Ken Cox

BlastRadius wrote:

"If its really only 1mm, it could be your eyes playing tricks on you."

I believe my eyes often do play tricks on me.

What a neat tool, and a great explanation of how to use it.

icithecat

Ken. Anybody at work use a laser level or laser straightedge?

jondrums

I presume you probably have a pair of calipers somewhere you could borrow? Well here's my process for chainline tuning...

Measure the following things:
Tcr (thickness of chainring)
Tcg (thickness of cog)
Df (Distance between left side of seat tube and outside face of chainring)
Dr (Distance between inside face of right dropout and outside face of cog)
ODst (Width of seat tube = outside diameter of seatpost)
Wd (Width between inside faces of both dropouts)

chainline_rear = Wd/2 - Dr - Tcg/2
chainline_front = Df - ODst/2 - Tcr/2
compare

buy the right width bottom bracket spacer(s) if the front chainline is less than the rear chainline, if its the other way, flip the chainring to the inside of the cranks and then buy the necessary spacer...

Much simpler than it sounds.
jon

Ken Cox

Well, I stopped by the competitor's bike shop, where I had bought my commuter some time ago, and he took a hard look at my chain line.
As politely as he could, he told me I had as good a chain line as it gets and if I started messing with it I would only make things worse.

Oh.

Gonna impose reality on me, eh?

Still, I have learned a lot from this thread.

Thanks.

When I build my all-Italian bike two years from now all of this information will come in handy.

jondrums

ken - I say bull. if you want to be a perfectionist about your chainline, don't let anyone rain on your parade. yeah its useless to get that last .5mm but if it makes you feel better, for god sakes do it! I do, because I like workin on my bike.

Wambat

Previous model pistas have some chain noise issues, related to the stock chain and chainring. https://www.bikeforums.net/showthread...ht=pista+noise don't know if it's different or the same for the '05s.