Conversion kit build for Brompton

[omarshaffi]

Hi All,

Fairly new to ebikes...I’ve been tinkering with Californian Go Peds for the last 15 years but as much as I love them clearly petrol engines are always met with frowns and crossed police officers!

I have my Brompton and want to go down the route of building my own kit not use Nano or Swytch etc.

I’ve tried to read up as much as I can on this site with respect to Brompton builds and have seen some threads about the Q70 motor. Is this still an ideal motor to opt for? Looking at BMS site I can see a Q75 and Q85 as well. Are these newer models?

They have an option to purchase a built wheel with a Q85 motor would the 16” fit onto Brompton forks or would they need to be widened as not sure how to check without physically having it.

Any and all help welcome.

Thank you everyone

 

[Woosh]

only the Q70 is specifically made to fit the Brompton fork.

The Woosh kit for the Brompton is based on this motor and available now.

https://wooshbikes.co.uk/?hubkits#q70kit

 

[omarshaffi]

Ah thanks that’s useful. I like their kit it looks neater than having a bag and close to Dereks build where he used a Bosch battery.

So with the Q70 the forks don’t need widening? Can anyone recommend which pedal sensor to use as BMS haven’t replied despite messaging twice

 

[Nealh]

Any pedal sensor will work if fitted correctly.

 

[omarshaffi]

Thank you. When referring to poles on a pedal sensor is that to do with magnets and the more poles there are the greater the sensitivity

 

[Nealh]

QUOTE="omarshaffi, post: 564949, member: 30536"] Thank you. When referring to poles on a pedal sensor is that to do with magnets and the more poles there are the greater the sensitivity [/QUOTE]

Generally yes but tbh whether 8 ,10 or 12 you won't feel much between them.

 

[vfr400]

I’ve tried to read up as much as I can on this site with respect to Brompton builds and have seen some threads about the Q70 motor. Is this still an ideal motor to opt for? Looking at BMS site I can see a Q75 and Q85 as well. Are these newer models?

They have an option to purchase a built wheel with a Q85 motor would the 16” fit onto Brompton forks or would they need to be widened as not sure how to check without physically having it.

The 16"rim that they offer is much smaller than a Bromton one so is not suitable. If you want to buy from them, you have to buy the bare motor and build it into your own rim. This one:

Sun CR18 16 x 1 3/8 / 349 Side Wall Rim 36 Hole

Presta Drilling Eyelet. A very high quality rim in the 349 size, with ABT (advance brake track) machined sidewall, with eyelets, drill valve to schraeder if needed. Overall width 22.4mm, inner well width 17mm. Weight: 300g ERD - 340mm

www.sjscycles.co.uk

Woosh kit would be a lot simpler.

 

[vfr400]

Thank you. When referring to poles on a pedal sensor is that to do with magnets and the more poles there are the greater the sensitivity

I'd say no - not that you'd notice. It would be theoretically possible to get a faster response with more magnets, but I don't believe that the software is programmed to take advantage. Some controllers have a fast response and some a slow response regardless of the type of pedal sensor. With a KT controller, I'd challenge anyone to tell the difference between sensors with different numbers of magnets.

 

[Woosh]

I like their kit it looks neater than having a bag and close to Dereks build where he used a Bosch battery.

thanks for the link.
I should have done more home work before trying to reinvent the wheel!

I did make an adapter for my kit to use the Bosch 36V battery too.
But I knocked that up over a weekend and it shows:

 

[omarshaffi]

thanks for the link.
I should have done more home work before trying to reinvent the wheel!

I did make an adapter for my kit to use the Bosch 36V battery too.
But I knocked that up over a weekend and it shows:

No what you made is brilliant. I assume you designed it and made a prototype first and then had it produced...this is what product design is all about and not something a lot of people can do

 

[Woosh]

I am thinking that in most situations, the weight of the battery over the front wheel is not a problem because it's low down, not perched on the handlebars and not interfering with the ride quality.
What I don't want is having to remove the battery and carry it with me inside the shop. So the priority is a kit that has a lock to the frame.
Even the bosch battery was locked to the frame.
Don't know about the wisdom of leaving £1500 lashed to the lamp post outside the shop though.
I did have the battery mounted to the seat post for a while but I don't like lifting a weight every time I need to adjust the saddle post.

 

[omarshaffi]

The 16"rim that they offer is much smaller than a Bromton one so is not suitable. If you want to buy from them, you have to buy the bare motor and build it into your own rim. This one:

Sun CR18 16 x 1 3/8 / 349 Side Wall Rim 36 Hole

Presta Drilling Eyelet. A very high quality rim in the 349 size, with ABT (advance brake track) machined sidewall, with eyelets, drill valve to schraeder if needed. Overall width 22.4mm, inner well width 17mm. Weight: 300g ERD - 340mm

www.sjscycles.co.uk

Woosh kit would be a lot simpler.

Thank you for this link to the room. With the Q 70 motor in place which spokes should be used to lace up this motor

 

[vfr400]

Thank you for this link to the room. With the Q 70 motor in place which spokes should be used to lace up this motor

Use a spoke length calculator to get the length based on the motor dimensions and rim EDR. I used normal 14g spokes, which I cut down from longer ones I had hanging around, and I threaded them with a threading tool I bought from EBay. The length is shorter than what most spoke suppliers can handle, so you'll need to find someone that does custom length spokes.

 

[omarshaffi]

Use a spoke length calculator to get the length based on the motor dimensions and rim EDR. I used normal 14g spokes, which I cut down from longer ones I had hanging around, and I threaded them with a threading tool I bought from EBay. The length is shorter than what most spoke suppliers can handle, so you'll need to find someone that does custom length spokes.

Thank you I will try and find a spoke rim calculator

 

[Nealh]

For custom spokes use Ryan Downes at spokesfromryan .com.
Excellent service and delivery time.

 

[vfr400]

Thank you I will try and find a spoke rim calculator

Edd, an easy to use spoke calculator

An easy to use spoke length calculator with a large amount of hubs and rims in its database.

leonard.io

When they say flange dia, they mean the pitch circle diameter of the spoke holes, which you get from the motor drawing or by measuring it on the motor. Rim ERD should be shown in the rim listing. I used a one-cross pattern.

 

[omarshaffi]

Edd, an easy to use spoke calculator

An easy to use spoke length calculator with a large amount of hubs and rims in its database.

leonard.io

When they say flange dia, they mean the pitch circle diameter of the spoke holes, which you get from the motor drawing or by measuring it on the motor. Rim ERD should be shown in the rim listing. I used a one-cross pattern.

Thanks did you fit your assembly onto a brompton?

 

[omarshaffi]

Hi

Would anyone know if this PAS would fit the brompton. Its the only one that splits apart so avoids removing the crank.

Dual Hall Sensor D12 Signals Easy Installation PAS Assemble Left

Dual Hall Sensor D12 Signals Easy Installation PAS

bmsbattery.com

 

[Woosh]

yes, it fits the Brompton OK but why do you want to lace a wheel and worry about removing a crank?

 

[omarshaffi]

yes, it fits the Brompton OK but why do you want to lace a wheel and worry about removing a crank?

If there are parts I can buy that avoid removing components then I would select them. I know I can buy your woosh kit but dont have the budget and want to learn myself as well. It seems lacing the Q70 is the only option as nobody sells it already laced up.