Make sure to take careful measurements before ordering if you go this route. Might not be bad to swap as long as. It’s not regularly. You might want to eventually no power both bikes and just swap the battery back and forth.
Hill Climbing Assistance
- Thread starter metanewbie
- Start date
docw009
1 MW
The 2023 BBS02B model I bought/installed last year for a friend certainly had awful pedal response. Each assist level had a certain motor power and a cut-off speed limit. Exceed it and the motor shut off, Fortunately, one could buy a program cable and change that awkward setup. I have an older version that is set up well.
I don't find the BBS02 has much drag when motor is off, but the bike is a big part of that. If your bike didn't roll well when it was a bike, it's not going to be much fun with 20 more pounds of motor/battery.
wturber
1 MW
It's hard to tell based on the graph - what is the grade percent on that one very steep incline (big drop on the graph)?
IMO, once you start riding with some assist, you'll end up wanting to use it more. You'll enjoy getting to work a bit quicker. You'll find you can still pedal at a good effort while using some assist.
I agree that "on paper" the QiRoll looks appealing. But I'm pretty sure that "in practice" a more conventional approach will be better. That said, there is no conventional approach that lets you switch between both bikes. At best, you could move the battery back and forth. Also, adding a motor wheel will change the way the bikes feel. So the suggestion to get an inexpensive base bike as a starting point is a good suggestion IMO. At least it is if you really like the way either of the two other bikes ride and feel right now. Of course, you could convert the hybrid you have, and if you are unhappy with the way it feels after the change you can always remove the ebike components and then put them on a suitable third bike.
wturber
1 MW
I buy from them as well and agree with Chalo's assessment.
You want a small boost up hills but the problem is, these little motors aren't often geared for hill climbing.
Many of them will overheat
Geared hub motors come with all kinds of different gearings and also different windings. With a geared motor you can optimize for mostly flat ground, or in your case, mega hills.
The other option is a mid drive if you are looking for low weight.
ebike4healthandfitness
100 kW
- Joined
- May 19, 2012
- Messages
- 1,143
A 5T version of the GRIN Bafang wheelbarrow motor would beat any geared hub motor on a climb (even Bafang G62) according to the ebikes.ca motor simulator.
metanewbie
100 mW
If I go with mid drive can I use my current drivetrain?
Advent Supershort RD with clutch 1 x 9 Raceface narrowide 30T chainring Advent 11-38 cassette.
Advent Supershort RD with clutch 1 x 9 Raceface narrowide 30T chainring Advent 11-38 cassette.
Depends on the mid drive, look for compatibility with a 9-10 speed chain.
You may need to switch to 8 speed with the cheaper ones.
Expensive ones built around being very bike compatible ( lightest,bike, revel propulsion ) should work with any drivetrain. But you're going to pay ~$1k for one.
Mid drives can get expensive and are less reliable
But it'd be not great on the flat efficiency wise due to the extreme gearing.. this setup has also not been tried and requires mechanical work, not a good recommend for a newbie
You may need to switch to 8 speed with the cheaper ones.
Expensive ones built around being very bike compatible ( lightest,bike, revel propulsion ) should work with any drivetrain. But you're going to pay ~$1k for one.
Mid drives can get expensive and are less reliable
But it'd be not great on the flat efficiency wise due to the extreme gearing.. this setup has also not been tried and requires mechanical work, not a good recommend for a newbie
metanewbie
100 mW
Is there anything I can setup for a grand total of less than $500-$600 with battery?
ebike4healthandfitness
100 kW
- Joined
- May 19, 2012
- Messages
- 1,143
The stock wheelbarrow motor is 10T winding, but 5T would actually give great efficiency on the flat according to the simulator:
Very impressed with the implementation of the gear reduction on the Bafang wheelbarrow motor vs. Bafang G310 (both hubs use the same 10T motor core)
Both hubs use the same Bafang 10T motor core but the according to the ebikes.ca motor simulator the 11:1 two stage planetary reduction on the Bafang G310 yields a peak efficiency of 81.9% while the 30:1 two stage internal jackshaft reduction of the Bafang wheelbarrow motor yields a peak...
endless-sphere.com
Not anything good, even a low end mid drive will cost ya $400.. em3ev battery.. another $400ish..
You can get a random chinese geared motor kit w/o battery for $200 shipped.. but.. it won't be geared right.. it won't be tunable.. it won't be efficient.. so it will probably overheat on your big hill climb.
You have high grade climbing requirements. Luckily you don't weigh much. .. so you don't need a huge motor but you do need the right motor.
