Monday, August 20, 2012

Details...

It's the little things that you don't notice that sometimes make the biggest difference.  Or they don't really make any difference at all, but the way it goes together and sets up gives you infinite pleasure.  Once upon a time, steel frames were made with 1 1/8" diameter down tubes.  They also had shift bosses on the down tubes because that's where shifters were mounted.  Then when shifters were moved to the brake levers, frames still had bosses on the down tube so these handy little bolt on cable stops were created that covered the shifter bosses and matched the curve of the 1 1/8" diameter down tube.  

At some point, down tubes increased to 1 1/4" but the down tube boss shape didn't change.  The radius of the stop stayed at 14.3mm.  Big deal, you say.  Well, yeah.  When the shift boss was bolted to a frame with a 1 1/4" down tube, the top and bottom of the boss can dig into the down tube.  Not bad, but bad enough to potentially chew up some paint and just not look "right."  So what to do if no one is going to tool up to make shift boss stops for 1 1/4" down tubes?

Reshape the shift boss stop, that's what.  It's easy.  The way I do it is fix a file in the vise, remove the adjusters and, holding very firmly, draw the stop back against the file knocking off the edges of the stop.  Now, it will fit nice and flush against the down tube.  Remember to dab some grease on the shift boss and bolt threads before installing.  There, now you can rest easy.  

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Draw the boss across the file.

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The stop on the left before modification.  Stop on the right after being modified.

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Fitting nice and flush with the down tube.

(What's playing:  KWMR Release Me)

2 comments:

Mauricio Babilonia said...

Great idea, thanks! And better still, one could use the convex side of a half-round file.

blackmountaincycles said...

Yes, that would work too. I've tried that and found that the flat side is a bit quicker, not that I'm looking for the easy way out.