Bicycle Mechanics - Short chain length on a 1x7

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View Full Version : Short chain length on a 1x7


Philatio
01-15-08, 07:08 PM
I just put a new chain on my 1x7, and only measured once before I cut. I ended up one full link, one inch, shorter than my old chain. Shifting is fine.

When I'm on my 26T cog, the largest in the back, I'm right on the edge of it not having a full "S bend" as it passes through the two derailer pulleys. I can take a picture but really my question is this: if shifting is fine, could there be any other problem with the chain being too short?

I'm mainly worried about it wearing prematurely or something due to a higher tension, but it does seem that a single speed or fixed gear would be much "tighter" than this is.

Also, and I sort of am convinced this is all in my head, it seems like there is more resistance now then with the old looser chain. I've swapped back and forth with the old chain and tried to measure the deflection change among other things, but everything seems very subjective.


AndrewP
01-15-08, 07:59 PM
It should be OK if the jockey wheel cage is not against its hard stop. A new chain isnt that expensive, so may be worth the peace of mind while you are riding.

Bill Kapaun
01-16-08, 01:30 AM
It sounds like you are OK. The main concern about being too short is when shifting to the largest cog and not having enough chain, causing the deraileur to bend in ways it was not designed.
As long as you have "some slop", you're good.


Rowan
01-16-08, 02:33 AM
Actually, the problem is not so much the deraileur bending in ways it oughtn't, but total seizure of the transmission. If this isn't occuring in your biggest rear cog, then you really probably don't too much to worry about. Obviously, if the derailleur appears to be almost horizontal when in the big rear cog, you might be inviting trouble.

How did you measure it? Chainring to big cog and add an extra complete link? Was the one-inch (actually half a link) difference because you used a joiner?

rhenning
01-16-08, 07:24 AM
If you have a chain tool why not just add one link back in. It is not that difficult to do. Roger

tjspiel
01-16-08, 08:20 AM
Yeah, I've added links back in. If you end up with a stiff link, the chain tool I have (and I'm assuming any other decent one) has a separate place to put the chain so that tightening the tool a bit will loosen the link back up so it works as it should.

well biked
01-16-08, 08:21 AM
You could break the chain and then check to see if it's sized correctly:

http://www.sheldonbrown.com/derailer-adjustment.html#chain