Shimano Dura-Ace 7400 7401 7402 7403 7410 Series Road Component System 1984 – 1996

The year was 1984. I was only 14 and riding a beat up Raleigh Grifter around the estate. My parent’s shed was my workshop and I was kept busy fixing the bikes for all the local kids. My own bikes were fitted with names such as Sturmey Archer, Simplex, Huret and Weinmann. At the same time, unknown to me, two giants of the cycling world were about to go head to head for market supremacy. In the red corner, fighting out of Italy were Campagnolo, the makers of beautiful looking and precisely engineered components that graced the bikes of the professional peleton; they were up against Shimano in the blue corner, the Japanese corporation often only known for freewheels, hub gears and fishing reels.

This is a slight departure from my normal ramblings about with the Specialist Bicycle Development Unit (SBDU). I do this from time to time, especially when I’m researching a build. Next up for me is SB6560, a Panasonic 531c 1984 Services des Courses that I’m hoping to get on the road in 2018. I want to build this with a period specific Dura-Ace 7400 group. I know that building these bikes with anything other than Campagnolo may attract some criticism, there will be some who insist that these frames are built with either Nuovo or Super Record, but my advise is that it is your bike and your build, do what you want, there is no right or wrong way.

I wrote a small blog post a while ago that gave an overview of Dura-Ace 7400, but now I need to get down into the detail to make sure I get the specification correct. So in my usual OCD style, I’ve taken this further than I needed to and I’ve ended up hopefully providing an overview of Dura-Ace through it’s various iterations from 7400 in 1984 to the end in 1993-1996 with 7410.

A little bit of history… (and probably a short ramble too)

Winding the clock back just over a decade from 1984 to 1973, before I even started school, things had already begun to simmer when both companies launched their flagship groups; with Campagnolo it was the first time we heard the name Super Record and with Shimano it was a similar first appearance of a well known name, with their Dura-Ace Road Ensemble.

Campagnolo released Super Record on the back of their huge success and reputation. The innovations of Tullio Campagnolo, who started the company 40 years earlier, became part of the mainstay of the bike component industry. Although Shimano had been established as a company under the name of Shimano Iron Works twelve years before Campagnolo, they never appeared to achieve the same prominence as Campagnolo or many of the other component manufacturers of the same era.

However, Shimano were a slow burner, they were constantly growing and developing new technologies and advancing ideas. If you look through the 1975 Shimano catalogue, you can see it is packed full of products that you might be mistaken for thinking are current technologies. Shimano Positron, an early indexing system using a push/pull solid cable, auto-adjust caliper brakes, internal hubs with automatic gearing, automatically adjusted cable operated disc brakes, hydraulic disc brakes, and of course, different types of multiple freewheel… in fact, the freewheel was the first product Shimano produced back in 1921.

Their 1978 Bicycle Systems Components catalogue gave an insight into how rapidly Shimano were growing as a company, and how the professional use of Shimano components was on the increase.

In the spring of 1978, Shimano advanced things further with the introduction of more new technologies including the Freehub, and the launch of Dura-Ace 7200 EX.  During this time it was clear that they were building a ‘System’, not just parts, they were developing a series of components designed to work together in the most efficient way. The principle Shimano were working with was that each part should be designed to work together, parts shouldn’t just be a collection of individually designed items. Parts such as the Uni-Glide (UG) chain was designed to work with the teeth of the UG sprockets, which were ‘twisted’ to run parallel with the chain as it moves from high to low gear; the ‘W-cut’ teeth of the chain rings designed to ease the UG chain to climb.

While making components perform and interact better together, Shimano also improved the overall design of individual items. The freehub is an example of how the effort to improve the design of the bicycle hub fixed so many issues with a conventional dished wheel and freewheel setup.

By 1980, Shimano had moved on again with Dura-Ace 7300 AX which was a completely different way of thinking about cycling components, their technology and bike/human performance. 7300 AX ran along side the conventional 7200 EX road group. In the 1981 Shimano Bicycle Systems Components catalogue published in December 1980, Shimano showed us the DEORE Touring Ensemble, followed up in 1982 with DEORE XT and the use of the words “Off Road”.

