i just put on a new chain. how do i know what the correct length should be? i can’t really measure from the old chain, because i just switched back from my compact to the regular crank, and i switched the rear cassette to a smaller one…
i put the new chain on, and even though there’s no real “slack”, it just doesn’t seem to be as tight as it should… does that make any sense?
Put your chain on the smallest cog and smallest chainring. If the rear derailleur is rubbing on itself it is too long. There is a screw that adjusts tension on the der. If this doesn’t give oyu enough play you need to remove a link. I usually match up my old and new chain and remove links to fit. Then install. Good luck!
There are a few ways to measure–all end up similar. The bottom line is that the chain has to be long enough to wrap the large chainring with large cassette cog without pulling the derailleur too tight and short enough that when on the small chainring/small cog that the derailleur cage can pick up the slack. I actually run the chain a couple of links longer than the minumum length to allow using a larger cassette if needed. A couple of extra links will still usually be well within the RD capacity.
http://www.parktool.com/repair/readhowto.asp?id=26
From Sheldon Brown:
“The best technique for setting chain length is to thread the chain onto the large/large combination, without running it through the rear derailer. Mesh the two ends on to the large chainwheel so that they could be connected (outer link meets inner link), then make the chain one complete link (one inch) longer than that. In almost all cases, this will give the optimum length.”
well simple
biggest coq front biggest cog rear
3 chain links from the place the chain leave the cog from the rear to the derr wheel ,and the chain then in full tension make sure you have at least 3 links not 2 or 2 and half or one no 3
thats the most ideal
.
What about the Shimano directions which state something like this: When in the large chainring and smallest cog, the r drlr pulleys will be in a straight line with the axle of the wheel.
I’ve been using this method for years…do ya’ll think that’s correct…I’m guessing Shimano does:)
dk
That method works fine.
Wrap it around the big/big without running it through the derailleur. Then ADD two links(one inner and one outer, which equals ~1". Cut and join there. Make sure you have an inner link on each end though, so you can use the outer plate to connect them.
i think this method is great too. everyone else has these complicated ways of doing things