Diamond Back Pro Large Chrome with Blue Components

Diamond Back Large Pro

Diamond Back Large Pro, from early 1980s brochure

Diamond Back Large Pro Specifications

FinishChrome (with blue components) or flamboyant red or blue (with gold components).
FrameDiamond Back 4130 chrome-moly. ( Koizumi )
ForkDiamond Back 4130 alloy. chrome-moly. Dual position (leading axle and centerline) dropouts. ( Koizumi )
HandlebarsDiamond Back chrome-moly, butterfly.
GripsOGK, Mach model vinyl.
HeadsetTange MX-2
StemDiamond Back by Sugino, chrome-moly shaft and bolt, forged alloy head.
RimsAraya 7C side-polished (on chrome bike); Araya 7X gold, no side-polish (on red or blue bike)
Spokes080/36, chrome-plated.
HubsSuzue alloy.
Brake calipersDia-Compe, front and rear.
Brake leversDia-Compe.
Brake padsDia-Compe.
TiresDiamond Back Skinwall Knobbies (by IRC).
PedalsDiamond Back BM10 (by MKS).
CranksSugino, forged chrome-moly one-piece,175mm.
Bottom BracketTange
Front Sprocket44T Sugino alloy, chrome spider.
Rear Sprocket16T SunTour, easy-off freewheel.
Chain1/8 inch, Chrome (HKK)
SeatDiamond Back by Kashimax.
Seat Post7/8″ Fluted aluminium alloy.
Seat Post ClampSunTour, 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.

Diamond Back Pro (Large) with in the 3 main colour ways. Double Drop out forks can be seen in the foreground. These were discontinued shortly after as riders preferred the forward position and never used the rear.

Large Pro Identifying characteristics

Identifying characteristicLooks like
Large gusset, diamond cutoutLarge gusset Diamond Back
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
Photo of a DiamondBack BMX frame Koizumi serial number
Loop tailLooptail BMX example
  • 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

Serial number tools

Our serial number checker can identify most Japanese Diamond Back between 1979 and 1983. New bikes are being added regularly.