1984 was the year that Shimano would come of age. While I was messing with Sturmey Archer toggle chains and struggling with cotter pins, Shimano introduced the Dura-Ace 7400 Series, and with this, component design and technologies moved into a new era.

So where am I going with this..?

You may be able to guess that I’m a fan of Shimano, I’ve put a bit of a bias slant onto this blog post. I would be an equal fan of Campagnolo if they hadn’t have taken their eye off the ball and rested on their history and prominence. While Shimano’s growth was rapid, Campagnolo appeared to stand still. Shimano would not only pull up side by side with Campagnolo, they would start to forge ahead and leave Campagnolo with the only option available to them of having to design parts to try and keep up with the pace set by the ever growing Japanese corporation.

I think it is only fair to look at some of the things that Campagnolo did with their components in the same 1973 to 1984 period. Here is a little potted history gathered from some of the more popular Campagnolo sources and timelines…

• The word ‘Brev’ was replaced with ‘Patent’
• A new, shorter frame end was introduced
• The Portacatena (chain holder) system was developed
• Design changes were made following a mandate from the Consumer Products Safety Commission
• Parts in the existing Super Record group received a face lift, known as 2nd Generation
• Development of a 6 speed freewheel started in 1980/81
• Several promotional items including a belt buckle, a corkscrew and nutcracker were made
• BMX components were introduced four years after Shimano introduced their MX parts
• A steel axle ‘SL’ pedal was added to the Super Record group
• The 2nd gen Super Record TI BB was removed and replaced with the existing Steel Record BB
• The 50th Anniversary Super Record group was introduced in a limited supply
• A lightened Nuovo Record Steel headset was designed
• A 7 speed version of their freewheel was introduced but required a 130 OLN frame
• Super Record brake arms and fastenings had a face lift

It does demonstrate my point that while the giant was sleeping, the underdog came racing past. Campagnolo’s approach seemed completely different. Parts such as their rear derailleur were beautiful, but they weren’t designed to work in integration with any specific freewheel or chain. Their own freewheel was made of aluminium and titanium, it had it’s own specific toolkit and wasn’t a part that you would fit on your ‘regular ride’ road bike.

Campagnolo introduced the RECORD (corsa) group to trade shows at the end of 1984, they later described it in their own words “C-Record made its debut in 1984 featuring a group of components with unprecedented aesthetics. The smooth and aerodynamic shapes of every detail, and particularly the lines of the Delta brakes, were unique. In the long run, this new groupset was acknowledged as one of the most attractive and desirable in the history of cycling“.

Undoubtedly the RECORD group was beautiful to look at, but it had issues, particularly with early Delta brakes. The lack of integrated design, which Shimano had designed into their systems, was evident with Campagnolo. Their attempt at indexing with the Syncro lever created headaches for many mechanics and riders with compatibility charts and inserts. Something as simple as Shimano’s gear lever with a ‘click’ would cause Campagnolo a problem, Shimano’s index system (SIS) comprising gear lever, index mechanism, cable, chain, derailleur, hub and cassette worked perfectly straight out of the box.

From this point on, Campagnolo were playing catch up and were following Shimano’s lead. The 80s popularity with mountain bikes put a Shimano derailleur on almost every MTB. If it wasn’t a Shimano derailleur it was Suntour, until that giant eventually had to give way too. Deore XT and a whole range of other Shimano groups were domineering. Every person coming into cycling in the 80s, typically younger people getting their first mountain bike knew nothing else other than Shimano. Campagnolo were nowhere in the mountain bike scene and were struggling to keep the pace in the road bike market.

Dura-Ace 7400 Timeline…

This is quite difficult to put together; the parts in this range are now over 30 years old (at the time of writing this in 2017) and factual information is difficult to come by, spec sheets are dropping off manufacturers websites and spare parts lists are disappearing every year. There are also several 7400 timelines on various sites and blogs but I’ve found some errors in a few of them so I haven’t used them as a source, I’ve kept my info, the stuff I’m going to write below, to any available Shimano documentation, fact sheets, catalogues and dealer manuals. Even these are not without issue as I’ve found the occasional typo and anomaly. However, they are direct from the manufacturer so I’m using them.

