Diamond Back Large Pro Specifications

Part	Details
Finish	Chrome (with blue components) or flamboyant red or blue (with gold components).
Frame	Diamond Back 4130 chrome-moly. ( Koizumi )
Fork	Diamond Back 4130 alloy. chrome-moly. Dual position (leading axle and centerline) dropouts. ( Koizumi )
Handlebars	Diamond Back chrome-moly, butterfly.
Grips	OGK, Mach model vinyl.
Headset	Tange MX-2
Stem	Diamond Back by Sugino, chrome-moly shaft and bolt, forged alloy head.
Rims	Araya 7C side-polished (on chrome bike); Araya 7X gold, no side-polish (on red or blue bike)
Spokes	080/36, chrome-plated.
Hubs	Suzue alloy.
Brake calipers	Dia-Compe, front and rear.
Brake levers	Dia-Compe.
Brake pads	Dia-Compe.
Cables	Dia-Compe.
Tires	Diamond Back Skinwall Knobbies (by IRC).
Pedals	Diamond Back BM10 (by MKS).
Cranks	Sugino, forged chrome-moly one-piece,175mm.
Bottom Bracket	Tange
Front Sprocket	44T Sugino alloy, chrome spider.
Rear Sprocket	16T SunTour, easy-off freewheel.
Chain	1/8 inch, Chrome (HKK)
Seat	Diamond Back by Kashimax.
Seat Post	7/8″ Fluted aluminium alloy.
Seat Post Clamp	SunTour, aluminium alloy.

Diamond Back Large Pro Frame and Forks

The large pro came in 2 colours and chrome. Described as flamboyant red and blue, the paint has a metallic finish to it. The large pro came with double drop-out forks which comprise of dropout that has a forward and centre position.

The centre position provide unpopular and was discontinued when the next generation of Diamond Back pro models, the Pro Kit, was brought out.

Large Pro Identifying characteristics

Identifying characteristic	Looks like
Large gusset, diamond cutout
Serial numbers are found on the rear, non-drivemdropout and are in the Koizumi standard 6 digit format followed by a Kanji (baseball). Serial numbers will begin 9, 0 and 1. This means 1979, 1980, 1981
Loop tail

• Serial number are found on the rear, non-drive dropout and are in the Koizumi standard 6 digit format followed by a Kanji (baseball).
• Serial numbers will begin 9, 0 and 1 – 1979, 1980, 1981 only
• 1981 models will have a 1 followed by A, B or C, for January, February, March.
• By April 1981 the model was replaced with the Senior Pro.
• Original bikes came with double drop out forks, as seen above.
• See details on that page for more.
• Loop tail
• Large gusset (3 TIG welds)

Additional Information:

• Model production run was from 1979 to April 1981