Changing from 12-27 to 11-30

Sportiveman

Hi Guys,
I have currently on my winter bike a 9 speed compact running 12-27 I want to change the cassette to a 30 low gear so thinking of getting a 11-30 cassette will this be straight swap or will chain need an extra link as extra teeth than now ?

peanut

the difference in sprocket diameter is negligable so you current chain should be fine provided it fits properly now.

You don't say what chainset you have fitted ? there is more than one way to skin a cat as they say.
Instead of changing your cassette with any issues that might cause with the rear mech hanger length, chain etc why not just fit a smaller inner ring ? 38T is minimum on a 130BCD and 33T minimum on a 110BCD compact chainset

You might also find changing your outer chainring to a 48T or 46T (micro ) will give you much better gearchanges between outer and inner rings and give you the option to stay in the outer ring longer .
Anyone that thinks this is crazy on a road bike might look at Tony Martins setup which is an 11-34T cassette "
https://www.youtube.com/watch?v=7tVihsWlpFU

if you imput your chainset and cassette into Sheldon Browns gear calculator you'll be able to mess about with your ratios to your hearts content and look at all the options. I usually select the 'inches' option rather than the ' ratio' as i find that easier to visualise. I reckon about 3" is a nice gear change and anything less than about 2.5" is hardly worth considering really.

http://www.sheldonbrown.com/gear-calc.html

milemuncher1

Sportiveman wrote:

Hi Guys,
I have currently on my winter bike a 9 speed compact running 12-27 I want to change the cassette to a 30 low gear so thinking of getting a 11-30 cassette will this be straight swap or will chain need an extra link as extra teeth than now ?

Check your drivetrain capacity is okay first. Then make sure your chain is long enough.

There are lots of calculator sites on the net.

itboffin

do they make a 30T for 9 speed?

Sportiveman

peanut wrote:

the difference in sprocket diameter is negligable so you current chain should be fine provided it fits properly now.

You don't say what chainset you have fitted ? there is more than one way to skin a cat as they say.
Instead of changing your cassette with any issues that might cause with the rear mech hanger length, chain etc why not just fit a smaller inner ring ? 38T is minimum on a 130BCD and 33T minimum on a 110BCD compact chainset

You might also find changing your outer chainring to a 48T or 46T (micro ) will give you much better gearchanges between outer and inner rings and give you the option to stay in the outer ring longer .
Anyone that thinks this is crazy on a road bike might look at Tony Martins setup which is an 11-34T cassette "
https://www.youtube.com/watch?v=7tVihsWlpFU

if you imput your chainset and cassette into Sheldon Browns gear calculator you'll be able to mess about with your ratios to your hearts content and look at all the options. I usually select the 'inches' option rather than the ' ratio' as i find that easier to visualise. I reckon about 3" is a nice gear change and anything less than about 2.5" is hardly worth considering really.

http://www.sheldonbrown.com/gear-calc.html

I have a compact sora 34/50 chainset . I want to change it so have a 30 t large sprocket for the hills as hilly where I live

Sportiveman

itboffin wrote:

do they make a 30T for 9 speed?

Yep a 11-30 hence my post

Fypo

Assuming you have a sora derailleur it apparently can take up to a 32 cassette, and I wouldn't think you would have to add any links so it should be a straight swap. When you next replace your chain though you might want to add a link or two if it is a little short.

pblakeney

Fypo wrote:

Assuming you have a sora derailleur it apparently can take up to a 32 cassette, and I wouldn't think you would have to add any links so it should be a straight swap. When you next replace your chain though you might want to add a link or two if it is a little short.

I'd check before heading out though. It can cause serious damage if the chain is too short.

Frank Wilson

I went from 12_27 to 11_32 (Sora) and changed the chain.

lesfirth

PBlakeney wrote:

Fypo wrote:

Assuming you have a sora derailleur it apparently can take up to a 32 cassette, and I wouldn't think you would have to add any links so it should be a straight swap. When you next replace your chain though you might want to add a link or two if it is a little short.

I'd check before heading out though. It can cause serious damage if the chain is too short.

Agreed. You might not intend to use big sprocket/big chainring but if you do, you will know very quickly if your chain is too short .

Sportiveman

I have a new chain on it unfortunately it has a ultegra 6600 rear mech . So swap it over and give it test ride to see if it works ok ?