This is a first attempt, and very much an overview. There is so much detail in this group over the years but I can’t possibly cover it all. I already know there are gaps, especially in the later period, but I’ll update the timeline as and when I find the info to plug them.

** Any reference to component codes and product dates are taken directly from Shimano’s own publications **

** This timeline focuses on how each lineup appeared at their launch – newer features may have appeared before the next significant release **

1984 – Shimano Dura-Ace 7400 6 Speed (SIS)

The original incarnation of Dura-Ace 7400. The image above appeared in the January 1985 catalogue called “New Dura-Ace The Unlimited Challenge”. It was 6 speed Uni-Glide (UG) group with options for a freewheel or freehub and Cassette. The group was equipped with non-aero brake levers and standard side pull short reach calipers. Pedals came with Shimano clips and cleats. The down tube levers offered either 6 speed SIS shifting or a switch to operate a standard friction setup. The minimum tooth on the freewheel was 13T, if you wanted a 12T option you would need to use the freehub and cassette alternative. I haven’t yet found any reference to a specific model UG chain, various sources simply list a Shimano UG or Sedisport chain, so at this point, I can’t see a specific CN-7400 in the line up.

Each part was referenced as ‘7400’. Here are some details I’ve been able to put together using Shimano documents.

Rear Derailleur	RD		RD-7400	Min 12T Max 26T Max Diff 26T
				189 grams 6.7oz
				Double Servo-Panta Mechanism
				Centeron Guide Pulley
				Sealed Mechanism
				Sintered Alloy Guide Pulley Teeth
				Titanium Coated Pulley Bushing
				Brass Bushings & Stainless Steel Link Pins
				Double Spoke Barrier
Freehub	FH/HB		FH-7400-R	438 grams 15.4oz Rear 6sp w/o sprockets
			HB-7400-F	228 grams 8oz front
				Rear 126mm Front 100mm
				28 32 36H
				Sealed Mechanism, Lubricating Ports
				Uniglide Teeth Cassette Hub
				Uni Balance System
Hub	HB/HB		HB-7400-R	315 grams 11.1oz Rear
			HB-7400-F	228 grams 8oz front
				Rear 6sp 126mm Front 100mm
				28 32 36H
				Sealed Mechanism, Lubricating Ports
Cassette	CS		CS-7400	12-17T, 13-18T, 13-21T, 13-23T, 13-26T
				Champagne Gold Finish Sprockets
				Threaded Sprocket 12T-16T
				Spline Sprocket 13T-32T
Chain	CN		Uniglide (UG) or Sedisport	No specific mention of ‘Narrow’
Multiple Freewheel	MF		MF-7400 (6 Speed)	360 grams 12.7oz (13-14-15-17-19-21T)
				Champagne Gold Finish
				New Uniglide Teeth
				Sealed Mechanism
				Lubricating port on Freewheel Body
				13T Minimum
				13-18T, 13-21T, 13-23T
Shift Levers	SL		SL-7400 BCAI (Side Band)	72 grams 2.5oz (BCAI)
			SL-7400 FCAI (Side Braze)	Light Allot Buff Finish Lever
			SL-7400 FCBI (Mount)	Steel Fixing Bolt, Clamp
				Shimano Index System One Touch Switch
				SIS and Friction System
				28.6mm (1 1/8″) Clamp Diameter
				Sealed Mechanism
				Human Engineered Design
				Non Loosening Mechanism
Front Chainwheel	FC		FC-7400 (Double)	637 grams 22.5oz 42-52T 170mm
				Light Alloy Anodised Crank C/Ring
				Light Alloy Etching Anodised Crank Cap
				1/2″x3/32″ Chain
				Inner 39-46T (46 from March 85)
				Outer 48-54T (54 from March 85)
				165, 167.5, 170, 172.5, 175
Bottom Bracket	BB		BB-7400 (BB Parts)	314 grams 11.1oz
				Steel Fixing Bolt
				Nickel Cr-Mo Axle
				68-W-112
				70-W-113
				Sealed Mechanism
				English French Italian Cups and Axles
PD	Pedal		PD-7400	372 grams 13.1oz (Pair inc L Toe Clip)
				34 degree Clearance
				Nickel Cr-Mo Axle
				Chrome Toe Clip M L LL
				9/16x20TPI
				French M14x1.25
				Compound Type Needle and Cup/Cone
Front Derailleur	FD		FD-7400-B Band	Max 15T
			FD-7400-F Braze	93 gram 3.2oz (Band)
				28.6mm clamp (1 1/8″)
				Helicoil Secured Cable Fixing
Brake Levers	BL		BL-7400	216 grams 7.7oz (pair)
				Light Alloy Anodised Finish (Lever/Bracket)
				Stainless Lever Axle
				Anatomical Design
Brake	BR		BR-7400	355 grams 12.5oz (F&R 49 Type)
				Light Alloy Anodised Arch
				Steel Pivot Bolt and QR
				Light Alloy Colour Anodised Shoe Holder
				Front Double Lock Nut Type
				Eccentric Type QR
Head Parts	HP		HP-7400	113 grams 4oz
				Titanium Plated Lower Cone
				Eng/Ita BC1x24T 30.2 26.4
				French M25xP1.0 30.2 26.4
				Sealed Mechanism

