Shimano SP-7400-B, Dura-Ace
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Category:  Seat Posts
Name:  Shimano SP-7400-B, Dura-Ace
Brand:  Shimano
Primary Group:  Dura-Ace 7400
Model:  SP-7400-B
Years:  1988 - 1995
Country:  Japan
Weight:  261 grams
Added By: JFischer on 10/13/07
Updated By: rswift on 12/19/14
Additional Photos - click for full size
Shimano SP-7400-B, Dura-AceShimano SP-7400-B, Dura-AceShimano SP-7400-B, Dura-AceShimano SP-7400-B, Dura-AceShimano SP-7400-B, Dura-AceShimano SP-7400-B, Dura-AceShimano SP-7400-B, Dura-AceShimano SP-7400-B, Dura-Ace
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MarkingsDura-AceMaterialAluminum
Shaft DesignAeroSaddle Attachment StyleSingle bolt
Saddle Attachment Bolt Size(s)6mm Allen KeyOverall Length 200mm
Max Height Setback 19mm
General Information

The 7400-B is Shimano's "aerodynamic", semi-oval, shaped Dura-Ace post. It's design and shape is a variation on the Deore AX seatpost released as a touring grouppo in the early 1980's. There are 5 major parts to the 7400-B post, the mast assembly, two clamp pieces, the fastening bolt and a steel spacer. The mast assembly is a true work of art. Machined of a single piece of billet aluminum, there is a great deal of intricate workmanship involved in its oval-aero shape. The interior of the mast is bored out to reduce the weight, leaving a 2.7mm wall thickness and sturdy top section to support the clamp pieces. The clamp pieces rest in a machined cradle that permits the clamp angle to rock and be cinched at different angles. A slot milled through this clamp support allows the fastening bolt to pass up through the bottom of the cradle into the upper clamp piece. The fastening bolt rises through a chrome steel spacer (the spacer has a 9 gram weight) located beneath the bottom of the clamp saddle. This spacer fits in a half-rounded hollow and has flat ends. At the front, near the top, there is a 3mm steel hex bolt which pushes or holds the spacer and the fastening bolt in a fixed position. This small bolt can permit tiny adjustments in this micro-adjusting seatpost. Setback measured at 19mm on a 73º seat tube. The fastening bolt is chromed steel with a 6mm hex head. It's 8mm by 1mm thread pitch with a 34mm length and a 17.5 gram weight. The clamp pieces are both cast of aluminum alloy. The upper clamp piece resembles the Ritchey and Campy upper pieces, having threads for the fastening bolt to grip and four points of saddle rail contact. Each side of both clamp pieces offer 1 5/8" of rail contact. The lower clamp piece is cast with a hole for the threaded bolt anchor from the upper piece to pass into, as a "key" locking the pieces in place. There are knurles on the lower side which grip against the top of the clamp saddle on the mast when tightened. The entire post has a satin polished finish, with the name, in Black, etched on edge in the front. With the clamp perpendicular to the mast section, the center of rail to end of tube length is 200mm. The weight of a 27.2mm 7400-B post is 261 grams. The Shimano SP-7400-B Dura-Ace post is made in Japan, and is available in, 26.2mm, 26.4mm, 26.6mm, 26.8mm, 27.0mm, and 27.2mm sizes.

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Component VariationsView Detailed List  Manage Variations
Variations of Component exist (Component is 1 of 2)BrandGroup
Shimano SP-7400-A, Dura-AceShimanoDura-Ace 7400
Component Groups
Primary Group NameBrandQuick InfoBrowse Group Components
Dura-Ace 7400Shimano1984 - 1995, Road RaceView 40 Components
Details:  

Shimano's top of the line race quality component group in the mid 80's through the early 90's. The 7400 series Dura-Ace group saw several interations including the introduction of 6 then 7 and finally 8 speed SIS shifting. Eventually upgraded with 7410 parts before finally being completely replaced with 7700.

Dura-Ace was developed to give the professional racing cyclist a fraction-of-a-second advantage that can spell the difference between victory and defeat. Advanced functions like 8 speed SIS, Super SLR brakes and Shimano Total Integration provide the most refined feeling of control available in a group today. Ultra high-precision mechanisms, quality materials and rugged construction assure that Dura-Ace takes all the punishment that pro-level road racing can dish out. (1991 Dealer Manual).

Brand Information(click to expand)

Shimano Model Number Prefix List:

BB Bottom Bracket BL Brake Lever BR BRake
CB Coaster Brake CJ Cassette Joint CN ChaiN
CP Chain Protecto CR Chain Ring CS Cassette Sprockets
DF chain DeFlector DH Dynamo Hub FC Front Crank
FD Front Derailleur FE Fork Ends FH FreeHub
FS Front Suspension HB HuB HD HanDle bar
HP Head Parts (Head Set) HS Handle Stem IF Inter-3 Freehub
LP LamP MF Multi Freewheel PD PeDal
RD Rear Derailleur RH Rollerbrake Hub RM RiM
RR ReflectoRs RS Rear Suspension SB Shift Brake lever (Nexus, ?)
SC Speed Calculator (cycle computer) SF Single Freewheel Freilaufritzel SG Speed chanGe hub
SH SHoes SL Shift Lever Schalthebel SM SMall parts
SP Seat Post SQ Seat Quick release SS Single Sprocket
TL TooL WH WHeel ST Shift Brake Lever (STI, Rapid Fire, etc)
 
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