This is a 'Let's all save cwah from himself' thread :)

[oigoi]

Ultimately I have more admiration for a machine that someone has created themselves, I appreciate the thought and ingenuity that is required, whereas to buy an off the peg machine all you need is money.

The downside is you can waste some money along the way, buying parts that turn out to be the wrong ones, but with perseverance you can end up with something better that is designed to your own requirements.

In a way you end up doing your own research & development, something which a ebike manufacturer has already done on the models they produce.

 

[Scottyf]

so if it's too fast, I can still set the speed lower. I'm doing that with my actual bike now.

Whats the current speed you travel at?
I think on my ebike I have the 44 or 48 front with a 14-?? not sure what the top is and I can just about be comfortable at 25mph ish.

Unassisted I actually use the same front but a higher geared rear of 11 teeth.
So if i put enough effort in down a hill I actually go quicker than my electric side takes me.

The beauty of the BPM @ 20amp ish is that if you pedal moderatly your speed pretty much stays the same even up hills.

Even so I still think a decent option of a folding bike and jsut over volting a smaller motor would be a compromise. You can still get those 20mph+ speeds and not have to worry about better brakes or upsetting the handlnig with Lipo.

My motor @ 44.4v nominal would do 308rpm in a 28inch wheel (25mph) If I pushed to 15s lipo it would probably hit the high 30mph depending on wind resistance.
However even at 25mph it chews up 21 wh/m.

at 30mph I would allow for 30wh/m.

 

[jerrysimon]

JerySimon, the neutral gear is a gear you can "unplug" once folded. So when you move the bike backward the pedal doesn't move at all. Quite interesting concept. Why couldn't I move this bike into shop but it would be possible with the Dahon hybrid? What's the main difference?

Thanks for explaining the neutral gear. That is really quite clever.

Re taking bikes into shops etc the point I am trying to convey is that wheeling any bike into a shop with wet dirty wheels will likely get frowned on. You may get away with it but it is much better if you can carry it. The Dahon could be carried because it is light that is why I said it would be easier to carry than the one you are looking at that has to be wheeled in.

Again the Brompton scores over other options in that even when folded none of the wheels touch the ground when you put it down. It has two small skate board type wheels and a jockey wheel on the rear mudguard that both hold it off the ground and allow it to be wheeled.

Anyway I have said enough about the Brompton and what I consider to be the advantages.

You are fortunate in that you can now sit back and watch Dave (d8veh) convert his Dahon Jetstream and Alan (catsnapper) convert his Dahon hybrid and then decide which way you want to go. Either following their lead or look at other options.

This forum is such a great resource for its many subscribers

Regards

Jerry

 

[flecc]

Re taking bikes into shops etc the point I am trying to convey is that wheeling any bike into a shop with wet dirty wheels will likely get frowned on. You may get away with it but it is much better if you can carry it.

Next time he gathers up trolleys from the car park in the wet and takes their hundreds of wheels in, I'll have to tell the lad at my supermarket he's being naughty!

 

[jerrysimon]

There is a contradiction there for sure and the same thing could be said about wheelchairs, push chairs etc. I however would be very surprised if someone did not say anything if you wheeled the bike shown in this thread, up and down the isles in a supermarket or through a shop with wet dripping dirty wheels without someone saying something.

Then again I have never done it, but have seen many posts in folding bike forums discuss it.

Regards

Jerry

 

[flecc]

I'm sure you're right Jerry, trolleys belong, bikes don't. It's all about perception.

 

[cwah]

Scottyf, for now with my Conhismotor bike, I can set the speed between 34 kph max, 25 kph max and 15 kph max here:

I suppose I should be able to do the same thing with the new motor and be able to choose between 25 kph, 35 kph and 50 kph max speed. And maybe most of the time I'd be around 35 kph or 20 mph.
Wouldn't that be possible?

JerrySimon, the Brompton is definitely an amazing bike. If only I can get a motor that can go faster and that would fit... that would be perfect. 209 was the good candidate but at 27wh/miles at 22 mph, it definitely doesn't worth it.

 

[Scottyf]

What conhis motor?
Is that a direct drive from what I read on other forums and the net?