1986 – Shimano Dura-Ace 7401 7 Speed (SIS)

The actual date that the 7401 components appeared is difficult to pin down, so far I haven’t found an exact period. The general thinking is 1987 but the Shimano Bicycle Components catalogue dated December 1986 listed the new 7401 components.

The move from 6 speed Dura-Ace 7400 to 7 speed 7401 only involved changes to a handful of parts. A new rear derailleur RD-7401, new shift levers SL-7401, a new 7 speed freewheel but keeping the MF-7400 code (there was now an MF-7400-6 and MF-7400-7). Likewise, there was a CS-7400 6/7 cassette. The freehub also remained the same and retained the FH-7400 code but appears as FH-7400 6/7. This is the first time I’ve seen reference to the CN-7400 Narrow UG chain. 7400 6 speed documents have only listed a “UG chain”.

The diagram below shows that a hub could be switched from 6 speed to 7 speed by moving a 1.6 mm washer from one side of the axle to the other. An anomaly I found in the dealer catalogue was mention of a rear hub with a 130 mm OLN dimension, but the exploded view diagrams list the same 137 mm axle (126 mm OLN) for both 6 and 7 speed.

Although it has a new reference of RD-7401, very little actual changed to the rear derailleur. The Titanium coated pulley bushings on the RD-7400 became Ceramic on the RD-7401 model. The weight increased by approx 16 grams.

Shimano also took the opportunity to introduce two new components, the PD-7401 clipless pedal and the BL-7401 aero brake lever. The BR-7400 brake caliper remained the same but received an updated brake shoe holder design. All other components remained unchanged and retained the 7400 code.

