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Old 03-03-21, 12:54 PM
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dddd
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Bikes: Cheltenham-Pederson racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.

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It's common and normal for the chain to rub against the big ring when running in the small-to-small gearing.

Novices often use that gear because of a dislike of selecting a precise lever position while riding, or because of their failure to keep the shift lever tension screw tensioned.
So it's only the cheap bikes that typically use longer bb spindles to gain chainring clearance, at the expense of straighter chainline when running big-to-big.
I would argue that the big-to-big gearing combination is much more useful and so would say that your chainline is healthy. The rubbing would be even worse if you were using wider vintage chain, which you aren't.

It's also not uncommon for the shift lever to need to be moved to it's travel limits when using modern derailers, and wider cassettes than the bike's original freewheel.
Modern derailers, mostly starting with Shimano's first "600 SIS" derailer of the mid-1980's, require more cable and lever throw to move a given distance sideways. This is called a lower actuation ratio and makes shifting more precise (though which also can make for sluggish shifting feel until one adapts to the greater movement needed at the lever).

There are also different make/model shift levers having larger diameter cable spools that will move more cable if needed.

Consider yourself lucky if the narrower 10s chain never "skates" between the two chainrings, which are spaced for older, wider chain. It's fixable if it does, by beveling the non-drive side of the tips of the small ring's teeth, and/or by bending all the teeth slightly toward the drive side.
I will say though that steel chainring's teeth generally give better shifting than equivalent alloy chainrings of the same vintage.

Last edited by dddd; 03-03-21 at 01:03 PM.
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