Chain Line

"Graham" <[email hidden]> schreef in bericht
news:[email hidden]...
Maybe a dumb question, but how do I know if I have the correct chain-line
on a singlespeed bike.

Graham

;-))))))))

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Posted by news://news.nb.nu

Graham said:

Maybe a dumb question, but how do I know if I have the correct
chain-line on a singlespeed bike.

See: http://sheldonbrown.com/chainline

Sheldon "Straight Ahead" Brown
+------------------------------------------------------------+
| People who go broke in a big way never miss any meals. |
| It is the poor jerk who is shy half a slug |
| who must tighten his belt. --Robert A. Heinlein |
+------------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Graham said:

Maybe a dumb question, but how do I know if I have the correct chain-line on a singlespeed bike.

Graham

The chain stays on and doesn't rub anything but the cogs.

I'm pretty sure sheldon has this on the site, but basically, you position yourself behind the bike. Sight down the chain line, trying to centre the chainring in your line of sight . The chain should track directly back to the cog from the ring. Also, when backpedalling and pedalling, there should be no noise.
As insurance, I like to mount two old "guard" cogs on either side of the drive cog, to discourage the chain from unshipping. This is due to the lack of an overpriced chain tensioner, and vertical dropouts.

--
--------------------------
Andre Charlebois
AGC-PC support
http://agc-pc.tripod.com
BPE, MCSE4.0, CNA, A+

"Graham" <[email hidden]> wrote in message news:[email hidden]...
Maybe a dumb question, but how do I know if I have the correct chain-line on a singlespeed bike.

Graham

Graham said:

Maybe a dumb question, but how do I know if I have the correct chain-line on a singlespeed bike.

Graham

Go to Sheldon Brown's site and read up.

FYI, my SS chainline measures 2mm off- 45 in front and 43 in back. But
sighting and with a ruler it looks spot on, and I've never had the
chain come off. Then again, maybe my frame is out of alignment.

gtgelliot-<< Maybe a dumb question, but how do I know if I have the correct =
chain-line on a singlespeed bike. >><BR><BR>

Chain line should be parallel to the top tube.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

Qui si parla Campagnolo said:

gtgelliot-<< Maybe a dumb question, but how do I know if I have the
correct = chain-line on a singlespeed bike. >><BR><BR>

Chain line should be parallel to the top tube.

Yes, but that's not easy to determine directly, is it?

I set my chain-line on my fixie by observing how the cogs entered the gaps
in the chain, i.e. making sure that they weren't closer to one side plate
than the other. Perhaps that only worked for me because there is a tiny
bit of play between chain and cogs for me.

--
Benjamin Lewis

Seeing is deceiving. It's eating that's believing.
-- James Thurber

Graham said:

Maybe a dumb question, but how do I know if I have the correct
chain-line on a singlespeed bike.

Measure it with a pair of vernier calipers, or put a known straight edge
(e.g. the sharp side of a metal rule) on the chainring and see if it
also touches the sprocket. 1mm out is probably OK for a bushingless
chain, but more than that gives you a "crackly"-running chain and
potential other problems.

Chainline, FWIW, is the distance of the middle of the cog teeth from the
centre line of the frame.