Rear Derailleur	RD		RD-7401	Min 12T Max 26T Max Diff 26T
				205 grams 7.2oz
				Double Servo-Panta Mechanism
				Centeron Guide Pulley
				Sealed Mechanism
				Sintered Alloy Guide Pulley Teeth
				Ceramic Pulley Bushings
				Brass Bushings & Stainless Steel Link Pins
				Double Spoke Barrier
Freehub	FH/HB		FH-7400 6/7	438 grams 15.4oz Rear 6/7sp w/o sprockets
			HB-7400-F	228 grams 8oz front
				Rear 126mm 130mm*? Front 100mm
				28 32 36H
				Sealed Mechanism, Lubricating Ports
				Uniglide Teeth Cassette Hub
				Uni Balance System
				1/2″x3/32″ Narrow UG Chain
Cassette	CS		CS-7400-6/7	(6sp) 12-17T, 13-18T, 13-21T, 13-23T, 13-26T
				(7sp) 12-18T, 12-21T, 13-21T, 13-24T, 13-26T
				208 grams 7.3oz 6sp 13-21T & Spacer
				221 grams 7.8oz 7sp 12-21T & Spacer
				Champagne Gold Finish Sprockets
				Threaded Sprocket 12T-18T
				Spline Sprocket 13T-28T
Chain	CN		CN-7400	Narrow Type Uniglide Chain
				Bushingless Design
				Boron Finished Link Pins
				1/2″x3/32″
				Nickel Finish Roller Link/Pin Link Plate
Multiple Freewheel	MF		MF-7400-6 (6 speed)	360 grams 12.7oz (6sp 13-14-15-17-19-21T)
			MF-7400-7 (7 speed)	367 grams 12.9oz (7sp 12-13-14-15-17-19-21T)
				New Uniglide Teeth
				Sealed Mechanism
				Lubricating port on Freewheel Body
				12T Minimum (7 Speed)
Shift Levers	SL		SL-7401 BCAI (7sp Band)	65 grams 2.3oz (FCAI)
			SL-7401 FCAI (7sp Braze)	Light Alloy Buff Finish Lever
			SL-7401 FCBI (7sp Mount)	Steel Fixing Bolt, Clamp
				Shimano Index System One Touch Switch
				SIS and Friction System
				28.6mm (1 1/8″) Clamp Diameter
				Sealed Mechanism
				Human Engineered Design
				Non Loosening Mechanism
				Narrow UG Chain
PD	Pedal		PD-7401	410g 14.5oz (Pair) 85g 3oz (Hardware)
				34 degree Clearance
				Nickel Cr-Mo Axle
				Adjustable Cleat Grip Tension
				9/16x20TPI
				French M14x1.25
				Compound Type Needle and Cup/Cone
Brake Levers	BL		BL-7400 (Std)	216 grams 7.7oz (pair)
			BL-7401 (Aero)	254 grams 9oz (pair)
				Light Alloy High Tech Grey Anodised Finish Lever
Brake	BR		BR-7400	382 grams 13.5oz (F&R 49 Type)
				Redesigned Shoe Holder
Seat Pin	SP		SP-7400-A (Round)	224g 7.9oz 26.8mm
			SP-7400-B (Semi Oval)	244g 8.6oz 26.8mm
				Hexagon Release
				Light Alloy Anodised Finish
				25.0, 26.2, 26.4, 26.6, 26.8, 27.0, 27.2, 27.4

1988 – Shimano Dura-Ace 7402 8 Speed (Integrated 8 Speed SIS)

By the time 1988 came around, I’d been a mechanic in a shop for a little while and had seen first hand the struggle between Campagnolo and Shimano. We were selling high volumes of Shimano equipped mountain bikes and those manufacturers also did a handful of Shimano equipped road bikes. The only Campagnolo equipped bikes we were selling were custom builds, and even then it was probably one Campagnolo bike to every two or three Shimano.

Towards the end of 1988, Shimano pushed things just that little bit further by introducing their Integrated 8 speed. A new freehub, 8 speed cassette, shift levers and rear derailleur. Shimano also changed the spec of the chainset by adding additional length crank arms and Biopace rings. Dura-Ace 7402 also introduced Shimano Linear Response (SLR) brake levers and calipers. The only components to remain the same were the original 7400 front hub, front derailleur, seat pins, head set and bottom bracket. The PD-7400 and PD-7401 were also kept the same.

My own build of my 1988 SB8868 Reynolds 753R has a complete and date period correct Dura-Ace 7402/7401/7400 ensemble. The newly released 7402 group consisted of the following new and existing parts…

• RD-7402 Rear Derailleur
• FD-7400 Front Derailleur
• FH-7402 Integrated 8 Freehub (130 mm OLN)
• HB-7400 Front Hub
• SL-7402 8 Speed Shift Levers
• CS-7400-8 8 Speed UG Cassette
• FC-7402 Double Chainset
• PD-7401 Clipless Pedal
• BL-7402 Aero SLR Brake Lever
• BR-7402 SLR Brake Caliper
• HP-7400 Head Parts
• SP-7400 Seat Pin Round Type (27.4)
• BB-7400 BB Set
• CN-7400 Narrow UG Chain

The data below is taken from Shimano’s “Bicycle System Components – The Complete Line” catalogue dated August 1988.

