Removing MTB Cassette

[grellboy]

My son's chain keeps slipping so I was going to replace it and the cassette but just had a quick look before work and it seems different to road cassettes I am used to. Seems like no lock ring. So - two questions - Can I Just remove it with a chain whip and wrench and when replacing it, does that mean I have to get a cassette with the same fitting? (in other words - no locking?)
Thank you
Dan

 

[figbat]

It looks like it’s a freewheel rather than a cassette - you’ll need a freewheel tool to unscrew it from the wheel. Refitting can be done by hand, with the pedalling action fully tightening it.

 

[T4tomo]

https://www.halfords.com/cycling/bike-maintenance/bike-tools/halfords-freewheel-tool-164131.html

you need one of these, they are often barstewards to get off. top tip, attach tool, you can secure tool by replacing quick release skewer / re threading nut onto axle, put tool in vice, use the wheel / tyre to turn the freewheel off the tool.

 

[Ajax Bay]

https://sheldonbrown.com/k7.html
Procure a freewheel (all the same thread, so choose by sprocket number and range).
Do not use your cassette lockring tool, even if it 'sort of' fits (same number of splines but different depth).
As @figbat says, freewheel tool needed, plus a large spanner to fit, plus an extension bar to cope with @T4tomo bar steward torque requirement, if the 'tool in a vice and turn the tyred wheel' method (mental gymnastics to turn the right way) doesn't sort it.

 

[Roseland triker]

Yep tool in vice.
Don't twist the rim through the spokes.it may be seriously tight.