Could you not use that motor but over volt it to bring the speed up to the desired range.

 

[cwah]

Scottyf, this is this bike:
http://item.mobileweb.ebay.co.uk/viewitem?itemId=230662193393

Basically, the bike in itself is too heavy (24kg). I can modify the bike and increase the bike speed but I prefer to invest on a bike of better quality/lighter.

 

[Scottyf]

Is the issue just about the weight or its portability or both?

Can you live without suspension?


I still think a smaller motor, Higher speed with less amp's and weight as well as a more rigid folder with lipo is the only possibly way to do it in an off the shelf design that you can bolt together. Anything else and you may have to go down the fabrication road.

Its really picking a bike thats light enough to accomidate you. But anything with electric is already creating a heavy bike.

I always forget how light my bike is unassisted with V brakes, single walled wheels and some lighter tires. An my bike isn't even light on the grand scheme of things. But its easy to carry so long as space isn't an issue. Even it it is taking the wheels offs takes about 2 mins.

But what a BPM motor on already there's an extra 4KG. I have to run better brakes so disks which weigh more. I then swap to double walled wheels. There's some more weight. Then Marathon Plus tires. Some more weight.

It all adds up, then the battieries I lug about and a 9 fet controller in a back pack away from the bike and on me to carry the bike is still harder to lift and its not even that heavy at 17kg. But the balance of the weight is thrown about.
The Batteries (44v 15ah) and controller themselves plus a small tool kit = 5kg (I can cut it down to about 1.5kg with a 44v 5ah battery)

This makes its portability more difficult. I can no longer remove the rear wheel without taking 10 mins and a set of tools.

Place all that on the bike and the handling changes. Not uncomfortable but you know the weight is there.


If your bike alreay weighs 24kg its not exactly a heavy weight in the electric arena. Moving the batteries can make a large difference. But getting anything less than 18kg in my mind is already a light electric bike.

 

[cwah]

Issue is with the weight and the portability. It's a really really big bike even when it's folded.

Here is a picture of the bike when I was carrying it to France:

As you can see... it's huuuuge. People were asking me if I was carrying my home lol.


I can absolutely live without suspension, but I was thinking about getting a full suspension bike like the dahon Jetstream at around 12 kg. So it's almost as light as a normal bike.

Unless I stick to the Dahon uno but it doesn't have any brake.

I'm still thinking about the Brompton but it seems that it's highly un-efficient with the 209 (the only able to reach the speed I'm looking at). Something like 26wh/miles at 22 mph. With that kind of efficiency I'd end up with really heavy batteries.

It seems that the smaller the wheel, the less efficient the motor is...

 

[Deleted member 4366]

I think I'm agreeing with Scotty. You should get your present bike to perform how you want it, then see how much it weighs. By getting a lighter folding bike, you'll end up saving about 3kg from the total, which isn't a lot. however, a 20" wheeled bike is a lot easier to fold, carry and store. So, use your current bike as a test-bed and then move all your components to the new bike. You may only need a new rim, or worst case a new motor and wheel, and you'd easily be able to sell anything that you can't use.

 

[catsnapper]

Unless I stick to the Dahon uno but it doesn't have any brake.

I'm still thinking about the Brompton but it seems that it's highly un-efficient with the 209 (the only able to reach the speed I'm looking at). Something like 26wh/miles at 22 mph. With that kind of efficiency I'd end up with really heavy batteries.

It seems that the smaller the wheel, the less efficient the motor is...

The Uno has a front brake, a legal requirement in the UK, the rear is a hub or cruiser brake, so a front motor is needed - limited to a Cute or Tongxin.

The Xootr Swift has 132.5mm rear and standard 100mm front dropouts, giving a good potential choice of motor.

You can use this simulator ebikes.ca Hub Motor and Ebike Simulator with
either the 9-Continents front or rear motor or the Ezee motor for 20" wheels The Grin Cyclery.

I use the Ezee 26" motor with a tandem and a 36V 15Ah Ping battery. It can exceed 20mph and has a good range.
With a small but efficient LiPo pack and the Ezee motor on a Swift folder you would not be slow

Small wheel setups are not less efficient, you need the right motor for the the wheel size and intended use, BUT some compromise is ALWAYS needed if you want to have just one bike

Alan

 

[cwah]

It's indeed not much weight lost, but it's also because I want a faster bike. So at the end I'll have a faster and lighter bike. Not that much, but enough to justify the change.

