Ride a '73 PX10E converted to a fixie, and love it. The stepped pattern on the lugging is indicative of a UO-8, however (Gordon P's post). Earlier PX10s had a more ornate, swirly lug pattern. I've also got a PKN10, a PFN10, and a UO10; they all ride great. An old UO8 would make a good around town beater bike, though I'd make sure the rims are alloy and not steel first... steel rims are not noted for their braking ability. In fact, they're not noted for braking at all.
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