Category Archives: 3. Parts & Tech info

A very personal view of cycling products and technical reviews

A case of study: 29er inner tubes


Not long ago bike shops struggled to source specific 29er tubes (700x54mm). A widespread practise was to overinflate the classic 26″ size or 700x35c inners with the risk of sudden blow ups, decreased rolling eficiency and more punctures. Only some beefy tubes behaved well with no surprises for this purpose.

Foto 1 Nikki Gudex tubes

Tubes are within the most iconic bicycle components

Now the market is full of 29 inches tubes. For around £4-5, 6-7€ or 7-8$ you can afford good quality spares. Maxxis (Taiwan) and Schwalbe (Germany) are remarkable brands that produce tubes in many different sizes.

After damaging the original “unlabelled” tubes that came with my bike (probably made by CST, Vee or any other asian bulk manufacturer), I picked the Maxxis Welterweight (4,24€) and Schwalbe Extra Light (6,60€), both in online stores, to give them a go.

A thousand kilometers after testing the tubes with new tyres, the Maxxis tube has result in an amazing and absolute quality product. A bargain for the price (now over 5€).

Maxxis tubes are always true to the word of the company. Since the moment you open the box they meet the announced weight in the worst scenario, and sometimes a lot less.

The Welterweight is not a weight weenie product unlike the intended use of the Schwalbe Extra Light. Officially 205g. versus 140g. Note that the thickness of the butyl wall and tube dimensions will determine its final weight. The valve type, porosity and overall rubber quality have a negligible impact on it.

Foto 2

Maxxis tubes are made in Taiwan while Schwalbe units come from Indonesia

The good thing of the Maxxis is the fact that it is a real 29er inner tube. The Extra Light tube width doesn´t meet the requirements to fit securely a 2.4 tyre despite it is recommended for this size. It is clear when you put them close together that something is wrong in the Extra Light product. It looks like a 700x35c spare.

But what is even more shocking is reading the compatibility printed in the cardbox. It suits also 650b/584mm/27.5 wheels! Wouldn´t have been any wiser to make a compatible 650c/26″/559mm and 584mm tube while producing separately the specific 29er size? The discrepancy of the 29er size (622mm) with the 584mm standard is more than the 559mm measure has instead.

Foto 3

A nonsense of tyre matching specifications that even claims 700b compatibility (635mm)

The result is that the Schwalbe model is not a proper 29er tube and nor a 650b one. You have to slightly overinflate them on 2.2 Continental Mountain King tyres for example. It’s tricky to slide equally the tube inside the tyre bulging it on many ocassions unless you use an air compressor.

What’s more I got quite a few flats. None with the Maxxis. I reckon even the rolling eficiency is compromised with such a tight fitting. A hassle.

The final blow came when checking the weights. The taiwaneses are only 40 grams on average heavier than the germans, instead of the expected 65g.

Average weights

Average weights. Less than 40 grams average discrepancy between models

Cheaper, easier installation, more reliable and keeping the pressure for longer my vote is on the Welterweights. It’s great that Maxxis produces almost each single size of bicycle inner tubes. Meanwhile the design of the Extra Light tube is all messed up.

Shimano abandoned systems


Lately I’ve been gathering information about Shimano trademarks, inventions and products. I found out interesting writing down a long article to explain those technologies that did not succeed and finally faded into oblivion.

Again I have to thank Sheldon Brown for his articles. I did some copy&paste to explain those parts I never dealed with in the flesh. I also checked some internet bike boards and did the same when it was strictly necessary :mrgreen:.

You will be amazed how some of the solutions adopted work and their gadgety and funny design.

They all share something: they vanished off the face of the earth for uncertain reasons and no longer available, they are all Shimano genuine trademarks with no plagiarism, there is a lot of controversy if they were any good, and they will make you think “why the fuck I’ve never heard about the majority of them” 😀 .

10 . Dyna Drive ®

In the early 80’s, Shimano introduced a special crank/pedal set, which used much larger diameter threading where the pedal screwed into the crank. This allowed them to build the bearing into the inside of the pedal thread, eliminating the need for a pedal axle. The purpose of this was to improve the ergonomics of the pedal by placing the bottom of the foot below the pedal axis.

A good idea biomechanically, but never caught on. In practice, the pedal bearings turned out to be underengineered for the loads they had to deal with.

Designed to lower the rider’s center of gravity and improve aerodynamic too. You can get spindle adapters to run standard 9/16″ pedal spindles

9. Front Freewheel System ®

The Shimano Front Freewheel System (FFS) was a proprietary drivetrain seen for the first time in 1977 that placed a freewheel between the pedal cranks and the front chainrings.

The “freewheeling” mechanism is built into the crankset bottom bracket, but for safety reasons, the rear cogs are not just fixed to the wheel. The rear freewheel had higher friction than the front so that the spinning of the wheel will drive the freewheel and chain when coasting enabling the rider to shift gears with no pedal strokes. In fact, walking the bicycle drove the rear wheel and chain, allowing shifting if you had left the bicycle in too high a gear. You simply had to push the bicycle forward and move the lever to select the desired gear.

If an object, such as a pants cuff, gets caught in the chain, the rear freewheel engages. This overrides the FF mechanism and the chain stops moving.

The resulting system proved good reliability. The major problem was that local bike shop salespeople did not take the time to learn the system and what it could do for novice cyclists. Besides it was heavier and more complex than a standard freewheel, we can conclude that offered features that no one really needed and, in any event, did not penetrate the market noticeably. Sheldon Brown called FFS “a solution in search of a problem”.

sdf

FFS marketing followed Shimano’s path of beginning with lower-cost implementations of the system using low tech and usually heavier materials

8. Interactive Glide ®

The IG abbreviation for Shimano Interactive Glide gear system is an extension of the Hyperglide concept, in which both sides of the bicycle gear sprockets are physically contoured and ramped on the face of a cog to improve upshifting.

