kmcrawford111

Hello everyone, I am strongly considering converting one of my bikes to electric drive. Since this is a considerable expense, I'd like to know what might work best in the opinions of people with experience. Any help will be very much appreciated.

Background: I have been a regular, unassisted year-round bike commuter for 6 years. Previously my commute was about 7 miles each way and I had no problem doing it daily. Now my commute is about 17 hillier miles each way and and I've decided that I'd like some help. My plan is to generally alternate days between riding the road bike and riding the converted ebike. Essentially I'd like to replace the driving I'm doing now (about half of the total miles) with assisted biking. I weigh about 190 lbs. and would like to use the assisted rides for transporting perhaps 5 lbs of stuff to work, mostly food, so the return trips will generally be lighter. Charging at work is not a problem, and preferred.

According to my Cyclometer app, these are the total ascents / descents, in ft:
To work: 590 / 322
To home: 627 / 354

Bike: The bike I'll likely convert is a Swobo Dixon, the earlier model. It has more MTB-like geometry and an internally-geared SRAM iMotion-9 hub. It is a pretty sturdy aluminum bike with disc brakes. It has a single chainring and 135mm rear dropout spacing. I know that any rear motor will mean getting rid of the IGH, but I'm OK with that. (Is there any reason a rear-wheel conversion won't work on this bike if the IGH is removed?). The wheels are 26".

What I'm after: I want to give my legs a break every other day. I'll get a sufficient amount of exercise every other day on the road bike without assist. I want a high level of assist. I want the rides to be easy. In the interest of saving time, I want the ride to be fast. 20 MPH or faster on flats would be nice. I am willing to spend what it takes to have these requirements met. I don't want to be dissapointed, but I would also like the system to not be heavier than needed. I would like a system that can handle being rained on, and that can be used in the winter, at least down to 20 degrees F. I want real world battery capacities. I don't want the battery to be adequate for my needs for just a few months before needing replacement.

For a long time I was considering the eZee front wheel kit. I like that it doesn't lock users into batteries as BionX does. I like the idea of the simple installation it would entail. What I don't like is the lack of proportional assist (like BionX has) without adding components and the strictly-rear battery mount. Even with only a rack and empty basket in the rear, this bike feels too unstable. Then again, the heavier hub motor would probably help balance this out.

More recently I was intrigued by the PL 250 Bionix kit. It's $1000, which is easy to swallow. It's got proportional assist, and it's got the downtube-mounted battery, which I like a lot. I also like the regen. But this kit looks to be lacking in power for my purpose from what I've read. Agree/disagree?

So I'm considering a more powerful BionX kit. Or maybe the eZee again. It's hard to decide without first-hand experience.

Finally, do standard freewheels work with eZee or are the freewheels unique? Because if I do a rear conversion, I need a single-speed freewheel.

Thank youm very much.

EBikeFL 

Hello, kmcrawford111.

I would use the Papamotor 48v 1000w rear wheel kit which I've documented here: https://www.bikeforums.net/showthread...onversion-kits

If you're not afraid of building your own wheels then I would just purchase the Papamotor 48v 1000w rear hub motor and use Sapim race spokes and nipples to make a bullet proof bottom end.

Purchase the other items from ebike.ca and get a Lyen controller. The 12 FET 4110 MOSFET Extreme Modder Controller Lyen Edition works great.

Use two Ping 48v 15Ah batteries and use the "Y" splitter from ebike.ca to connect them to the controller. You can use Bikebins to hold everything and keep things waterproof and secure.

Oh, when you realize you don't need to use your car at all with the above setup; you can thank me with a percentage of the proceeds from the sale of your car.

350htrr

The PL 250 BioniX would not work for you unless you can charge it at work, a 350 48v set up would work for you without needing a charge half way, but is way more expensive...

kmcrawford111

Thanks - I am able to and prefer to charge at work. It could only help make the batteries I need to have smaller.

knurly

I'm not sure how to translate your ascents / descents numbers. I happen to reside in central Oregon where every road goes up or down. I have a Bionx 350. It gets hot on hills and cuts out, I'm pushing the bike at times until things cool off. But then, I would never consider biking my hills if it were a daily commute. You'll probly be ok, but we all wish for more power & speed, battery capacity, a gyrocopter...

350htrr

Wow, they must be some hills, I have gone up some big hills around here and mine has never cut out even on level 4 all the way... Have you tried the mountain mode/hill feature?

kmcrawford111

If the BionX PL 250 kit really would come close to fitting the bill, I'd like to know more.

