Need a new freewheel (for Genesis Day One) and I bought the last Shimano one from CRC for about £20.

Are they all the same / compatible though? Is this £10 BMX one at PlanetX the same fit?

http://www.planetx.co.uk/i/q/SKSHOEMBMX/shimano-dx-bmx-freewheel

Thanks!

Yup, they’re all the same threads as old skool screw on freewheels.

they appear to have taken a picture of the back of it. one presumes it has lugs for a freewheel tool so you can get it off again…

I think the DX Bmx ones are a bit tougher.
This may or may not be true.

I had a Shimano one on my commuter. It wore out in less than a year. I replaced it with a Whites Industries. More expensive, I grant you, but much better quality and also has a nice all-important clicky freewheel 🙂
Rode it all through last winter without any kind of maintenance and still going strong

Bit more here