a cross wind or a car zooming by can jar your around at high speeds. So between the amount of damage from a crash at +50 MPH, to keeping the bike balanced and in control while not riding a downhill racer bike that is designed for high speeds, that's why I chose the 50 MPH for your run of the mill bicycle. My canti-lever brakes can still stop me better than a car and my aluminum frame holds up just fine. So if you have anything better than that (steel frame, disc brakes, safety cage, air bags), then you are that much better off than me. I won't dispute that.

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kbarrett   10 kW

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Re: 40mph safety

Post by kbarrett » Apr 16 2008 3:55pm

Dude ... get better brakes.

If you need to warn pedestrians, gaerlan sells those obnoxiously loud horns metermaids use.
Sun EZ-1 recumbent, Heinzmann 450W, 36V16A Ping "Duct Tape" LiFePO4
Evil Smoker ( Schwinn beach cruiser with 49cc two stroke, and a one gallon gas tank )

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