Jack Bissell wrote
> I have checked the Retro Raleighs site for help w/ dating my
> 753 Raleigh. According to their serial # info, my bike #SB 3628
> would be a 1983. Can anyone confirm/ deny this?
>
> Also, I'm tempted to ream the seat from 27.0 to 27.2--is that
> possible and acceptable w/ thin 'super-steel'?
If it's 27.0 now, then it's *probably* inch-dimension tubing, not metric, but you should check this before reaming. Older 753 frames were metric, yes even Raleighs, though I think the inch-based stuff was probably available by '83. Metric seat tubes are 28.0mm outside diameter; the ones based on a certain number of barleycorns laid end-to-end are 28.6mm (1-1/8"). Since paint adds a bit, metric will actually measure a tad over 28mm but it won't be over 28.2, so any decent vernier or dial caliper will tell the tale. Measure in a couple of places around the tube, as they can fool you by being slightly oval.
If it's 1-1/8", then 27.2 actually is most likely the proper size seatpost, and your frame may have been slightly damaged by putting too small a post in it. Try to spread the slot a bit by prying before reaming. I usually pry the slot a little too wide, to minimise the amount of metal removed right in the slot area, then let the pinch bolt pull the slot back closed.
If I'm right and this is a standard 1-1/8" 753 seat tube, the amount of reaming will be very little indeed, just truing up the hole, removing some distortion. The metal is not too hard for reaming, if you were worried about that (your comment about 'super-steel')
If it's a metric seat tube, 27.0 is already reamed a bit oversize, so don't even think about 27.2. I've seen it done, but I've also seen it break there because of it.
Mark Bulgier
Seattle, Wa
USA