20" front wheel hub motor?

[rikigai]

Dear all

I am looking for recommendations for a kit for a 20" front wheel. I have two bikes with 20" wheels (one a trike, one a minivelo) that I am considering converting. I ride in London so, largely flat-ish but with some hills and bridge inclines etc. It's not for riding very long distances: 5-10 miles in any direction, though it would be great if the battery could sustain 20 miles with gentle pedalling. I will remove the battery when locking it up, for charging and security. Not averse to wearing the battery in a backpack. From what I have gleaned, a 36 volt, 10amp set up with a 250w motor would be about right (do correct me if you don't agree). Not looking to spend a fortune but I don't want some dodgy nonsense and I haven't got much in the way of technical and mechanical ability. Perfectly happy to pay someone £100-abouts to install it. £1,000 all in? Less if I can get get away with it. Not a fair-weather cyclist so must be waterproof. Roads in London are dreadful so must be able to take a shake and a bash. Have thought long and hard about hub or mid-drive and I may wait to see how the new sunstar motor shapes up but in the meantime I am looking at hub conversion options.

Lest it be said, must be road legal. I can't be arsed arguing with the Met.

What thoughts?

Thanks for your help!!

 

[eHomer]

Snap...

Two of my bikes share the same motorised 20" front wheel, a Hase recumbent trike and a Dahon Boardwalk folder.

It was such a successful installation on both that I'll probably buy another wheel, so that I can leave them both setup ready to ride.

I used a BMS supplied Q100 328rpm 250-350w hub motor, already laced into a 20" rim. Both the bike and the trike are permanently fitted with BMS S06S sine wave controllers and LCD panels, pas sensors and break cutoffs. So switching the motor is just a matter of unplugging it at the hub via the waterproof connector and swapping the wheel over.

The same battery is used in both, an aluminium cased 36v 10ah lithium ion, that I bought three years ago as part of another cheapo kit.

Either of them give a top speed of around 18mph with a range of about 25 miles, with moderate assistance. I live in a pretty flat area, but I'm a heavy bloke, at 95 kg, so maybe that cancels that out a bit.

I would say at current prices, that "kit" of parts from BMS for one bike would be about £200 plus the battery.

Your last stipulation "must be road legal", would be tricky to accomplish with a DIY build anyway, as far as I understand. The infamous sticker/plate being missing, for a single build.

As far as the intention of road legal goes though, it would be very close, as it would comply with the spirit of the current UK regulations (plus 3mph), and the Q100 motor is such a tiny looking motor, almost resembling a dynohub.

 

[Geebee]

Ezee sell a legal kit built into a 20" wheel and with a 2 year warranty.

 

[rikigai]

Thank you for your suggestions.

If I were to buy a motor such as those recommended above, can anyone recommend someone/a shop in London that will complete the wheel build for me?

 

[eHomer]

BMS do sell the complete wheel and motor ready built for £60, but unfortunately the shipping adds another £95, and then probably another £35 or so if you get hit by customs as well.

The motor on it's own is £50 plus the much lower £40 shipping, meaning the dreaded customs and vat should only be around £25.

So it's a £75 overall difference.

 

[rikigai]

For my trike I'd like to use the wheel I have. Sorry, should have explained.

 

[eHomer]

No problem, quite understandable.

 

[Cyclezee]

Ezee sell a legal kit built into a 20" wheel and with a 2 year warranty.

Good shout Geebee,

Of the kits that we supply and install the eZee would be the best choice especially if the battery needs to be carried in a back pack with a quick release connector to the controller.
Although we have complete 20" motor wheels including Schwalbe Marathon Plus tyre, we can custom build a motor into any double wall rim provided it uses 36 spokes.

 

[rikigai]

Good shout Geebee,

Of the kits that we supply and install the eZee would be the best choice especially if the battery needs to be carried in a back pack with a quick release connector to the controller.
Although we have complete 20" motor wheels including Schwalbe Marathon Plus tyre, we can custom build a motor into any double wall rim provided it uses 36 spokes.

Thanks.

How much extra would the wheel build cost?

Is the quick release connector extra?

The ansmann you sell is rated at 27nm torque. Is there a higher torque version for the ezee motors suitable for a 20" wheel?

The ezee motor is pretty chunky. On a 20" I am guessing this makes disk brakes (not hydraulic ones) impossible. Is the ansmann small enough for a 20" wheel with disk brakes?

 

[Cyclezee]

Hi Rikigai,

We charge £25 for a wheel build into your existing rim, but as I said earlier eZee kits come with a complete motor wheel already built and fitted with a tyre so there is no need to use your existing wheel.

A quick release connector cable would be £5 extra.

The eZee and Ansmann motors are the same width although the eZee motor is larger diameter.

Both motors disc brake compatible and can be supplied with whatever diameter disc rotor you require.

Please do not be mislead by torque figures that you see quoted by some manufacturers, in some cases they are a work of fiction.

It is extremely important to note the speed rpm and efficiency at a given torque level.

For the eZee 250 rpm motor, the typical value is :
30 N-m at 185 rpm , with 75 % efficiency
24 N-m at 250 rpm , with 80 % efficiency

As others will testify, the eZee is a very torquey motor.

We also offer another option the Heinzmann DirectPower DD system,
Below is an example fitted to a Hase recumbent tandem.



I hope this helpfull.