This Olmo Serial Number Dating Registry records Olmos with original dated bike parts or provenance, and sometimes only with decals, in order to attempt correlating an Olmo serial number to a year or year range. Absence of a question mark means there is some certainty about a bike's year or a range of years, established by parts dating, provenance, etc., or by preceding or following dated bikes.
Later Olmos with date-able elements are actively added, as well as pre-1978 Olmos. A TIPO RONDINE decal may or may not appear on some older Olmo bikes, and refers to the Agrati AM lugs, with 'rondine' meaning 'swallow.' Some older Olmos have the ornate Agrati lugs which Emilio Bozzi sold as Brianza sportiva lugs; the accompanying Agrati rear dropouts are stamped with a scalloped back.
Campagnolo crank arms have a date code starting in 1973, consisting of a diamond (1970's) or circle (1980's) with a number in the center denoting the last digit of the year of manufacture, and then in 1985-9 with square and number in the center: 11 = 1985, 21 = 1986, 31 = 1987, 41 = 1988, 51 = 1989 plus some other examples.
Olmo Gran Sport Miguel//bikemig/bikeforums.net: Swallow rondine lugs with no seat lug side slot; forged Campagnolo dropouts; chrome head lugs, fork crown, stay and fork ends, and seat tube panel; Falck tubing PARTS: Magistroni steel crankset with alloy 49-46 chainrings; Ambrosio Champion stem and handlebars; Olmo headset and seatpost collar; Weinmann Vainqueur 999 'engraved' centerpull brakes with single spring; Campagnolo shifters, Gran Sport front and rear derailleur with cable adjuster; Campagnolo Record high flange hubs; Regina freewheel (14-26); Sheffield Sprint pedals; saddle not original DECALS: OLMO GRAN SPORT on downtube, with OLMO in white letters; CAMBIO CAMPAGNOLO winged wheel at top of seat tube DATING: Campagnolo hub locknuts are (19)60; Weinmann Vainqueur 999 center pull brakes changed from one spring to two springs in December 1962, according to Weinmann catalogs; Campagnolo Gran Sport rear derailleur lost its cable adjuster around 1960. Olmo Ron Titensor/CR: May not have swallow rondine lugs in spite of decal ORIGINAL PARTS: "...completely originalincluding fenders, steel stamped Olmo hubs w/ wingnuts, steel stem and bars, steel Magistroni 49/47 crank set.Simplex (made in Italy) derailleurs, the front being the Competition and the rear the Juy-51.Olmo Rondine David Rapley/Racing Bicycles: 100 years of Steel, pp 100-101.Google Books Swallow rondine lugs with seat lug side slot; chrome head lugs and fork crown; chrome stay and fork ends; Campagnolo Cambio Corsa dropouts and fork ends BRAZE-ONS: top tube brake cable ORIGINAL PARTS: 4 speed Campagnolo Cambio Corsa; Campagnolo hubs; Nisi 36 hole rims; Magistroni Senior five pin crankset with 48t chainring; Olmo headset; Brooks B17 saddle; Balilla brakes; Silver blue paint DECALS: decal remnant on top of seat tube; otherwise, none DATING: book author says bike is 1948, from an Olmo team mechanic Serial Number 889 1946-1951? ] bg.legendary.bikes/e Bay: may not be an Olmo; seller does not say it is an Olmo in the listing and description; does not have swallow rondine lugs; chrome forks; Campagnolo Cambio Corsa dropouts and fork ends REPAINTED...Olmo [Professional Deluxe] Rydor Bike Shop: Swallow rondine lugs with no seat lug side slot; chrome head lugs, seatlug and bottom bracket; chrome forks; chrome panel on seat tube; red chromovelato BRAZE-ONS: top tube brake cable ORIGINAL PARTS: "first generation Campagnolo alloy cotterless crank set ...
Campagnolo bar end shifters, high flange hubs, steel derailleurs and a TTT alloy adjustable stem." Mafac Racer 'Dural Forge' brakeset.
NOT ORIGINAL DECALS: head tube and seat tube decals are Olmo 'Lazy L' star logo.
OLMO with red background on left side of top tube is unfamiliar on other Olmos.
Bike has later Olmo decals added on seat tube, top tube, and down tube. Olmo [Rondine] jjokcha/e Bay: Swallow rondine lugs with no seat lug side slots; chrome head lugs and fork crown; chrome stay and fork ends; Campagnolo Cambio Corsa dropouts and fork ends; no top tube brake cable braze-ons; 5558 stamped on side of seat tube below seat lug [cannot see if there's a serial number stamped behind the seat lug; seller says the frame size is 56 cm] DECALS: Head badge and seat tube decal with Olmo 'Lazy L' star logo; OLMO in white block letters within white oblong outline on downtube Cannot see Serial Number 1948 Olmo [Rondine] Swallow rondine lugs with no seat lug side slots; chrome head lugs and fork crown; chrome stay and fork ends; Campagnolo Cambio Corsa dropouts and fork ends; no top tube brake cable braze-ons REPAINTED Serial Number 108 1950s? Olmo Sport Guillermo Pelegrina//docbilly/bikeforums.net: Swallow rondine lugs with no seat lug side slots; seat post clamp bolt at front top side of seat lug; forged long horizontal Agrati dropouts with scalloped backs; Headbadge is Olmo 'Lazy L' star logo; shifter braze-on at front of top tube, with cable internal to top tube; generator/dynamo bracket on right front fork; [Rear brake cable runs inside top tube?
Olmo city bike ORIGINAL PARTS: Olmo branded handlebars and stem, brake levers, crankset, hubs, headset, seat post collar. ]; Pump pegs on back of seat tube; Chainguard mount on rear of right chainstay.
Olmo [Gran Sport / Professional Regular] Roger Barrett: Swallow rondine lugs with no seat lug side slot.