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Chainline Problem or Normal Operation?....(10 posts)

Chainline Problem or Normal Operation?....asphalt assault
Apr 21, 2003 4:05 PM
I'm running Ultegra 2 ring in front to Ultegra 9sp rear along with Ultegra BB. I bought all the parts at the same time from a reputable Etailer and I doubt they sent me the wrong length BB.

When I'm in the small ring up front and the smallest or second smallest cog out back the side of the chain rubs on the inside of the big ring making some rather annoying noises. Is this fairly normal operation for the setup I'm running or should I be able to reach both extremes of my cassette with no problem while in the smaller of the two rings?...or am I cross-chaining and really should be in the big ring to achieve that ratio/cadence?

I'm comparing the operation to my MTB. I run 3 rings to 9sp rear and while I'm in the middle ring I have no problem reaching either end of my cassette. Some differences I can see on the MTB are that the rings are smaller diameter and (probably) the distance from BB to cassette on my road bike is shorter.

Anyway I'm wondering if I should have a longer BB spindle or if this is normal for my setup and I should be in the big ring when I'm at the smaller end of my cassette.

Thanks for your thoughts!
re: Chainline Problem or Normal Operation?....Live Steam
Apr 21, 2003 4:18 PM
I had the same problem with my fiance's Klein. Small/small rubbed the inside of the large ring. It is Shimano 105. I was able to compensate by off-setting the BB just enough to enable the chain clear the large ring, but she doesn't cross chain any more, any way :O)
re: Chainline Problem or Normal Operation?....cycleaddict
Apr 21, 2003 4:28 PM
"Steam--I KNEW you HAD to be a Shimano person!! That explains it all:)
OK buddy I have just about had enough of ...Live Steam
Apr 21, 2003 6:07 PM
heeheeheeheehee! We'll leave the acrimony for the non-cycling forum :O)

Actually I have Record on both of my bikes. I had the 105 from the AL TCR I originally had. Took it off and put it in a box. I used it to build up the Klein Quantum Pro I bought for my fiance. I am a Campy man all the way. At least we agree on one thing :O)

Sweeeeeet!!!!!!!!!! Thanks for the pix.......cycleaddict
Apr 21, 2003 7:03 PM
What kind of BB was that?....asphalt assault
Apr 21, 2003 4:52 PM
That you were able to offset it? I did that on my MTB but I have a Race Face BB and it's designed so you can adjust (offset) your chainline...I didn't think I could do that with my Ultegra BB.
What kind of BB was that?....Live Steam
Apr 21, 2003 6:11 PM
Shimano 105 BB.
Very normalMR_GRUMPY
Apr 21, 2003 4:55 PM
Some people get it on just the outer cog, while some get it on the outer two. Likewise, some people can go big-big without a problem, and some can't. Every brand frame is just a little different.
I don't hear where you actually checked the chain line.Kerry
Apr 21, 2003 4:56 PM
Nominal correct chain line has the middle rear cog dead center between the chain rings (sighted front to back with a good straight edge). If your chain line is not correct, you can space the BB to the right (1 mm spacer between the right BB cup and the frame. If your chain line is correct and you still have rubbing, you can space the BB to the right but you'll have sharper chain angles going to the bigger cogs. This may or may not be a problem for you. Most setups have this problem in at least the small-small combo with a 39/53 in the front.
re: Chainline Problem or Normal Operation?....wielerpret
Apr 22, 2003 4:09 AM
In the 'small front blade - smallest 2 rear blades' configuration it's normal to have some contact between chain and derailleur or for the chain to sound a bit strange. Your chain runs across the entire cassette and is pulled into alignment by the blades. It doesn't run straight enough (i.e. as parallel with frame as possible). Usually it should be possible to find an equivalent combination using the large front blade and e.g. the third largest rear blade. The combination you mention will also cause your drivetrain to wear sooner by the way. The handbooks don't recommend it.
Good luck. Luke. Amsterdam.