bbs02 e-cyclocross?

[LiFeCycle]

Hi All

First time here. I've enjoyed spending some time over the christmas break on this forum reading about the different motors, batteries, bms's, CAs, etc you can put on a bike. Coming to this forum was kind of like discovering wikipedia for the first time.

I already commute on a road bike, so i get 30km a day of riding. Pretty happy with that. The electric bike concept appeals because of the possibility of extending my range and replacing the car for some of the longer trips.

Kepler's super commuter was the build that inspired me to take on a build of my own. I'm interested in something lightweight where i contribute a meaningful amount of power to the bike.

So I've chosen to do a bbs02 cyclocross bike, with 48v11.6ah (4p13s panasonic 18650s) bottle battery from bmsbattery. A $2.30 ebay usb ttl converter to wire it up and properly program it. I am so pleased that it's possible to set speed to 100% on the low current settings, because that is how i will use it, on low boost at high speed.

Here is the bike i'll use. It's 2013, shim 105 groupset. One of the main reason's I like middrive is that i don't have to downgrade the drivetrain. And the ease of changing flats.

My only concern is that the cyclocross platform seems to be an unusual choice amoung the builds i've seen here, with most opting for front suspension and flat bars. It seems odd to me - I much prefer the aerodynamics and multiple hand positions of a road bike, and I would have thought that only gets more important the higher your speed gets. I would just get uncomfortable riding a flat bar bike more than 20km. Is there a particular reason why no-one does e-road bikes with drop bars?

Looking fwd to participating in the ebike discussion/revolution

 

[Raged]

It's more versatility... wanted to build a cyclocross, but

- the cost of entry was too high (shimano 105 or ultegra groupset) would start at $800... whereas a nice hardtail mtb was 1/2 the price or less.
- durability of frames aren't known. With an MTB you know you can throw it at a tree and it will still be ok (mostly).
- rear dropouts are stronger on an mtb if you get a hub which is where most people start.
- fat tires are needed for the extra suspension and grip to handle the weight of a motor and battery pack while travelling (so small issues in the road won't bounce you). Also with fatter tires, your stopping distance/grip in the wet is greatly improved.
- Drops == mostly pedal assist. Flat bar you can mount throttles easier.

I went 1/2 way and got a 29er. I can fit 29" MTB tires for trail.... or 28" big apples for fat road balloons... or even skinnier 700c35 as the rim profile is the same. It has a flat bar for throttle (I run a rear hub) and hydraulic brakes is pretty much essential for anything over sustained 50kmh in all weather conditions. Just lock the front fork and it's a competent road weapon.

Only disadvantage is geometry of mtb trail vs road aero. But that depends on what you're used to.

 

[mfj197]

Welcome LiFeCycle, good to have you around.

I think the main reason you don't see commercial e-road bikes with drop bars is that at least here in Europe the speed limit on electric assist is 15.5mph. Most roadies will cruise over this speed anyway, so why would they look at an electric assist that would just add weight. The benefit of drops would only be felt at speeds over and above the assist speed. The (legal) ebike market therefore caters for cyclists who are used to more sit-up-and-beg style bicycles.

There are other small reasons, such as inability to use a throttle on drop handlebars (not that that bothers me). That's about it though. In many ways a cyclocross bike makes an ideal candidate for conversion, and I've looked at them as a solution for my commute too (44 mile round trip). In the end I've just bought a flat bar road bike for a slightly more upright position and with lots of tyre clearance for wider slicks. Picked it up yesterday, and I have a BBS01 to put on it.

Michael

 

[LiFeCycle]

Hi raged. Yes, that would make sense that an mtb frame would be more durable. For me I'm a 65kg rider, motor+batt ~10kg, I'm thinking cyclocross should be sufficient. It's supposedly stronger than a road bike frame.

Thanks Michael. I had trouble believing that 25kph was the limit too, i thought it must surely be a typo of 25mph. Makes sense then why no road riders are interested.

Yeah, I'm hoping that it will be the ideal platform, for my riding style at least. No worries about the throttle once the PAS is tuned right, but i'll have a thumb throttle anyway, because i'm quite happy to ride on the tops. There is even an extra set of brakes there on this bike

Best of luck with your bbs01 build too.

 

[leo99]

Hi lifecycle,
You might want to check out for some ebrake cut off since your are going to be riding in pas. I know em3ev sells cutoffs that are connected to the cable of your brakes so that you can keep your curent brake set up and they are plug and play
It's going to be a nice set up. I almost did the same but the price and my bad road made me change my mind

 

[LiFeCycle]

hi Leo99, that's a great idea on the brake cutoffs, thanks. Another thing I was thinking which I'm not sure if it's actually possible or not, but seems like it would be useful based on others experience of the bbs02, would be a throttle cutout for shifting. Ideally, it would be a microswitch on the shifters, which would cut out the motor after you moved the shifters a millimeter or so, allowing for a shift under no load, and a quick startup again after the shift.

I'm not sure if anyone's come across such a device for the 105 style shifters?

 

[Melbourne]

hi life

There is a store in Oz that sell bbs02 and i brought from him..all good.
http://www.emax-ebikes.com.au/store/c1/Featured_Products.html

 

[leo99]

H life i don t believe there is any shifters cut off pulg and play for 105 but again em3ev has some cut off systeme where you can put a magnet and when it is to far from the rest it cut offs the motor
It is already the good plugs. I would have sent you the link but my phone is not working properly

 

[LiFeCycle]

Good to know, Melbourne. I wish I had known that before i bought! It was AU$1198 for the kit and batt from bmsbattery, could have got the same thing from emax for 1150. Next time.

 

[LiFeCycle]

Update: The cyclocross had cable disc brakes, and the stopping power was so much less than my road bike with calipers, that i felt unsafe riding it even unassisted.

So, I fell back to the mtb plan. The parts arrived on friday, spent friday evening and saturday doing it, and here it is!

It was so much fun building it, and I finally know how a bottom bracket works. I would definitely recommend the BBS02 kit as a great kit that a non-mechanically minded person can easily install. I didn't have to do any chopping or resizing of any of the components, didn't have to drill any new holes anywhere or custom make any brackets to mount everything to the bicycle.

The 'bottle-09' bottle battery bolted straight into position with no fuss. The connection to the battery, is as simple as soldering the black and red wires from the motor into the battery mounting thing, which all unscrews for easy access.

All in all, a plug and play kit. The kit was $1100, and the bike $700, a multi tool kit $65 so well under $2k, for something that i reckon rides better than a stealth fighter.

Without endless-sphere, this bike would not have happened. Thankyou!

 

[LiFeCycle]

Oh, i will be putting big apples on it soon too, and reprogramming once the usb ttl arrives. But even with the knobbly mtb tyres it has at the moment, it is no trouble getting to 45kmh. Looking fwd to see what it can do on slicks.

 

[d8veh]

I've tried a BBS01 that had brake cut-outs on the shifters. I couldn't quite see what the guy had done because it was so neatly done, but I think it was a reed switch and magnet. They definitely cut the motor when changing gear, but it still didn't seem to solve the problem. There was still a bit of a bang when changing down going up hills. I think it needed a longer delay because the motor was giving power before the gear had changed.

I've also tried a Kalkhoff that has factory fitted switches on the gear-change. Again, it was better than some others, but not a complete solution.

If you try it, let us know how it goes.