Cassette Changeover query

[Archibald]

probably a stupid question, but if you changeover your cassette and the ratio is different, do you need to adjust your rear derailluer at all?
I've gone from a 12-21t to a 12-27t (not ****ing out, just happened to be based on availability) and will be increasing the smaller chainring size soon to increase ratio.

I'm thinking not, as the derailluer only moves across to line up the rear sprockets, so should be fine regardless of sprocket size, but just want to make sure

 

[Hawkwood]

probably a stupid question, but if you changeover your cassette and the ratio is different, do you need to adjust your rear derailluer at all?
I've gone from a 12-21t to a 12-27t (not ****ing out, just happened to be based on availability) and will be increasing the smaller chainring size soon to increase ratio.

I'm thinking not, as the derailluer only moves across to line up the rear sprockets, so should be fine regardless of sprocket size, but just want to make sure

You might need some extra chain, plus if it's an oldish chain it might not run well on the new cassette.

 

[on3m@n@rmy]

probably a stupid question, but if you changeover your cassette and the ratio is different, do you need to adjust your rear derailluer at all?
I've gone from a 12-21t to a 12-27t (not ****ing out, just happened to be based on availability) and will be increasing the smaller chainring size soon to increase ratio.

I'm thinking not, as the derailluer only moves across to line up the rear sprockets, so should be fine regardless of sprocket size, but just want to make sure

You might need some extra chain, plus if it's an oldish chain it might not run well on the new cassette.

I had a 53-39 chainrings and went to 12-27 cassette to handle some long bodacious mountain terrain. Then back to my 12-23. I did not have to adjust the read derailluer or add chain length. I have since gone to a compact crank (think it's 52-32), and if you do that you will have to remove a fair amount chain. I don't recall exactly, but I must have pulled out around 3 to 4 inches... I remember thinking it was a lot more than I was expecting to remove. It does not shift as smooth on or off the 2nd and 2rd small sprockets in back, but it works good enough. Keeping the chain lubed well helps.

 

[tubularglue]

throw cassette on. If questioning, ride it down to ur local shop and ask if chain length is doable. Make sure you ask the mechanic who looks as old as dirt'


voila !



nothing better than new chain/cassette combo - like warm butter

 

[TheDude]

throw cassette on. If questioning, ride it down to ur local shop and ask if chain length is doable. Make sure you ask the mechanic who looks as old as dirt'


voila !



nothing better than new chain/cassette combo - like warm butter

Agreed - but don't add length if you don't need it. A chain that is long enought to use up all of the take-up in your derailluer is also likely to slip off in hard shifts on bumpy roads. I pick a chain length that does not allow for X-chain on largest sprocket to large chainring, but lets me get to about the 3rd from largest sprocket. I find everythign smoother and more reliable. My gues is that you won't have to change length. Unless your chain is rather new, I would change it. Measure it for stretch if you are not sure.

 

[Archibald]

ah, didn't think of chain length.
currently no sign of stretch - just needs a bit of a clean...

cheers folks.

 

[Boeing]

You might get some top pully rub in the 27. short cage DR will stretch the spring and allegedly limit the life of the DR but throw it on

you might want to replace the chain with the cassette anyway and cut to length