Rear Derailleur	RD		RD-7402	Min 12T Max 26T Max Diff 26T
				205g
				Double Servo-Panta Mechanism
				Centeron Guide Pulley
				Ceramic Pulley
				Adjustable Return Spring
				Sealed Pivot Axles (O-ring)
				Sealed Link Pivots
				Double Spoke Barrier
Freehub	FH/HB		FH-7402 (Rear 8 Speed)	460g Rear w/o sprockets
			HB-7400-F	Contact Type Sealed Mechanism
				Stainless Steel Ball Bearings
				130 OLN
				Uni Balance System
				28 32 36H
				Lubrication Ports
Cassette	CS		CS-7400-8	12-19T, 12-21T, 13-24T, 13-21T, 13-26T
				255g (12-21T & Spacer)
				Champagne Gold Finish Sprockets
				Threaded Sprocket 12T-14T
				Spline Sprocket 14T-28T
Shift Levers	SL		SL-7402 FCAI (8sp Braze)	67g
				30 degree offset of lever stopper
Front Chainwheel	FC		FC-7402 (Std Double)	643g (42-52T 170mm)
			FC-7402-BP (Biopace)	Inner 39-47T (Round) 42T Inner (BP)
				Outer 48-56T (Round) 52T, 53T (BP)
				165, 167.5, 170, 172.5, 175, 177.5, 180
Brake Levers	BL		BL-7402 (Aero)	240g (pair)
				SLR (Shimano Linear Response) System
Brake	BR		BR-7402	376g (F&R 49 Type)
				SLR (Shimano Linear Response) System
				Low Profile Brake Shoe
				Spring Sleeve
				Thrust Bearing and Coated Pivot Washer
Seat Pin	SP		SP-7400-A/SP-7400-B	25.0, 26.4, 26.6, 26.8, 27.0, 27.2, 27.4 (no 26.2 listed)

Even though it looked very similar to the RD-7400 and RD-7401, the new Integrated-8 RD-7402 rear derailleur received a new updated design with a new casing/pivot, inner and outer plates and sealing mechanisms.

1990 – Shimano Dura-Ace 7403 8 Speed (STI)

Shimano were once again leading the rest with new technologies. Imagine being able to change gear without moving your hands from the brake lever hoods! That is what they brought us next with Shimano Total Integration (STI), Shimano’s combined brake and gear lever, or ‘Dual Control’. Not only did they make the process of gear changing easier, they also made the change smoother by introducing Hyperglide (HG) cassettes into the Dura-Ace line-up. Braking performance also received attention and the newly introduced BR-7403 Dual-Pivot brake calipers made an immediate impression with their stopping power. Dual Pivot calipers were also extremely easy to centre and they maintained their central position – something that always affected standard side pull calipers.

The new 8 speed STI levers received a new designation of ST-7400. The LH STI lever had a ‘trim’ facility to move the front derailleur cage slightly as the chain travelled up and down the rear cassette and was provided to stop chain rub against the cage plates. To provide the STI functionality and trim facility in the front derailleur, the cage was changed slightly and a new adjustable return spring was fitted. The new derailleur received a new model designation of FD-7403.

New to the Dura-Ace lineup was Hyperglide (HG). This type of cassette had a totally different locking system to keep the cassette on the freehub body. This meant a new Dura-Ace freehub body and new rear hub designation, FH-7403. A new set of Bar End 8 speed shifting levers were also added, SL-BS50-8.

