@Billy
When you say dirt track does that mean unmade track where a mountain type bike would be required?
How many miles would you want to cover between charges, do you want a throttle too or just pedal assist, How fast do you want the bike to go assisted (legal limit in UK is 25KMH I believe although it’s very easy to change the limit on many of the standard ebikes available), what degree of your riding will be hills and how steep are they likely to be and finally what will the kit your carrying plus you weigh?
For what you have to spend it’s possible that you will get a lot more for the money buying a kit and fitting it to a standard bike, or, if you’re not too concerned about the street cred of the bike brand or in need of high end components, a bike sold by someone like ‘Woosh Bikes’ in Southend.
Woosh are very responsive to messages, offer lots of good advice to potential purchasers plus allow a decent test ride if you’re nearby plus their bikes provide good value with excellent after sales.
I’ve just converted my bike using one of their rear wheel hub motor kits, it was simple to do and seems very good so far.
Hub motors last for a very long time generally, however, they are not best choice for every type of riding, lots of off road bikes now have crank drives which I understand respond in proportion to the effort you put in and make steep Hill climbing easier (not tried one).
I’ve previously owned an electric Brompton and it was a great little bike but they are very expensive for what’s effectively adding a kit, it’s a lot cheaper to convert a Brompton yourself.
Good luck whatever you decide to buy.
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