The stock wheelbarrow motor is 10T winding, but 5T would actually give great efficiency on the flat according to the simulator:
Very impressed with the implementation of the gear reduction on the Bafang wheelbarrow motor vs. Bafang G310 (both hubs use the same 10T motor core)
Both hubs use the same Bafang 10T motor core but the according to the ebikes.ca motor simulator the 11:1 two stage planetary reduction on the Bafang G310 yields a peak efficiency of 81.9% while the 30:1 two stage internal jackshaft reduction of the Bafang wheelbarrow motor yields a peak...
Motor Simulator - Tools
79,5% efficiency is not very good compared to the 86% efficiency on the flat scenario was describing that would adequately climb the hill. You also need a 72 volt battery to hit 19mph, so this will require a specialized controller.
The motor still needs physical modification, you haven't done these modifications or tested them, nobody else has either. Without doing this previously, you don't know if the parts fit. Please don't send newbies on a wild goose chase with theoretical unproven setups. You're doing them a disservice by doing so.
metanewbie
100 mW
So, realistically, I'm looking at roughly $800 minimum. Is that correct?
ebike4healthandfitness
100 kW
- Joined
- May 19, 2012
- Messages
- 1,143
I bring this up not because I expect anyone to do the huge amount of work rewinding a 10T motor to a 5T motor then on top of that making a hubshell for it appropriate to building a spoked motor. That is not reasonable by any stretch of the imagination. I am merely bringing this up because you claim existing geared hub motors are not good at climbing which I do agree is true.
A 5T version of the wheelbarrow motor converted into a proper ebike motor would be one way to approach this problem.
Last edited:
ebike4healthandfitness
100 kW
- Joined
- May 19, 2012
- Messages
- 1,143
Not with a 5T winding. With a 5T winding you only need 52v to hit 26.2 mph at 86.5% efficiency. (see post #35 --> Hill Climbing Assistance )
Ok, OP is looking to buy a motor for his first ebike, not engineer one.
Yep.
You want really cheap? buy a semi broken ebike and fix it.. tons of ebikes out there need literally just a new controller, screen, and throttle.
ebike4healthandfitness
100 kW
- Joined
- May 19, 2012
- Messages
- 1,143
Agreed. We need the ebike industry to engineer better hub motors so we can choose from better ready made products.
Unfortunately the world of hub motors is currently in the stone age compared to mid drives.
I mean seriously we don't even have IPM inrunners in hub motors yet.
metanewbie
100 mW
Ooh, that's an interesting idea. Or cannibalize the parts for my own bicycle. I love the feel of my bike.
offGridDownUnder
1 kW
They have to fit. Many ebikes have some proprietary part or another, and good luck engineering it together. You might get lucky, but you'll need to buy the junker to find out, and you're out the money without any recourse.
Batteries in particular are generally the single most expensive part and some of the proprietary ebikes will not accept a battery unless it sends the right signal - this is a deliberate action by the manufacturer to keep selling batteries and avoid the expense of supporting some random replacement they didn't design. It's both greedy and sensible for the manufacturer.
If you buy a junker with generic parts that you can swap out (some manufacturers do this too) you're left with the problem of 'why did it break?'
Are you in a position to make novel parts from scratch? From what materials? Many are, and I think this is great, but it's a question for you.
I can say there is one principle that applies when attempting to substitute my time and attention for money and certainty when pursuing a goal - I'd better have a lot of time and attention, and no one is going to do it for me.
Yes, I can imagine it all 'just working out' and 'first time!' - but that rarely happens if I stray from standards. In return for lengthy hassles pursing problems if I choose to persist I can emerge eventually with hard-won knowledge and experience. The cost is the 'lengthy' part and the 'uncertain' part.
There are very good reasons we gather in groups and work together and learn from each others - it costs quite a bit less to learn from someone's success than it does to work it all out from scratch ourselves. Every time.
As I move into retirement, I may take on learning more deeply by hacking into random ebike systems (among other topics), but in setting up my own, I have deliberately chosen to go with the best quality parts I can find that aren't strictly proprietary. In addition to being DIY focused, Grin has also shown that they are engineers who aren't trying to franchise and get rich - they are enthusiasts who want money to build more electric vehicles for humans. I feel very fortunate they are in the market, and I am happily paying them to keep on doing this as that's the best guarantee I can find.
My point is not that Grin is wonderful, my point is that they represent the best example I know of "you will get what you pay for". They happen to be a terrific resource to have. If you think from that perspective, you can evaluate what you really want and decide if they "cost too much". In my case, no. In your case, maybe yes.