Rear Derailleur	RD		RD-7402	Min 12T Max 26T Max Diff 26T
				209g
				6, 7 & 8 Speed SIS Compatible
				STI Compatible
Freehub	FH/HB		FH-7403-HG (Rear 8 Speed)	439g Rear (with QR)
			HB-7400-F	STI Compatible
				HG Gear Compatible
Cassette	CS		CS-7401-8 (8 Speed HG)	12-21T, 13-23T, 12-23T
				255g
				8 Speed HG
				STI Compatible
Chain	CN		CN-7401	STI Compatible
				Narrow Type HG Chain
Shift Levers	SL		SL-BS50-8	183g
				8 Speed SIS, SIS-Friction Mode Switch
				19.0 mm, 22.0 mm Bar Inner Diameter
Front Chainwheel	FC		FC-7402-SG (Std Double)	643g (42-52T 170mm)
				STI Compatible
				Shimano SG Gear
				A-53×42, A-52×42, B-53×39 Teeth Combination
Front Derailleur	FD		FD-7403-B (Band)	15T Capacity
			FD-7403-F (Braze)	93g
				STI Compatible
				Shimano SG Gear Compatible
				Sealed Link Pivots
				Rigid Chain Guide
				Adjustable Return Spring
Brake	BR		BR-7403	432g (F&R 49 Type)
				STI Compatible
				Super SLR Compatible
				Easy Adjust
				Spring Adjust Spring
Dual Control Levers	ST		ST-7400	560g
				STI Compatible
				8 Speed SIS Compatible
				Super SLR Compatible

1993 – Shimano Dura-Ace 7410 8 Speed (STI)

This is probably a good period to demonstrate how Shimano would often introduce components and tweaks to design ahead of a major new group release. Groupsets occasionally transitioned slowly over time until there was enough of a significant difference to launch them as a new standalone ensemble. The 7410 SPD and sealed bottom bracket are two examples of components that appeared before the others.

The left hand image above shows the main parts of the previous 7403 group, but it also shows the PD-7410 SPD pedal, this was before the introduction of the rest of the 7410 group (middle image). The two outer images also reference the BB-UN91 sealed unit bottom bracket in use with the FC-7402 crank, instead of the original BB-7400.

The Dura-Ace identification number of 7410, shows that this was quite a significant jump, it was still essentially an 8 speed 74xx set of components, but things were taking a big move forward. The design was changing and moving towards its eventual replacement with 7700.

The 7400 bottom bracket and 7400 head parts had received a redesign. Out went the standard cup and cone bearings and the transitional BB-UN91 BB, and in came the BB-7410 unit and cartridge bearing HP-7410 head set. The original clip and strap PD-7400 which had been superseded by the clipless PD-7401 was now joined by the PD-7410, Shimano’s Dura-Ace SPD road pedal (Shimano Pedalling Dynamics).

The standard profile crank, FC-7402 with 112 mm BB axle, was replaced in the 7410 lineup with a low profile FC-7410 crank that required the 103 mm axle in the BB-7410 unit. This new crank and BB also received a new front derailleur, FD-7410. The group was also updated with a new SP-7410 Easton Aluminium Seat Pin. Even though this is the latest in the 74xx series the fine detail specification is hard to track down. All the data I’ve been able to find at the moment is based around component weights. As far as I can tell, the existing components from the 7403 group remained unchanged (RD-7402, ST-7400, BR-7403, FH-7403, CS-7401, CN-7401 & HB-7400).

I’ll add more detail specification as and when I find some.

Front Chainwheel	FC		FC-7410	589g (39-53T 170 mm)
Bottom Bracket	BB		BB-7410	224g 103mm
PD	Pedal		PD-7410	313g (Pair)
				36 Degree Clearance
				Cro-Mo Steel Cartridge Axle
Front Derailleur	FD		FD-7410-B	97g (28.6 mm Clamp Type)
			FD-7410-F
Head Parts	HP		HP-7410	102g
				Sealed Cartridge Bearings
Seat Pin	SP		SP-7410	192g (275mm 27.2 Diameter)
				Easton Aluminium

So what happened next…

Everything changed!

Dura-Ace 7700 was introduced in 1996 and the entire series was revised and updated to 9 speed. Two years later in 1998, Shimano released their 25th Anniversary Dura-Ace group based on their 7700 components, celebrating the 25 years since the original 1973 release.

And that is where my blog post ends. Dura-Ace 7400 was no more!

Even though the original 7400 qualifies for vintage events such as L’Eroica, it has to be considered as a ‘modern’ group, it brought so many new innovations to the bike industry and pushed other manufacturers to up their own game. The popularity, durability and functionality of 7400 keeps it at the top of the wish list for lots of classic bike builders. SB8868 is my 1988 8 speed 7402 version and I’m really looking forward to getting SB6560 built as my 1984 7400 6 speed bike.