The P13, prior to 1971, used Reynolds 531 fork blades with the standard 45 degree bend, out of the box. They are designed for 27" rims (though early P12s and P13's from the '60s had shorter chainstays and fork blades, and were better suited to 700C's), and fitting 700C's requires loads of brake reach. Top tube braze-ons were fitted to the right side; makes mounting NR brakes a pain - and even with 27" wheels, you need a drop bolt on the back. Forget about NR's with 700C's.

This all-purpose road/touring geometry was handed over to the P15, which was essentially the same as the P13 with a NR triple crankset and a long cage RD. The "old" P13 geometry became the P10, with virtually no changes.

The new P13 introduced in 1971 (or somewhere mid-year) tightened up the chainstay and fork length for 700C's exclusively, and the stock brakeset became the Nuovo Record sidepulls (in the very last years, Weinmann 605's were optional). The top tube braze-ons were deleted in favor of cable clips. The fork rake was also revised to a much more gradual curve, similar to Italian machines of the era - I'm not sure if this was a bend available from Reynolds, or something done in-house.

That said, here's a shot of a '70 P13 (background) and a '72 P13 in the foreground - the fork rakes should be apparent, and are the quickest spotting detail. The P10 and P15 should be identical to the P13 in the background:



-Kurt