Joined: Jul 2014
Posts: 1,397
Likes: 169
From: Milton Keynes, England
Bikes: 2.6kw GT LTS e-tandem, 250w Voodoo, 250w solar recumbent trike, 3-speed shopper, Merlin ol/skl mtb, 80cc Ellswick
I'd usually recommend a rear hub, but your tyres are too thin for any conversion, let alone a rear hub. Unless you want pinch flats every time you're out you'll want a tiny motor in the front wheel and a bottle battery on the down tube, with oversize tyres at least 1.5 ins.
Then after your first ride you'll realise you've got totally the wrong handlebars for the job.