What can I do to correct my chainline?
 

I wouldn't ask if it didn't seem like I had no options.

I have ...

a 17t Surly track cog, 3/32
a Surly track hub
a Sugino RD Crankset
a Sugino 103mm bb

My chainline is at about 45mm in the front and 42mm in the back... I think. I can't move my chainring to the inside of the cranks, I can't move the hub spacers around, I can't get a smaller BB that would make enough of a difference to correct it. What can I do?

I have the same setup except I have an EAI cog. Mine seems to run fine, although I know of others that have the RD cranks and their setup is very noisy.

If you can't move your chain ring to the inside of the spider... then you either have to get a wider bb to allow for the inner placement... or, well there is really nothing else.

103bb is the smallest bb possible iirc... and if you can't move your chain ring to the inside, then your last option is to go for a different set of cranks... or trying a 107mm bb with your ring on the inside... but you still will be 1.5mm off instead of 3mm.

What direction is your cog installed?

Put a bottom bracket spacer between your cog and hub. Just make sure you have enough threads to get your lockring on.

use a smaller chainring?

This is the only solution out there other than A. just dealing with it, or B. moving the chainring to the inside and doing a different BB or some spacers up front. If you do the spacer out back, the Surly lock ring with the weird bevel thing helps you get a little more thread engagement, though it probably doesn't matter.

http://www.treefortbikes.com/imgDsp....&tw=300&th=350


I love that Sugino got up one morning and went, "You know, we could fix the chainline on the single speed RD today, or we could anodize them in Carebear colors." Which did they do?

http://www.thebikebiz.com/photos/TRK-CR-SUG05-2.jpg

Forget RD's for SS/FG use, get the XD, the Andels, or some nice road stuff.

did anyone every ask sheldon about the rd chainline problem? :(

I have the the same combination which I pulled off my complete Steamroller (as purchased) and swapped onto a junk find 80s MBK. I was a bit disconcerted to find the disparity when I reassembled them myself.

it was close enough for a while after I put the chainring on the inside of the crank spider, but then after a later tear down, it occured to me to check the frame aligment ie. the centering of the seat & chain stays. It's a pretty simple exercise and allowed me to put the chainring on the much more aesthetically pleasing outer mount.

Quick URL check : http://www.sheldonbrown.com/frame-spacing.html specifically the section part way down on alignment symmetry. It made my chainline spot on.

good luck!

Alignment problems can exacerbate chainline problems (or fix them, for that matter), but the chainline of RD's on a 103 BB is still 45mm

BTW, Surly is aware of the issue and has gone on the record saying they basically don't care:
http://bikeforums.net/showthread.php?t=338855

you make me cry, my friend.

Would not recommend doing this. Take your cranks off, take the bb out, sell them on ebay and buy a crankset that doesn't blow.

Or get a longer bb and move the chainring on the inside.

I just bought these on ebay to replace the sugino RDs on my steamroller:

144 BCD (AWESOME!)
170 mm
$40

http://sultanofschwag.com/images/ebay01/DSCF5820.jpg

Anyone want some used RDs with bottom bracket? lol

I'll take that bb off your hands

that was frikkin funny

thanks bro

I'll bet your rear chainline is closer to 43.. Have you measured it? If you are within 2mm...who cares.
If you really are off 3 or more mm, the simplest solution is to rearrange spacers in your axle. You mentioned that you can't move your hub spacers around...why? If you have spacers, you can move them. If you only shift your hub a mm or two you won't even really need to redish your wheel, but you can if you want to.

On BB spacers?
Why not use a BB spacer? If there is enough threads, it's the quickest and cheapest way to solve the problem.

i've got some decent solutions here
 

i like the solution of putting in a longer bb and moving the chainring to the inside of the spider ok. i wouldn't mind putting in a new set of cranks. i could give my old crankset/bb to a friend who'd really appreciate them.

what combination of bb/cranks would give the most optimal chainline when used with a surly hub/surly cog?

thanks!

check sheldon's bb size database to find the correct crank/bb combo to achieve optimal chainline.

Operator: I gotta wait until my new stuff gets here, but I'll pm you when it does.