Looking for confirmation before ordering

So there is this 10" wheel hub motor I'm looking at fitting to an e300. Seems like it will fit but as I am learning I want to make sure.
http://www.ebay.com/itm/High-quality-10-10inch-24V-500W-1200rpm-electric-scooter-hub-motor/162597813771


Also I wanted to make sure my math was right about theoretical top speed.


10 (d)*3.14*1200(rpm)*60(m) = 2,260,800

2,260,800/(5280*12) = 35.68mph?

Thanks for the help.

I think your math is correct, but there's no way you're going to hit 35mph on a 500w motor.