[QUOTE=miamijim;14337523]

"No offense but almost everything in your post is incorrect or heresay.....

1. Frame geometry: There's no reason why some Pugeots have steep geometry and others don't. The year of manufactur has nothing to do with it.
2. Number of digits in serial number = decade built. Urban legend. Sometimes it holds true, sometimes it doesn't. I have pictures of a late 60's PX10 w/ a 5 digit number.
3. Plenty of '72's have Nervex fancy lugs. 2 of mine did.

Here's the breakdown on the OP's bike:

Very simply it's a '70-'73 PX10. Peugeot moved the Reynolds decal to the downtube in '74 so it pre-'74. Square or what I'll call 'Type II' decals are found primarily on '70 and later bikes. So there it is, '70-'73."



Good points, Jim, about the handlebars and rims having date stamps, I forgot about the bars, but some of the later ones also have a date on the stem quill.

I don't use catalog info at all, but had read the CR list info in the past, and understood (agreeing with you here) that early-70's PX10 serial numbers were unreliable.
I rely mostly on the rear derailer date as the best indicator, and as I recall, the bars tended to be dated very closely to the derailer anyway.

I'm sure that there was definitely a reason why some PX10's have steep geometry and others don't. It was a huge decision in making such a profound change!
It also seems logical that after the change in geometry was made, that all same-sized PX10's were made to the same dimensional specs for a good period of time. BTW, my PX10LE with W.C. stripes still has the 76+ degree geometry. I have no dated parts for it (unless the Phillipe bars are dated) and the sewup rims aren't stamped with anything.

I assume that the dates on the components are consistent within several months of when the frame was made and the bike assembled. There was little reason for them to stockpile years worth of parts when production was humming along, and even if they made huge bulk contract purchases then the parts would have likely been delivered as needed.

While I don't think that they jumped back and forth with their geometry over any short interval, the date of change could have been mid-year, and could have been months different from when they changed lugs, printed catalogs, or celebrated New Year's day.

The bikes with 1972 components and Nervex Pro lugs were likely justmade at a different time of year than those plain-lugged versions.
Oh, and what type of geometry did your 1972's with fancy lugs have?