48v 250w motor

[stodd]

Woosh sell that kit with various options and will give good pre-sales advice and post-sales support.
https://wooshbikes.co.uk/cart/

You might save a bit by buying the various bits separately but with the kit you have the knowledge that all the bits will work together and good help with any issues; all especially useful for a first conversion.

[hemo]

Only Woosh bikes sell a TSDZ 250w kit afaik, they have a custom spec'd motor from Tongsheng so as to comply with UK 250w rating.