gmcjetpilot

HELP! Brompton Folding Bike 16" Wheels Conversion
A start up Swytch electric bike kit is coming out with an new kit and have a signup to be notified. I think it will be more than I want to pay. google swytch-ebike-conversion-kit-for-brompton. Their set up is super clean. If they are in the $500-$600 range that is the way to go. However I think it will be $1000.

QUESTION - does anyone know of a good (and cheap relatively speaking) kit or source for parts for a roll your own eBike conversion. I am a capable DIY'er and can buy ala carte and wire things. I have found some kits on eBay and AliExpress for 16" front wheels. I am looking at about $380 (with shipping) and $130 for 36v/10aH battery with BMS. Total about $500.

CRITERIA: - Since it is a folding bike and want to still fold the bike, I will put the battery, controller and display unit all in one bag on the handle bar or head tube. Brompton's and clones have a bracket on head tube, made to mount a bag. I will have to disconnect the hub motor, throttle and PAS pedal assist system sensor. Which leads me to my last question. Do I need a PAS?

QUESTION do you need the pedal-assist system (PAS) sensor on crank. The kits come with it, but can I leave it off? Can't I just use the throttle as needed when pedaling,. Not sure I can fit it on based on type of crank I have? The less wires and connection to disconnect to remove from bike to fold the better.

The last option is do nothing and actually pedal the bike 100% under my power, as bike spirits intended.

2_i 

There was a lot of discussion of practical experiences with Brompton electric conversions on the German-language Brompton forum. Unfortunately, the archives are not accessible right now. Maybe berlinonaut can comment.

Winfried

https://www.swytchbike.com/p/swytch-...-for-brompton/

gmcjetpilot

If you read my post I mentioned swytchbike... I contacted them many times before I got a response. Some vague info was given. They are pretty shy on hard data, but I am on their mailing list to be notified when their kit is available. I believe their price will be near $1000. I can get a China 16" wheel with e-motor kit for $310 (wheel, motor, controller, display, throttle, pedal sensor). The battery is extra, $140. So $450. Add $50 for tire and tube, so I don't have to take if off my original rim.

I am not going near $1000. I am sure the Swytch is better but $1000. They say 50% off their initial sales of kits for those on list. I am on list. If I can get switch for $500 great. So I am going to wait.

I have laid out where I will put battery and controller so I can fold the bike without removal. Also I will need to buy new tire and tube. I want to set this up so I can undo it easily without any permeant alteration. I am pretty sure it can be done for under $500 with good results. However Swytch looks good, so I will hold off for a bit. I have enough info. For now I will have to pedal manually. I can use to lose a few LB's.

tds101 

The only way they sell the ebike kit for 50% off is if you pay for it, then wait (I believe) 6 months or so for it to be shipped. linberl has this setup if I'm not mistaken. She said it's quite good.

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Any system that has a throttle can do without the pedal assist sensor, as long as that's what you want. There's kits out there that have throttle only. Hilltopper is an example,... Unfortunately they don't have a Brompton/16" sized wheel.

berlinonaut

From my experience the Swytch is a pretty low end kit. At it's regular price it is potentially overpriced massively but then in the end almost no one pays their regular price. Still: If you look on the price as your main criterium you will probably end up with a very bad solution that leaves a lot to be desired.

The motor used on the Brompton front whees today is typically an Aikema as it offers 74mm width in opposite to others. Brompton themselves do use a motor they constructed on their own and before the 74mm Aikema existed it was necessary to spread the forks of the Brompton a bit to fit a motor.
So the motor is basically set (though AFAIK there do exist a 200W and a 250W version of the motor - but if you are greedy you will have to use the cheaper version). Other than that you need a couple of bits (nothing is spectacularly complicated or expensive) and obviously the battery. Cheap batteries are often trash and not worth the money and sometimes even dangerous.
The intelligence of a kit is in the combination of components and how it is programmed. If you buy cheaply, you'll end up with a non decent solution.
Technically you do not need a PAS but then you need a controller that can live without one. Effectively you then have an electric moped, not a bike. May be interesting to some, but in my eyes this has not much in common with actually riding a bicycle. Better eBikes (as the Brompton Electric) do use a Torque sensor instead of a primitive PAS and this is again a totally different (and way better) world.
Regarding your plan to disconnect everything from the motor when folding the bike: This is an advantage that the swytch offers and in a more clever way the Nano kit (and obviously the Brompton Electric). The connector on the motor cable is not suited to constantly connecting and disconneting. Once more the Brompton is due to the foldability more complex than normal bikes. So buying from someone who has experience with creating a good working kit, programming it, uses good quality components and offers working and practical solutions to the special needs of the Brompton is definitively worth money. I do own a Swytch Brompton kit (first generation) and was not impressed with it in many aspects. So in the end often you get what you pay for and as you did not state what problem you want to solve (so what to use the bike for) it is impossible to give sensible advice apart from: Definitively don't selecte by the price alone.

If it is a good idea at all to electrify a Brompton clone is a different question. The forks may be able to take the forces of the motor or not - in the worst case you may find it out painfully.
As you didn't state which country you are living in it is an open question wether not using a PAS is legal in your country or not - in many countries it is not legal to use a gas grip only.

kwantani

have you considered RubbeeX conversion kit?

invisiblehand

That's not much battery. My recommendation is buy enough battery for relatively extreme cases since that's when you'll really want the e-assist.

PAS is nice if you want to default to a tiny bit of power to offset whatever additional resistance the motor causes. You certainly don't need it.

gmcjetpilot

Thanks for bumping the thread.

If I did not mention I have two folding bikes. 3Sixty (Brompton Clone) and Greenzone (like a Zizzo or Tern). I don't "need" electric but want it.

• Passed on buying a used RubbeeX as shown above for sale on eBay awhile back. I kind of regret not buying it
• Looked at a roll your own system from China, 16" powered hub rim, controller, It was not free and you had to integrate it and buy battery.
• The Swytch -. I got on their to buy list for the 2.0 version at introductory price to be disclosed. It was released awhile ago. Saw the price with discount and nope.
• There is another system that bolts down low where the kickstand goes (would work on my Greenzone folding bike not Brompton clone) w/ friction wheel on tire.

For now No Pedal - No Go (unless using gravity down hill). I also got side tracked with my 1983 Bianchi Randonneur Touring Bike I bought new in 1983. I spent 6 months restoring it, including sourcing a replacement fork, having custom modifications done to a new fork I sourced to match the original front fork configuration (original one went bye bye due to recall by Bianchi, long story). It came out great. Just finishing it. It rides like dream. No E-Bike add on wanted or needed on this beauty

Right now the roll my own with Chinesium parts might be the way to go if price is right. May be a Swytch system used comes up for right price. I just have to justify the cost and desire. Still looking but not going to pay a fortune or more than the cost of the bike to make it an E-Bike. Shipping from China is higher especially for a rim. Someone suggested just buying the hub and lacing up my own rim. I don't want to permanently convert the bike. I want to retain the ability to go back easily.

Keep those post coming with ideas.