Btwin 520 flat bar cassette upgrade question

[Dacker9]

Hi
2017 Bwin 520 flat bar hybrid bike has 12-25 rear cassette and triple front crank
Can I ask, what is the maximum cassette I can fit without changing the rear mech, thanks

[gregoryoftours]

You need to check the Max rated sprocket size for your rear derailleur model (code on the back of the parallelogram if it's Shimano). You can usually go at least 2 teeth over this rating. Also the Max capacity must not be exceeded. This will differ between the long and short cage versions (GS and SS respectively) You may need a longer chain.

[Dacker9]

Thanks for your helpful reply
I’ve not actually got the bike yet, I have seen it advertised and am thinking of buying it...all I know is that the current cassette is sora 9 speed 12-25 with sora derailleur, I just wondered if I could fit a cassette with 28 or 30t using the same derailleur and perhaps just getting a new chain, thanks

[A1anP]

My wife has the same bike. When we bought it in Decathlon, we asked for an 11-32 cassette to be fitted. It works just fine so there will be no problem with fitting a 28 or 30.

Later on, I swapped out the 30 tooth chainring for a 26, so now she can ride up the remaining few hills that she used to get off and push up.

Enjoy your new bike
Alan

[mattsccm]

I would bet than any bike with a triple chainset would take. at least a 28 if not 32. Just the logic of the design.

[Dacker9]

Hi
Many thanks to you all, for your kind and helpful replies, you have answered perfectly, best wishes