Shimano 105 Rear Derailleur

[benni.123456]

I have an Shimano 105 rd 5600 rear derailleur. I’m wondering what cassette I can fit, with how many gears and teeth. I currently have a 12-25 and wanting to go bigger. I have also heard about a extension arm to fit bigger cassettes.

Any help is welcomed.
Thanks

 

[DCLane]

That's a short cage derailleur, so you could run an 11-28 but no wider.

The alternative is a long cage derailleur or an extender. They would allow you to go to a 36 tooth but you're likely to need a longer chain.

 

[Jameshow]

Yeap 28 or a long cage mech and new chain.

You don't need to fit a 105 rear mech anything 10spd or less (not tiagra 10 SPD will work)

 

[benni.123456]

Okay thank you, do you know if I would need a new derailleur if I wanted to run a 11-28 11 speed?

 

[Jameshow]

Okay thank you, do you know if I would need a new derailleur if I wanted to run a 11-28 11 speed?

You would need 11spd rear mech, shifters chain etc.
Stick to 10 SPD.

 

[T4tomo]

Okay thank you, do you know if I would need a new derailleur if I wanted to run a 11-28 11 speed?

5600 is 10 speed. Why are you asking about 11 speed compatibility?

 

[fossyant]

You can get the 5701 GS (medium cage) 10 speed mech and that will do a 34T (officially 32T but I'm running a 34T on one wheelset.

https://www.sjscycles.co.uk/derailleurs-rear/gs-shimano-105-rd5701-10-speed-rear-derailleur-black/

 

[benni.123456]

You would need 11spd rear mech, shifters chain etc.
Stick to 10 SPD.

Thank you so much, I’m new so thanks for helping.

 

[Ajax Bay]

https://www.cyclechat.net/threads/shimano-105-rd5600-capacity.248390/
See last post in thread above (by @Yellow Saddle )

Current RD will be fine with 28t largest, and that cassette would give a gear 12% longer. I recommend the OP just goes there (new cassette and chain (latter one link longer maybe) and see if that is sufficient.
For a larger largest than 28t, OP needs GS rather than the current SS: eg this one:
https://www.ebay.co.uk/itm/266938227251? £35 ono

 

[Alex321]

Okay thank you, do you know if I would need a new derailleur if I wanted to run a 11-28 11 speed?

You would need new derailleur, shifter, cassette and probably chain.

All the bits have to be designed for 11 speed for it to work - the distance between sprockets is slightly different, so the shifter needs a slightly different "pull" for each gear change.

 

[Grant Fondo]

I have an Shimano 105 rd 5600 rear derailleur. I’m wondering what cassette I can fit, with how many gears and teeth. I currently have a 12-25 and wanting to go bigger. I have also heard about a extension arm to fit bigger cassettes.

Any help is welcomed.
Thanks

I'm swapping out ultegra 6800 11-28 for bigger cassette, so rear mech, cassette, chain available 11sp though so you would need new shifters??