350htrr

The only way to be sure is to try it if you can take the bike for the day... Everyones pedaling capacity is different, my 10% pedaling effort could be 50% for someone else or viceversa... From your expetctations in your 1st post the 250 would/could be not quite enough, you said lots of assist as you want the rides to be easy, and real world battery capacity sufficient so you don't run out of juice Having said that if you can charge it both ways than maybe it can meet your expectations... Tho even the 350 would be borderline without a charge midway if you want high levels of assist like 3 & 4, 1 and 2 could make it all the way there and back... JMO

knurly

Yeah but, if you can get up to 20mph you notice the assist tapering back. I don't know how there can be any difference in range at any level if you can get on top of the assist curve.

350htrr

That's true, once you get to 32KMs/20MPH the assist cuts back and if you pedal enough to keep it there, it wouldn't matter what level 1,2,3,4 assist you have it on, but if you want to keep it there without pedaling, or pedaling much, you have to use the throttle or have it on the higher levels to keep it there with minimal pedaling... At least that is my understanding/experiance of how it would work...

kmcrawford111

20 MPH is fast for me. I average about 16 MPH on my road bike, and it's certainly less on this bike. I consider myself a consistent rider more than a fast rider.

I do very much like the price on the BionX PL 250... enough that I'd consider putting in more effort to make it work. If the motor did about half the work I'd be pretty satisfied.

I understand this is difficult to figure out with the 20 MPH cut-off. I very much appreciate all the help.

350htrr

The PL 250 can go 40 miles on 1 charge on level 1... So it "can" do the job with just 1 charge, but it's only 25% help. As soon as you start to use more than level 1, then you will have to charge it before going to work and charge it again at work before going home... JMO If that's OK with you it should work out...

kmcrawford111

Thanks so much again. Do you have an idea about the highest assist level I could expect to be able to use for the whole commute if I regularly fully recharge at work? I would like level 3, but I'm willing to consider level 2, considering the price of the kit. $999 at NYCEwheels with the Gen 1 console. Is it safe to assume that since level 2 is twice the assist of level 1, it uses twice the battery charge, and so on through level 4? The assisted steps are listed as 25, 50, 100, and 200%. Then again, as someone else stated, the assist cuts out at 20 MPH so perhaps the battery usage is less than double at say level 3 vs level 2 since at the higher speeds the assist generally would mot be active as much?

Also, any idea of how well the system would work with a single-speed freewheel?
Since the bike is IGH I would have to use a SS freewheel. I don't know if it's even possible to add a rear deraillieur, but I like the idea of the SS anyway - having just one speed adjustment (the assist level) to think about. I just hope the pedalling works OK with the assistance since I'll be stuck at one unassisted speed. The current cog on the IGH is 20-tooth and I know how the drive is there since IGH speed 5 is a 1:1 gear ratio. I'm thinking that with BionX I might want to start with 22 teeth to compensate for the additional weight. One nice thing about this setup would be that it wouldn't be terribly heavier since the IGH is heavy itself and would be removed in the process.

350htrr

I would say that level 1 is the highest setting that the 250 would make the trip both ways on one charge if you use it 90%+ of the time, sure if you only use it 10% or less of the time then you could use it on level 3 or 4 for just the hills, but then you would be pedaling harder than you say you really want to for the rest of the time... EDIT; seems like this set up just misses the mark as to what you really want/need. JMO

chas58

It won't work. Not unless you get the chain line perfect. If not, the chain will just fall off. Go to the SS/FG area if you want more people's opinion on how to do this. Also, how will you keep the chain taunt - running an idler wheel?

Bafang CST is the only one that I know of that will take the regular shimano mountain bike cassette. Otherwise, you are typically looking at a 6 or 7 speed freewheel.

If you can get the chainline and chain tension addressed, it could work, but it is likely to be a headache getting the chainline right, unless you have a lot of flexibility in placing the cog. You could get a Bafang CST, and then a single speed adapter kit where you can place the cog anywhere on the spindle, then add an idler wheel for chain tension.

You get that chainline just a little off, and the chain will pop off. You could get the drawings of the motor and take some close measurements and then cross your fingers...

kmcrawford111

Thanks for the reply and the information.

I would keep the chain tensioned the way I already do - by sliding the rear wheel further back in the horizontal dropouts as needed (as the chain wears). I can also slide the whole disc brake back with it if needed - there are slots around the mounting screws for this. It is a little surprising to me how often this needs to be done even when replacing the chain at 1% stretch, but at least there's a relatively easy way to do it. I would also use a cog with tall, un-ramped teeth to help keep the chain on.

