Changing cassette gearing

cabbieman

Senior Member
Hi. Can I swap a shimano Sora 13-25 cassette for an 11-30/32? Do I need a new chain? It's a secondhand bike purchase for my niece and I don't think she could cope with the hills on a 25. Any suggestions ?
 

Sharky

Guru
Location
Kent
The old chain/cassette is bound to be a bit worn, so probably prudent to fit a new chain as well.

What's on the front?
 
OP
cabbieman

cabbieman

Senior Member
I'm asking, just awaiting a reply. Is the rear derailleur designed to just take up the slack when changing gears? I'm never sure about changing cassette sizes
 

vickster

Legendary Member
I'm asking, just awaiting a reply. Is the rear derailleur designed to just take up the slack when changing gears? I'm never sure about changing cassette sizes
You may need a different rear mech for the new cassette and a longer chain. Need to know what's there currently
 

Cycleops

Legendary Member
Location
Accra, Ghana
You'll need a new chain but mech will be able to cope up to 34T. It is designed to take up extra chain length .
Formula for chain is big cog front to big cog rear omitting the Derailleur plus two links.
 

Cycleops

Legendary Member
Location
Accra, Ghana
Not necessarily, could be a short cage derailleur.
brand_thumb_shimano.jpg
Shimano Sora R3000 9 Speed.

Sora R3000 9 Speed rear deailleur from shimano. Sora rear derailleur feautre a light action shifting with a wide link design give incresed rigidty for better shifting. The 11 tooth pulley wheels help to increase chain life and reduce chain noise. Available in Black compatible with 9 speed drive trains only.

Use Road
Mount Direct Mount
Max Sprocket Size 34 tooth
 

si_c

Veteran
Location
Wirral
View attachment 460091
Shimano Sora R3000 9 Speed.

Sora R3000 9 Speed rear deailleur from shimano. Sora rear derailleur feautre a light action shifting with a wide link design give incresed rigidty for better shifting. The 11 tooth pulley wheels help to increase chain life and reduce chain noise. Available in Black compatible with 9 speed drive trains only.

Use Road
Mount Direct Mount
Max Sprocket Size 34 tooth
There are two variants for the RD-R3000, the GS (long cage with Max 34t) and the SS (max 32t), all of which is irrelevant because the OP is running Sora 3500 and both the SS and GS variants have a max 32t sprocket, the difference between the two is the total capacity - meaning the GS version can be used with a triple at the front and the SS can't.
 
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