You may not have as long a time horizon as I do, and you may also want to dive into learning the deep secrets of ebikes. I'm designing for 20 years (I know I can't rely on this, but I am - it helps me make choices).
Last edited:
metanewbie
100 mW
I see what you mean. I've only been browsing customized DIY ebikes for sale for that reason.
Yeah prebuilt bikes.. if they come with mid drives.. all have proprietary mid drives..
If they come with a hub motor, things might be interchangeable.
99% of systems have 3 phase motors with hall sensors, so if they have broken electronics, the entire set of them can be replaced,
Cheaper prebuilt ebikes often have batteries that don't have these artificial protections baked into them, therefore the motor and battery can be used, you just need a controller with the appropriate accessories.
I only mentioned it because you're looking for cheap and i'm trying to help you avoid buying some crap ( that's what most people do when they're new, then their first posts here, are )
I would certainly chose to build from scratch instead. I also like what i like about my bikes. DIY can be so much better than stock
If they come with a hub motor, things might be interchangeable.
99% of systems have 3 phase motors with hall sensors, so if they have broken electronics, the entire set of them can be replaced,
Cheaper prebuilt ebikes often have batteries that don't have these artificial protections baked into them, therefore the motor and battery can be used, you just need a controller with the appropriate accessories.
I only mentioned it because you're looking for cheap and i'm trying to help you avoid buying some crap ( that's what most people do when they're new, then their first posts here, are )
I would certainly chose to build from scratch instead. I also like what i like about my bikes. DIY can be so much better than stock
ebike4healthandfitness
100 kW
- Joined
- May 19, 2012
- Messages
- 1,143
Some of them will also have burned up motors (re: the cheap pre-builts lack temperature sensors) so be careful what you buy.
With that noted we are at a time when "race to the bottom" is so strong now that a person can buy a complete 750W peak power 500wh battery 26" mtn bike with geared hub motor that is UL2849 certified and fully open standard for under $250 shipped on Amazon right now.
Cheap build opinion
Hello guys, I think about buying this kit and I have several questions. I'm lured with $100 price and I don't understand why nobody else in Warsaw is interested in this device. Am I going to be able to install PAS in this. It doesn't have counter, only 1-4V analog. What do you think about it...
endless-sphere.com
And see that is basically the problem with the whole world of geared hub motors.... almost all without exception were meant to be paired with cheap BSO type bikes like the ones commonly found in China rather than being optimized around a nice street bike. This is unfortunate because a street bike is the type of bike more likely to benefit from a hub motor than a mid drive and yet all the nicest street bikes (e.g. Trek Domane+ SLR and Cervelo Rouvida) ironically use low q factor mid drives.
It would be nice to see this forum have better understanding of what makes a good street bike and what does not.
Last edited:
No, way cheaper. People are trying to solve what they perceive would be a useful system for you (I’m guilty of that), but your actual requirements are very modest. Assuming you are a very fit rider already, it’s conceivable that you can output 200W during your climbs. 10%-20% assist would be 20w to 40W. This.means your battery requirement is very modest. Heck, maybe even a string of Duracell batteries would be enough. Anyway, battery costs will be very low. The motor can be tiny too. Your original idea of a friction drive may be the best one, since finding a non-RC motor that small may take a bit of searching.
What speed do you maintain with pedal only up the steeper hills?
Per the Grin simulator, you can climb 20% and never overheat with a Bafang G60 standard wind outputting 40W, with a 15 mile range using a 36v 10Ah bottle battery. A lot further if you’re not climbing 20% the whole time. Knowing your pedaling speed up those ascents will help pick the right motor.
Note: I would go with the upper power in your range. 20W really isn’t enough to appreciate. Probably more assistance from a big fart.
Last edited:
It should be mentioned that mid-drives eat up chains and cassettes/freewheels. Even with lube every 100 miles or so I change chain and freewheel just about every summer (1,000 miles). It will tell you when it's time (violent teeth skipping under heavy load).
metanewbie
100 mW
I go from 4/5/6 to 8 mph up fairly steep hills. 4 is when I carry my 20-pound dog in a doggy backpack and groceries in rear panniers. I basically would like the occasional assistance when I'm tired at the end of a long workday.
I've been considering this:
QR-E PRO +H70 Battery Kit – Ebike Conversion Kit-Qiroll
qirollshop.com
I know friction drives aren't without their issues. This one appeals because of the good tech support and I could easily enable/disable and swap it between the bicycles.
Mid-drive sounds nice but I want to ride my bicycle normal 80-90% of the time. The extra weight and maintenance might be overkill for my limited needs.
What do you think of the qiroll?
Similar threads