The chainline is more problematic. I hadn't thought about it too deeply, but I was thinking that since there's obviously enough room for a multi-speed freewheel, there should be plenty of room for a single-speed freewheel. The problem I realize thanks to your post is that there seems to be a strong likelihood there won't be enough length on the threaded section of the hub to fit both the SS freewheel and whatever spacers I would need between the hub and the freewheel. Currently the freewheel on the IGH is close to the stays similar to the smallest cog on a derauillier bike, so I'd have to come out quite a bit. Probably way too much.

I can see how this wouldn't be a problem with a Freehub - the section the cogs fit on is much longer than the shorter threaded section of a freewheel hub. All this raises the question: why do most motor hubs use freewheels? Haven't Freehubs been the prevailing standard for some time now?

Maybe a front kit would be best - but I still like the pedalec, downtube battery, and price of the BionX PL 250 kit.

How is this Bafang CST motor? I'm able and willing to build my own wheel, and even already have a complete extra wheel for this bike I can use parts from.

Once again, thank you. All this help is very much appreciated.

chvid

An additional issue with freewheels is that there are only low quality DNP ones available (from ebikes.ca) which have 11 teeth on the smallest cog. This is desirable to get up the gearing sufficiently high to be able to assist meaningfully at top speed by continuing to pedal. Shimano doesn't make 11 teeth freewheels anymore. As noted, almost all hub motors use screw on freewheels, except the CST Bafang.

swngdncr

I'm having the same probem as knurly. My first BionX motor died after 6 months and was replace. The second motor is 2 years old and can no longer manage a sustained climb of 5-10 minutes depending on the assist level. I sent it to Nyce,who sent it to BionX. They tested it for 20 minutes, said it was OK, and sent it back 3 months later without making any repairs. Its a long story, but they are now telling me that the motor isn't capbable of climbing for 5 minutes, that I am asking too much. I'm looking at the new Cycle Analyst system that ebikes is offering. Looks like a much better system in many ways.Also, the bionX starts to throttle back assist at about 15mph. That is a problem on mild descnts, flats with a tailwind, I can't stay with my husbandbecause I'm pusing 60lbs of bike pretty much on my own.

350htrr

What REV (revision) do you guys have on your controller? Does it have a MOUNTAIN mode? Mine has a mountain mode that you can get at, after level 4. I have REV 59 on my controller and have gone up 12% gradients 1 mile long, with no problem, and the total weight of bike, me, and my stuff is like 275Lbs... EDIT; Doesn't your BionX have a throttle swngdncr that when you engage, it just takes you up to 32 KMs/20MPH regardless of what level you have set, so that you could keep up? EDIT no 2; I just thought of why your electric motor may not be putting out as much power as it used to, if you have removed the rear wheel for any repairs it may not have been put back properly as the torque notch on the axle needs to be at the 6 o'clock position to sense the applied torque from the pedals..

CaliforniaEbike

Hello kmcrawford111,
At first glance, I would opt for motorizing the front wheel and saving the internally-geared SRAM on the back wheel. Probably a 750 to 1000 watt 48 volt direct drive. The only concern I would have is the aluminum forks. We don't normally recommend using the high power hubs on aluminum but as long as they are not cast aluminum you probably are OK. If your going to make the electric hub do most of the work however, from what you describe, your going to need a good sized battery probably around 20Ah with a 5c rate. A battery of this size will probably have to be mounted on the rear rack and motorizing the front wheel will balance out the load. I have included a link that will provide basic information to help you make a selection https://california-ebike.com/ebike-co...kit-selection/
Our standard battery (10 Ah) will, on average get about 17-18 miles between charges with lite pedaling but that puts you on the fringe and is not recommended for your ride and elevation variations. I would also recommend the Lyen controller with regen and top it off with a Cycle Analyst setup to properly monitor your system.

chas58

kmcrawford111

That Bafang CST is a great motor. It may be perfect for what you need (you just have to figure out which motor code you need).

If you want to be single speed, you can use a single speed cog on it, with the appropriate spacers to put the cog in whatever chainline you need. That is roughly what I did on a non-electric conversion like that. I just don’t know how you can adjust the chainline if you use a screw on cassette.

Why do the motors use an old design screw on cassette? Well most of them are manufactured, bought, and sold in China.

Personally I wouldn’t put a front motor over 250watt on their unless you have a steel fork. Any kind of shock loading with torque will snap off those light alloy fork ends.

kmcrawford111

Thank you both. California EBiker, your chart is very helpful. I'm leaning towards a front wheel conversion now... If I leave the IGH in the bike will be pretty heavy, but I'll be able to convert back to regular bike mode in the winter, when I've been using studded tires on this bike.