If you have 36v, you can solve that by going up to 48v, which will give you 33% more torque. If you have steep hills, want a hub-motor and aren't a club cyclist, 48v is mandatory. I find it really surprising that manufacturers have more or less standardised on 36v, when 48v costs the same, is more efficient and gives more power options.

Yes I can see that more volts is less amps for the same power. Less likelihood of losses cause by cabling and joints. Definitely a consideration. So many helpful posts, I'm glad I came here and I'm glad I asked.

However, I have had experience with 4 different hub motors so far but no experience of any cd motors.

A hub motor works effectively as a CD motor stuck on one of the middle gears.

The woosh website gives useful charts that (in my view) gives a good indication of what performance to expect where the rider is not able to contribute much power.

http://wooshbikes.co.uk/?motorcharts

Thanks, useful link I hadn't seen before. For much more varied charts see https://www.ebikes.ca/tools/simulator.html

Thanks, useful link I hadn't seen before. For much more varied charts see https://www.ebikes.ca/tools/simulator.html

The motor simulator is very good. For the purposes of comparison, I have compared a 95 kg 'not as fit' cyclist (50w legs)with a 75 kg fit cyclist (200w legs), both with bikes weighing 25kg and facing a 8% hill. The lighter fit cyclist will ascend at 20.4 kph (12.8 mph) and the not so fit heavier cyclist at 9.7kph (6.1 mph).

Notice also that the motor on the slower bike will consume 21.2 amps (although controller is 14 amps battery current max). This is due to 'flywheel/flyback current' and will heat up the motor and controller. So its really important to take the weight and fitness of the cyclist into account.

 

https://www.ebikes.ca/tools/simulator.html?motor=MXUS_XF07&batt=B3614_PF&cont=cust_14_25_0.03_A&wheel=700c&mass=120&grade=8&motor_b=MXUS_XF07&batt_b=B3614_PF&wheel_b=700c&mass_b=100&grade_b=8&cont_b=cust_14_25_0.03_A&hp=50&hp_b=200&k=1&k_b=1&throt_b=100&add=false&blue=Lbs&kv_b=6.366&bopen=true

 

Edited October 9, 20196 yr by Sturmey

PeterPi, do youself a favour and arrange a test ride (or two) with Halfords in Llansamlet.

The motor simulator is very good. For the purposes of comparison, I have compared a 95 kg 'not as fit' cyclist (50w legs)with a 75 kg fit cyclist (200w legs), both with bikes weighing 25kg and facing a 8% hill. The lighter fit cyclist will ascend at 20.4 kph (12.8 mph) and the not so fit heavier cyclist at 9.7kph (6.1 mph).

Notice also that the motor on the slower bike will consume 21.2 amps (although controller is 14 amps battery current max). This is due to 'flywheel/flyback current' and will heat up the motor and controller. So its really important to take the weight and fitness of the cyclist into account.

 

https://www.ebikes.ca/tools/simulator.html?motor=MXUS_XF07&batt=B3614_PF&cont=cust_14_25_0.03_A&wheel=700c&mass=120&grade=8&motor_b=MXUS_XF07&batt_b=B3614_PF&wheel_b=700c&mass_b=100&grade_b=8&cont_b=cust_14_25_0.03_A&hp=50&hp_b=200&k=1&k_b=1&throt_b=100&add=false&blue=Lbs&kv_b=6.366&bopen=true

 

[ATTACH type=full" alt="motor.jpg]32377[/ATTACH]

 

If you had chosen a 26" wheel the fit guy would climb at the cut off - personal experience on a 9.4% average climb - 20 km/h on the gnarly bits up to 13%. And contrary to those who ride a hub motor badly it helps a lot to be in the correct gear.

 

I have a couple of spots on my commute which flirt with 16-17% and can't top 16 km/h there in the correct gear with my mid-motor. If I drop down a gear of course I go slower - 14 km/h ish - but both battery and motor thank me for thinking about their health.

PeterPi, do youself a favour and arrange a test ride (or two) with Halfords in Llansamlet.

Aye, I suppose a ride down to the Liberty and back might be a decent test.

Any of their bikes give you a feel for what a conversion is going to be like?

Any of their bikes give you a feel for what a conversion is going to be like?

Don't know what they've got in the way of demos, tell them you can't decide between crank or hub drive, maybe they'll let you try both. I've never ridden a crank drive so I can't comment, all bikes ride diffently but there is not a huge difference between rear drive 250watt motors so it will give you a pretty good impression of what to expect.

I have a couple of photos here. Does this look like its compatible with most/any mid drive kit?

 

Thanks

Pete

Looks good plenty of chain wheel clearance to rear stay.

The only thing you may find is the inside of the BB shell may need cleaning up (weld nibs removing or over any weld ) with a file or Dremel type tool.