eBike Kit for Dohan D7 fold up.

[beatlejuice]

With increasing age I am becoming more allergic to hills so I fitted an e-bike kit to my 'daily rider'. This has been a success now I want to fit one to my fold up. Does anyone know of such a kit? The main problem is the front wheel is only 75mm wide, like Brompton, however it has 20" wheels.

 

[dicko]

Look up Cytronex they are in Winchester I fitted their kit to my bike it works just fine I’m sure you will be ok. Click on their link and follow their measurements to see if your folder will be compatible.

 

[CXRAndy]

Is this your bike?

If the bottom bracket is standard threaded 68/73mm you could possibly fit a Tongscheng TSDZ2B motor and battery. Does your bike come with a rear pannier rack?
I fitted this TSDZ2 to my sisters Raleigh 7 speed folding bike.

I took it out and demonstrated it would pull me up an average 12% gradient hill whilst remaining in Z2 effort

 

[88robb]

With increasing age I am becoming more allergic to hills so I fitted an e-bike kit to my 'daily rider'. This has been a success now I want to fit one to my fold up. Does anyone know of such a kit? The main problem is the front wheel is only 75mm wide, like Brompton, however it has 20" wheels.

Sure. A front hub motor is a bad idea for your D7's small wheel. It will harm the steering.

Look for a lightweight rear hub motor kit made for 20-inch wheels. You will also need a small battery.

Companies like Swytch make kits for folding bikes, but search for "20 inch rear hub conversion kit" to compare options.

 

[CXRAndy]

Bafang do a rear motor hub with 103mm spindle width for 20" wheels

The rear 100mm wide dropouts can be easily sprung to go that wide.

Downside-rated at 250W , so will feel asthmatic assisting on climbs especially steep hills.

A crank based motor will better for it will develop more torque.

My sisters setup had 80nm torque and with all the extra peak power still only maxed out at 15mph pedalling rapidly at 100rpm.

A torquey motor is better than power for climbing as the legs get weaker

 

[beatlejuice]

Is this your bike?

View attachment 791153

If the bottom bracket is standard threaded 68/73mm you could possibly fit a Tongscheng TSDZ2B motor and battery. Does your bike come with a rear pannier rack?
I fitted this TSDZ2 to my sisters Raleigh 7 speed folding bike.
View attachment 791152

View attachment 791147
I took it out and demonstrated it would pull me up an average 12% gradient hill whilst remaining in Z2 effort

View attachment 791149

Thanks for your reply. I contacted Woosh Bikes about the feasibility for fitting one to my bike. They promptly replied and said yes they can fit a TSDZ3B to a Dohan D7 but they wouldn't recommend it and will not guarantee it. Something about there is no way of using the rear fixing-block with the D7 and this could cause the casing to crack.

 

[CXRAndy]

Thanks for your reply. I contacted Woosh Bikes about the feasibility for fitting one to my bike. They promptly replied and said yes they can fit a TSDZ3B to a Dohan D7 but they wouldn't recommend it and will not guarantee it. Something about there is no way of using the rear fixing-block with the D7 and this could cause the casing to crack.

If I understand correctly, they are talking about the bracket that holds the battery. Makes you wonder how these companies survive. Just a little fabrication with wood/metal or plastic.

I designed an underside plate to hold the battery bracket in place

3D printed in plastic.

I could have made a support out of wood, but Im learning 3D printing so take my opportunities

The whole premise with a generic kit is you make it fit.

 

[CXRAndy]

You could fit this battery bracket, which comes as a rear rack. Ive just ordered this battery

 

[CXRAndy]

This battery is likely too big for your folding bike 900Whr

I'd suggest a smaller one to fit your existing pannier rack

 

[beatlejuice]

Look up Cytronex they are in Winchester I fitted their kit to my bike it works just fine I’m sure you will be ok. Click on their link and follow their measurements to see if your folder will be compatible.

i looked at this option but believe it or not my D7 hasn't got holes for a bottle mount! The main frame tube connecting the front to the seat isn't round. This limits bodging options!

 

[beatlejuice]

Is this your bike?

View attachment 791153

If the bottom bracket is standard threaded 68/73mm you could possibly fit a Tongscheng TSDZ2B motor and battery. Does your bike come with a rear pannier rack?
I fitted this TSDZ2 to my sisters Raleigh 7 speed folding bike.
View attachment 791152

View attachment 791147
I took it out and demonstrated it would pull me up an average 12% gradient hill whilst remaining in Z2 effort

View attachment 791149

CXRAndy,​

What did you do to get the gearing correct for a 20" wheel?

beatlejuice​

 

[CXRAndy]

You can use websites like bike calc to punch in variety of gear ratios and wheel tyre sizes.

The speeds I quoted to you were from literally riding my sisters bike after I converted it to electric assist.

The gearing wasnt altered, it was what was on the chain ring of the motor 42t , and the original 7 speed cassette on the Raleigh folding bike.

This gave plenty of low gears for climbing steep hills and top speed pedalling in the flat at 15mph. I found the stability and overall folding bike geometry a bit sketchy when freewheeling downhill above 25 mph. So there is no need to have a folding bike capable of going that fast on the flats.

Does your folding bike have a rear rack already fitted?

I sent you a private message. If you like to continue the conversation I could assist

 

[beatlejuice]

You can use websites like bike calc to punch in variety of gear ratios and wheel tyre sizes.

The speeds I quoted to you were from literally riding my sisters bike after I converted it to electric assist.

The gearing wasnt altered, it was what was on the chain ring of the motor 42t , and the original 7 speed cassette on the Raleigh folding bike.

This gave plenty of low gears for climbing steep hills and top speed pedalling in the flat at 15mph. I found the stability and overall folding bike geometry a bit sketchy when freewheeling downhill above 25 mph. So there is no need to have a folding bike capable of going that fast on the flats.

Does your folding bike have a rear rack already fitted?

I sent you a private message. If you like to continue the conversation I could assist

CXRAndy,​

Thanks for your reply. It has a rack similar to the one shown in your photo. Hills are a prominent feature of where I live, so low gears are welcomed. Going fast on a fold up bike with small wheels on poorly surfaced roads is a little too interesting for my advanced age!

beatlejuice​

 

[CXRAndy]

Do you know what the largest cog on the rear cassette is?

For reference my sisters bike has a Cassette
14-28t 7 speed. Runs a 42t chain ring on the motor

If its like my sister Raleigh, I dont think you will have much of a problem cycling up hills with a TSDZ2 motor.

If you read my private message I sent you. I can help if you want

 

[beatlejuice]

Do you know what the largest cog on the rear cassette is?

For reference my sisters bike has a Cassette
14-28t 7 speed. Runs a 42t chain ring on the motor

If its like my sister Raleigh, I dont think you will have much of a problem cycling up hills with a TSDZ2 motor.

If you read my private message I sent you. I can help if you want

Don't seem to have your message.

beatlejuice