#### Ravi Kempaiah

##### Well-Known Member

Next year, they will be releasing a 48V, 24Ah pack for the hybrid styled Cross Current. Holy molly...!

More info can be found here

**(Link Removed - No Longer Exists)**

**(Link Removed - No Longer Exists)**

- Thread starter Ravi Kempaiah
- Start date

Next year, they will be releasing a 48V, 24Ah pack for the hybrid styled Cross Current. Holy molly...!

More info can be found here

I could get into something like this! ...

I don't know. The equation for power needed to propel a bike at a certain speed is mostly calculating the aerodynamic drag, which rises by 4x as speed doubles. At 28 mph, the power is around 750 watts. The speed pedelecs that Haibike is going to sell seem to have 350 watt motors. If you have 350 watts available, I'm not sure how they will get the 750 watts they need to go at the SP limit. Not too many riders can supply 400 watts for very long. A race frame would help.Ummm, folks, it's still a 350 watt hub motor, no matter what the windings but with a nice battery. A 350 watt mid drive produces more torque and power than this hub motor so its not a one-to-one match with the Izip Dash.

When someone says they are designing a 30 mph bike, it makes a lot of sense to use a 1,000 watt motor. That is what Bafang is offering, a 1,000 watt mid-drive. It would be very easy, and pretty cheap, for JR to provide a 750 watt motor. Several things on their web page for this bike need fact checking.

At some point I think you need hydraulic disks. If you need a lot of watts to get to a high speed, you need a lot of braking power to slow down.

But, if Juiced Riders bumped the rear hub to 750 watts and their brakes are solid, their tires and wheels sturdy and reliable, etc, they have a 28 mph bike that is reasonably engineered for a very decent price. You don't need fancy electronics to make a bike that will hold up for, say, 5,000 or 10,000 without major overhauls. What do you need, if you are now going 28 mph? Does anyone know? It's unfortunate that a lot of the people with 2,000 watts and 35 mph capabilities are relatively inexperienced with bikes and bike weaknesses. Maybe there is a glaring fault with what JR is doing. Certainly Court or Ravi could do an evaluation. Why do I feel something like this would make more sense?

It would be fun to know which design path is better. Do you want a basic mid-drive like the Curry, which will probably do well on hills? Do you want motors with the raw watts to go faster? A 20 mph bike is around a 350 watt bike, but getting to 28 mph doubles the power requirement.

Good point about the maintenance on the hydraulic disc brakes, Ann. There's certainly a trade-off there. My S-pedelec with mechanical disc brakes is screaming for a set of beefier hydraulic discs, and it seems like all the s-pedelecs are going hydraulic because customers want that stronger braking feel.

Regarding the 350W Bafang geared hub motor, keep in mind that because the Juiced Riders CrossCurrent has a geared hub motor, it will likely be very zippy up hills even though it's not a mid-drive. A direct drive hub motor like the 2015 E3 Dash doesn't have the mechanical advantage/leverage that comes with either a mid drive (using the rear derailleur's gearing) or the hub motor gears, but this bike does. We'll have to see how it compares against the 2015 Dash with a battery of tests.

Good point about power requirements. I've often wondered how those Bosch S-pedelecs hit 28mph. I'm not certain, but I think that you don't need as much power to get to those speeds. I think 400W-500W would suffice to reach 28mph with some average pedal input, and that's quite doable with a 350W (nominal) motor. My 500W (nominal), 750W (peak) rear hub motor bike can hit 32-34MPH on flat ground with heavy pedal input and a low, aerodynamic body position, but if I were using your assumptions about power and speed, then I would need 1,000W+ to hit those speeds, and I just don't think my bike has that much power, even at peak output. Perhaps there are more variables here that complicate things...perhaps my aero body positioning gives me more speed that isn't factored into your power/speed model. And I'm also pedaling quite hard to reach those speeds, and one cannot maintain that forever.The equation for power needed to propel a bike at a certain speed is mostly calculating the aerodynamic drag, which rises by 4x as speed doubles. At 28 mph, the power is around 750 watts. The speed pedelecs that Haibike is going to sell seem to have 350 watt motors. If you have 350 watts available, I'm not sure how they will get the 750 watts they need to go at the SP limit. Not too many riders can supply 400 watts for very long. A race frame would help.

When someone says they are designing a 30 mph bike, it makes a lot of sense to use a 1,000 watt motor. That is what Bafang is offering, a 1,000 watt mid-drive. It would be very easy, and pretty cheap, for JR to provide a 750 watt motor. Several things on their web page for this bike need fact checking.

It would be fun to know which design path is better. Do you want a basic mid-drive like the Curry, which will probably do well on hills? Do you want motors with the raw watts to go faster? A 20 mph bike is around a 350 watt bike, but getting to 28 mph doubles the power requirement.

A mid-drive produces more torque for better hill climbing since you can use the bike's transmission, but has some drawbacks at the moment for the scope of the CrossCurrent's objectives. In exchange for pulling trailers and flying up steep hills, the CrossCurrent returns you a relatively light bike for assisting you at 24-30mph comfortably.

Hi,

A mid-drive produces more torque for better hill climbing since you can use the bike's transmission, but has some drawbacks at the moment for the scope of the CrossCurrent's objectives. In exchange for pulling trailers and flying up steep hills, the CrossCurrent returns you a relatively light bike for assisting you at 24-30mph comfortably.

I can see that. I have a '350 watt' MAC motor, but I get 800-900 watts out of it on hills all the time, using a watt meter. It's like you say, the controller has to be able to put the watts into the motor, and the battery has to have the discharge rate. We'd all be better off with 'real world' watt numbers from the specific battery and controller. Thanks for clearing that up. I think this bike has a lot of potential.

@Cameron Newland -- I'm using a very rough aero drag calculator based on an upright bike with MTB tires. Actually, if you can put 300 watts into the drivetrain, you could hit 30 with a 500 watt motor that peaked a little higher. The details are things like efficiency of the motor. I wish they put watt meters on bikes. It's very educational. As long as this bike is closer to 500 watts, they are in the ball park for a good 'theoretical' speed, just based on a fit rider adding 200 watts to the mix.

Sorry for the video but trying to do this with one hand pedaling and changing gears.

It's easy to make out the numbers if you pause the video. It was clearly running around 27 mph with over 600 watts going through the system at the start. So the Bafang is capable of delivering what you need for that Class 3 California standard.

Sorry for the video but trying to do this with one hand pedaling and changing gears.

The price seems fair. You could do what I did, buy a $400 Bikes Direct bike. Then buy a 350 watt MAC motor and controller for around $400. The battery I use is primitive, a LiFePo, for around $300. I had to replace a couple of things on the installation, and I have mechanical disk brakes. I would have looked at your bike, for sure. I think you are locked into the California rules for Speed Pedelec, where you can't have a throttle. I notice a lot of attention to detail on the web page, and a commitment to parts and service, plus the two year warranty. JR has refined the original bike over and over. People with limited experience seem to run into quality control problems. Hopefully JR can avoid that stuff.

If the 7.8 ahr /48V pack is 5lb, the 23 ahr will add 10 lbs and won't look as slick. Just sayin'.

Next year, they will be releasing a 48V, 24Ah pack for the hybrid styled Cross Current. Holy molly...!

More info can be found here

(Link Removed - No Longer Exists)

(Link Removed - No Longer Exists)

An 1100 Whr pack can do some major range! Or juice up the motor a bit to 750W continuous and you have a nice speed pedelec.