I found a gizmo that will triple the speed of my ebike

[tuscanyswe]

Originally Posted by adub

I find it odd that you can go out and buy a car with 700+HP and will do 350km/hr+ yet they put governors on ebikes so they won't exceed 28m/h??

Well you need a license for a car to prove you can drive it and know the rules and laws controlling it.

With a bike there is no such training or license and you dont need to know nothing at all to ride one. + its meant for enviroments like bike paths where they will be mixing with other traffic ranging from maybe 10 mph to 28 (or more). Its not safe to go any faster imo (hence why i ride in the traffic instead).

That said i dont think cars should be allowed to go 350km/h either. I remember my dad use to say faster cars are safer as you can make quick overturns and what not (while driving like an idiot for most of the time) and thats likely true if the power was just used for fast acceleration when needed but thats not really the case for most users of these cars..

Volvo is taking a step in the right direction with limitiing their cars to 180 km/h.
Its a sensible thing to do imo but it may be tough before lots of other brands follow.

[Mark McM]

Originally Posted by Nomadmax

That's pretty impressive. Can you post a video of you doing that?

Sorry, I've got no videos of me roller racing, but here's a video of a typical race at my club's roller race series(Northeast Bicycle Club in eastern Massachusetts):

https://www.youtube.com/watch?v=Wy8WTeQ2Pq8

Here's a better produced video of a different roller race, which shows some people who are obviously faster than me:

https://www.youtube.com/watch?v=XTWosws_KT4


Most roller races are short (typically 1K or less), and the cadences can be quite high (sometimes over 200 rpm). For a few years, our club also did 3K races, which I would do in about 2:40 - 2:45. With the USCF gear limit (max. 7.69 m development), that means about 150 rpm. average.



Here's a page about the Bike Works NYC Roller Races, where they go into some detail about gear limits and cadences. Notice the mention of cadences in the last two paragraphs:

The thing about roller racing is that each performance can be accurately calculated by cadence, development, distance and time. We can see how this plays out in a 500 meter event by comparing two racers with different cadence and development. Imagine one racer riding a road bike with a 53 x 15 on 700 x 23 clinchers, giving 7.40 meters development. The other racer rides a track bike with a 48 x 13 on 27" x 19 tubulars, giving 7.66 meters development. That's a 26 centimeter advantage per pedal stroke.

Furthermore, in those 500 meters, the road rider can expect to do exactly 67.5 crank revolutions, and the track rider will do 65.2 revs, two less pedal strokes over the same distance. Then the time to beat is 18 seconds. Roadie must do 3.75 revolutions per second, an average cadence of 225 rpm, while trackie has to do 3.62 revs per second, an average of 217.5 rpm.

[tuscanyswe]

Originally Posted by Mark McM

Sorry, I've got no videos of me roller racing, but here's a video of a typical race at my club's roller race series(Northeast Bicycle Club in eastern Massachusetts):

https://www.youtube.com/watch?v=Wy8WTeQ2Pq8

So does everyone use supershort cranks in these events? Are they limited even?

[Elefantino]

I can imagine 84 mph with this chainring.

[Mark McM]

Originally Posted by tuscanyswe

So does everyone use supershort cranks in these events? Are they limited even?

This is getting far off the original subject, but yes, some people use various bike modifications for roller racing. The USCF sets a maximum gear size, and rollers have only a small amount of resistance, so roller racing speed largely comes down to how fast you can spin the cranks. Shorter cranks and a lower saddle makes it easier to spin the cranks fast.

On the flip side, since an e-bike modified with this Gizmo can still apply a power boost above the normal limiting speed, what's to keep people from putting a bigger gear (larger chainrings) on the bike to go faster? Since the Specialized Creo has a normal power assist speed limit of 28 mph, the Gizmo will increase the power assist speed limit by a factor of 3 to 84 mph. If you replace the 46 tooth chainring the bike comes with for a 53 it means that you can go 34 mph at a modest 90 rpm. Since 34 mph is well below the modified 84 mph speed limit, you can probably still get the full 240 Watts of boost at this speed. At 100 rpm you'd be going 37 mph. Sure, it takes exponentially more power to go faster, but with 240 Watts of boost (double my FTP) I could cruise at 30 mph on flat roads on this thing, and faster on moderate down slopes.

[Waldo62]

Snip:

Originally Posted by Steve in SLO

Clever idea. Love this section of the website:

TERMS & CONDITIONS

Legal stuff

Since there are still people out there that can't be expected to function in the real world and "Starbucks hot coffee" lawsuits are not a thing of the past, let's clear up a few things regarding PLANET3...

McDonald's hot coffee lawsuits...