I have a Decathlon Rockrider 5.2 and I'm planning to replace my current crankset with a Shimano TOURNEY FC-TY501 6/7/8-speed Square Crank 48/38/28.

Would like to know if this compatible with my bike. Currently here's what I know about the specs:

Rear Cog: 32/11 (8 speed)

Rear Derailleur: Shimano Altus Rd- ct95 8 Speed

Front Derailleur: Shimano C050 Top Swing Sis

Crankset: SR Suntour PFF 42/32/22

Top view of front crank and derailleur Side view of front crank Close-up of front derailleur

  • Do you plan on replacing the bottom bracket also. In my experience the bottom brackets used with Shimano cranks are not the same length as those used with Suntour cranks.
    – mikes
    Commented Mar 9, 2021 at 22:38
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    Yup exactly, will be getting a new BB.
    – Abhinav
    Commented Mar 9, 2021 at 22:40
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    What bicycle? Going to a larger crankset may not work because the front derailleur can't be moved high enough, and the location and shape of the chainstay may interfere with larger chainrings. Pictures of the front derailleur and the chainstay/crankset clearance from above or below would help. Chainline changes might also cause problems. Commented Mar 9, 2021 at 23:35

1 Answer 1


FD-C050 is profiled for a 42. This degree of mismatch is usually not enough to keep it from working at all, but it's not necessarily negligible either. The tighter curve may force the FD to need to be mounted higher than ideal, which can result in inferior contact with the chain and/or gaps that allow derailment. An FD is a cheap enough part that I recommend just getting one that you know will play nice with your 48 and be done with it.

As pointed out in the comments, it's possible to run into frame clearance limitations with the bigger rings.

Total capacity is 43 on RD-CT95 so that's fine.

If the chain is sized right for your current crank, it will be too short for the new one.

SI info

  • Thanks Nathan for your response
    – Abhinav
    Commented Mar 10, 2021 at 11:37

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