I'm planning to sell the complete bike to make things easier. If I move part from my actual bike to the other I'd have a lot of work to do. For example, changing the motor from 26" to 20" is going to be a though task. Selling it back would probably be much simpler.

Catsnapper, I just check the Xootr Swift, it's at 11.5 kg. At 12.5 kg I can have a double suspension bike (Dahon jetstream). Wouldn't that be better to have the jetstream? However, there is a second hand Xootr on ebay I don't know what that worth:
XOOTR SWIFT FOLDING BIKE | eBay

Ezee kits are something like 5 times more expensive than a Bafang kit. Do they worth their price?

And also, you are the wheel building specialist? Are you the one we should call when we need to lace a wheel? If it's yes, I may just buy the motor from BMSBattery lol.

ps: If small wheel are not less efficient, why is the consumtion so high on the crystalyte 206? On this blog, the guy uses 16.86wh/km at 35 kph max speed.
Bike Friday eTikit Review Part 1 « The Lazy Rando Blog…

 

[catsnapper]

The Swift lets you choose a front or rear motor as it has a 100mm front dropout, plus it is much less 'bendy' frame than a Dahon. The downside is it doesn't fold as small as a Dahon or Brompton. If you're settled on a rear wheel motor, then the Dahon may suit your needs better.

I wasn't talking about the Ezee kit, just the motor. At 275 USD against the BPM at 139 USD it's dearer, but not (in my opinion!) out of proportion to it's higher quality, ease of servicing and higher power. Only available as a front motor, you need the kit to have a rear version.

Yes, I'm the wheelbuilding specialist, if you buy just the hub, I'll be happy to lace it into a strong, high quality wheel for you It's often the cheapest and best answer.

Re small wheels: You are making a statement based on the figures in one review, not on any scientific or comparative basis. If you use the simulator to compare the Ezee 20" and 26" motors on a level road and full throttle you will find the figures very similar, on a 10% slope the smaller wheel is slightly more efficient. My real world Cycle Analyst figures confirm these figures are a good guide to reality.

Alan

 

[cwah]

That's great. I can call you then if I buy from BMSBattery? If you can lace the wheel I won't have to purchase the kit from them. Just get the motor and send it to you. where are you located?

I strongly prefer the rear motor because it's stealthier.

Do you have know if I can fit a rear (strong) motor on Brompton rear wheel? I went to Evans cycles today and even the Brompton appeared big to me. So I probably need a Brompton... But no way I travel at 20 mph. I need something faster. Any idea how?

 

[cwah]

Actually, the Dahon Uno is not that big compared to the brompton:

 

[jerrysimon]

Do you have know if I can fit a rear (strong) motor on Brompton rear wheel?

I doubt it. The back frame swings under the the frame when folding. The added weight of a rear motor would likely interfere and compromise the fold, added to the fact that the rear gearing arrangment is bespoke in terms of the chain tensioner.

Regards

Jerry

 

[cwah]

Jerry, if you wanted your brompton to be fast. Something like 30 mph. What would you do?

 

[catsnapper]

If you want to go anywhere near as fast as you say with a rear motor, please don't get a Brompton - it's not designed to be powered like that, and the 16" wheels add to the problem of handling and stability.

The Uno isn't suitable either, it can't take a rear motor as it's too narrow at 120mm dropout, and the front only takes a narrow, small motor, like all standard Dahon forks on 20" folders.

That leaves, a Swift(strongest) or a Dahon (smaller fold) other than the Uno. These are NOT recommendations, just eliminating the impractical, the choice is yours to make.
There are plenty of videos of people lying on their back in the road with a startled look on their face after a generous twist of the throttle while sitting back on a 20" wheeled e-bike - wheelies are one thing, looking at a bike with a spinning wheel falling onto you is another

I'm happy to build the wheel(s) for you, but until you decide which path you're following, I'm signing off from this thread for now. Good luck in eventually making your choice!

Alan