Chain length

tunney

I fitted an ultegra chain to a DA rig at the weekend, I followed the Park instructions on chain length (Routed the chaing over the big rear and big front and not through the rear mech, where they touched I joined).

But the chain tension seems very very tight, power transfer is sweet but the top two on the back are unusable when big at the front. I know that this is expected but before I changed chain (and BB, chainrings and cassette) this wasn't an issue and 53x25 was my favourite gear.

Looking at the shimano instructions on chain length - they say when the rear mech is 90' to the ground - but do they mean the pulleys or the bar of metal between the pulleys?

http://techdocs.shimano.com/media/techdocs/content/cycle/SI/SI_5X90B/SI-5X90B-003-00-ENG_v1_m56577569830702204.PDF

Gavin

Did you follow step 5 ?

From the closet rivet, lengthen the chain by counting over an additional two rivets (two links), which is a distance of one-inch. Cut the chain at this point.

tunney

Gavin wrote: »

Did you follow step 5 ?

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tunney

that would be no.

IM0

tunney wrote: »

COOOOOOOOOOOOOCCCCCCCCCCCCCKKKKKKKKKKKKKKKKKKKKKKK.

yeah instructions work really good when you read them all

Murph100

Tunney,


Sounds like you didn't allow for the 2 extra links you must add on when using the Big Sprocket to Big Chainring method.


Ooops didn't hit save for 2 mins so slightly tardy post.

TinyExplosions

tunney wrote: »

that would be no.

Fecking freddish mistake to make.... Tunney, he knows about power, but not about chains :P

tunney

Murph100 wrote: »

Tunney,


Sounds like you didn't allow for the 2 extra links you must add on when using the Big Sprocket to Big Chainring method.


Ooops didn't hit save for 2 mins so slightly tardy post.

Yes I had thought it looked a link or two short. damn it, I've done this 100 times but normally I read all the isntructions before doing any repairs.

Murph100

This is the reason why I always run it through the RD and use small sprocket to small chainring until it just clears the RD, no adding links to forget that way !

tunney wrote: »

Yes I had thought it looked a link or two short. damn it, I've done this 100 times but normally I read all the isntructions before doing any repairs.

Single Malt

For shimano, the best way is small sprocket, large chainring. When the line through centre of jockey wheels is perpendicular to ground, chain length is bang on.

The large/large gets ideal chain length on SRAM (but SRAM is not too fussy)

The small/small gets ideal chain length on campy. (do not use this for shimano, as the chain will usually be a link too long)

Correct chain length, following the manufacturers instructions, has HUGE impact of shifting smoothness and quality.