Looking for a big flywheel

[Roboteernat]

Simple look in gumtree or e-bay for an old spin bike. Will already have a chain or belt + bearings. Got one with broken peddles on gumtree for £10 before.

this, yes!

i used a spin bike fly wheel as my spinning disk on my heavyweight robot in series 6, although the chain came off on the first hit, it did work well in testing, plus the added benefit of being on a clutch meant i had some protection of the motor... although it didnt get used!