Chain Length

[slowmotion]

I've always used this online calculator. It seems to have worked with a number of chainring/cassette combinations....

http://www.machinehead-software.co.uk/bike/chain_length/chainlengthcalc.html

My attitude is that if it's not making some horrible graunchy noise, it's probably quite happy. Mind you, my bike is pretty filthy.....

 

[autolycus]

Interestingly, this calculator allows extra for an oversized derailleur but unfortunately doesn't indicate what that means. I assume it means 'large' (?)

The other formula i've seen makes no such allowance. And of course the method of wrapping the chain large to large bypassing the derailleur doesn't either.

I'm quite new to this, but it seemed to me intuitively that the length of the rear derailleur must surely have a bearing on the length of chain required. Perhaps some more experienced member can confirm or refute?

 

[Pale Rider]

I have gone from a 27 to a 25 cassette.

That should help you go a bit faster, what will you be using as a climbing gear?

 

[subaqua]

why did you not measure it against the chain that was coming off then remove 1 link ? anyway glad you got sorted

 

[Ajax Bay]

the length of the rear derailleur must surely have a bearing on the length of chain required.

Not really. The length of the RD cage allows more to be 'wrapped, which is useful for a triple set up (eg 52-42-28) and a fairly wide cassette (say 12-30). The length of the chain required stays the same: large to large plus 2 (see discussion above). If you made it large to large plus 3 a long cage would cope (depending on capacity needed) but with no advantage.

 

[Ajax Bay]

why did you not measure it against the chain that was coming off then remove 1 link ?

This only works if the chain being removed was the correct length. And the OP went from a largest sprocket 27t down to a 25t. Does that need a whole (1") link pair shorter than before? Chain only goes round half the sprocket (at a time) remember.

 

[ianrauk]

That should help you go a bit faster, what will you be using as a climbing gear?

Just have to use a bit more oomph to get up the hills

 

[beastie]

Just replaced my cassette and chain. I have gone from a 27 to a 25 cassette.
Using the Zinn method of chain length calculation, ie Chain around large cassette and large chain ring + 1 complete link (the KMC quick link as half of a 1 link), but it looks a little too tight in this configuration (large/large, not that I use large/large much anyway)

What does the panel think?

View attachment 132283

I like the rims Ian, what are they please?

 

[ianrauk]

I like the rims Ian, what are they please?

Velocity V Deep 30mm as supplied by DCR Wheels.