New member - with questions !

[Mendip99]

Good morning

I have been looking at the forum for a while and now taken the plunge, after a lifetime of cycling powered by me thinking about making a Tongshen conversion so :

Considering the 250W unit for MTB / gentle off road / fire road use - if needed can this be upgraded to the 350W unit or beyond via the firmware ?

What are these units like to pedal when the battery is not fitted ? Is there a freewheel / internal clutch or are is it hardwork pedalling the motor around.

Any recommendations for a UK supplier of motor / battery - There are so many options out there and I would be after 34Teeth (or smaller)

Many thanks

 

[Benjahmin]

All geared hub motors have a clutch. When new there may be some initial stiffness but should freewheel well. However there will always be the feeling of cycling through treacle when power goes off simply becauase you get used to the feeling of the assistance. Many mistake this for motor resistance.
A motor marked 250w will be legal. This does not mean it is limited to 250w, it is merely the 'continuous rating'. The actual maximum power delivered will depend on the controller. i.e. A 10A max 36v controller will give you 360w on top setting. A 15A max controller will give you 540w at 36v.
None of this will damage the motor because these are maximum values and will only be seen when going up hill in max setting.

A rear wheel geared hub would suite your usage well.

 

[matthewslack]

A 34 tooth chainring on a TSDZ2 will give poor chainline in the lower gears. The standard ring is dished so that the teeth are more onboard than a flat ring, but that does not work below 42T.

For lowish MTB type gearing, try a cassette with 50T or so lowest gear.

 

[AndyBike]

Considering the 250W unit for MTB / gentle off road / fire road use

lol, dont know where you got this info. 250w is more than enough for offroad adventures.
From a snow covered near cliff face start, sheet ice flats to rocky single track and tight forestry nobody could ever say the megavalanche is a gentle bimble.

The start doesn't look that steep, but here's a much better perspective.
If only I was 20 years younger
At the start you can be moving at 100km/h

 

[Woosh]

Considering the 250W unit for MTB / gentle off road / fire road use - if needed can this be upgraded to the 350W unit or beyond via the firmware ?

you should consider the 48V TSDZ2 with throttle instead of 36V and no throttle.
The TSDZ2 mechanical motor is the same for all versions. Tongsheng fit different set of LCD and controller according to customers requests. Basically, they have two controllers: with and without throttle, and each controller has two working voltages, 36V and 48V. The LCD's working voltage is either 36V or 48V to suit the controller, you can't change the combination later. 48V version gives you 30% more torque.
If you reprogram the motor at a later date, you are still restricted by your original choice: 36V or 48V, with or without throttle. The controllers are designed for 10A continuous working current, that is 360W for the 36V and 480W input power for the 48V. Given that the yield of conversion from electrical to mechanical is about 80% and 10% friction load in the mechanical bike, the 36V can deliver 250W continuously, so it's their base model.
If you extend the current to more than originally set (about 15A max), you will shorten the life of your motor. My other remark is about buying the model with throttle. Climbing steep hills without a throttle is such hard work that you'd wish you had bought one with a throttle in the first place.

 

[Mendip99]

Many thanks to everyone with the feedback.
I will have a rethink based on the points raised !