Interactive Glide sprockets are slightly thicker than Hyperglide ones in order to mantain the full thickness of the teeth, and as a result, HG chains may hang up if used on an IG cassette. IG chains will work on HG cogs though. Since the sprockets are thicker, the spacers must be thinner to have the correct spacing on 7 and 8 speed systems. However, IG chains are narrower, 7.1mm vs 7.4mm for the HG versions.

Shimano said that you shouldn’t mix IG and non-IG sprockets, but if you use one IG spacer per IG sprocket, you should be all right.

IG was released in 1995 in the mid-range, between STX-RC and Alivio drivetrain parts. Apart from some XT chainwheels, it never reached the more refined gruppos. It disappeared in short time because of the higher prices and, given the good shifting quality of the HG chainsets, goodness knows what the new features were trying to improve upon.

HG chain has bowed-out outer link plates (bottom). IG chain (top) has nicks out opposing corners of each outer plate to facilitate outward shifting.

HG chain has bowed-out outer link plates (bottom). IG chain (top) has nicks out opposing corners of each outer plate to facilitate outward shifting

7. Intego ®

Shimano has a long tradition (and a worthy chunk of its cycling business) around internal gear hubs. But failed caming out with the Intego hub as it had already other well stablished models and the fierce competence of the better SRAM Dual Drive, which was all poshed up from the previous Sachs 3×7.

The Shimano outcome was not a bad idea. As others competitors did, the japaneses pretended to revitalise the city bike market with a hybrid hub that could do the transition between conventional derailleurs towards geared hubs, providing the same wide gear ratio.

The design mixes a 3 speed internal gear hub with a freehub so that it eliminates the hassle of a front mech (the one that works worse) whenever an 8-9 or even 10 speed cassette is installed on it.

Shimano Intego IF-C530 with roller brake option

Shimano Intego IF-C530 with roller brake option

6. Positron ®

The PPS System was Shimano’s first attempt at indexed shifting. The “clicks” were built into the derailleur, not the lever. Unlike conventional drivetrains, the system didn’t have a return spring; some models used a double cable to pull the mech back and forth, other models used a single, semi-rigid push-pull cable.

Positron was a valuable learning experience for Shimano. In 1982, the theory was that experienced cyclists already knew how to shift, but beginners could benefit from a system that didn’t require fine-tuning of the shift lever position. For this reason, Positron was offered on entry-level bikes. This marketing theory turned out to be unworkable. The parts had to be made very cheaply to meet the price points required. This caused a less-than-impressive performance. In addition, the fact that Positron was only supplied on bottom-end bikes caused it to acquire a poor connontation, as something to be outgrown, and not to be considered by “serious cyclists”.

Shimano went back to the drawing board, and the next time they tried indexed shifting, in 1984, they started at the top of the line, with Dura-Ace S.I.S. The result was that by 1986 it had become almost impossible to sell a bike that didn’t have indexed shifting.

Many Positron-equipped bikes also featured the Front Freewheel System®, but this was not a specific linkage. Either of these systems could and did function without the other

5. Airlines ®

Truth been said: I don´t know much about downhill. But I still remember the day, when a forum member registered on an internet board awoke my interest for a while in some information regarding a supernatural old project of creating an air-powered derailleur shifting system that Shimano upfronted between 1996 and 1999.

At first sight it seems a seedy configuration -quite the contrary- it was developed based on input provided by professional racers riding prototypes in competitions.

The advantage of Airlines pneumatic shifting action is that allows the off-road to shift gears instantaneously with a minimum effort and lag.

You can find plenty of information and pictures in the original publicity leaflet: specs, the team in charge of the developement, a very limited production, hand assembled parts in a special Shimano facility…

The development has all the ingredients of those top-notch creations that never pay off but show the power of a company. An abandoned idea because of the costs of production and constant refills of compressed air.

Shimano Airlines

The tank and air regulator are the most distinctive components in the system that also includes shifters and a special 7 sprocket cassette with 9 speed spacing

4. Silent Clutch ®

The Silent Clutch in Shimano’s terminology is a type of freewheel ratchet mechanism which uses cams and rollers instead of pawls. The patent goes back to 1996.

In addition to eliminating the noisy “tick-tick-tick” of a pawl-type freewheel, a roller clutch has less slop when drive force is applied to it. Drive begins as soon as forward motion of the pedals starts, unlike a pawl-type freewheel which only drives once it has rotated far enough to let the pawls engage the notches of the ratchet ring.

The technology has been used notably in the Shimano Nexus and Alfine series but discarded in the Freehub types.

These freewheels were reported not to stand the test of time and also being heavy.

These freewheels were reported not to stand the test of time and also being heavy

3. Rapid Rise ®

In 1998, a new rear mech known as Low-Normal in Shimano’s slang came to life. Both beloved and hated by the mountain bike community, Rapid Rise were discontinued a decade after with the advent of the Shadow type that does not play well together with inverted parallelograms.

The idea behind is that it’s easier to rapidly shift to an easier gear when you suddenly face an uphill struggle.

Rapid Rise resting position works the opposite way as the spring retracted is in the lowest, easiest (biggest cog) gear. Hence ‘Low-Normal’. When you release all the tension, the chain goes to the easiest/largest cog.

You have to use your thumb lever to pull the spring and shift to a higher (more difficult, smaller cog) gear, and your forefinger to release the tension and let it jump to a lower gear (though this lever flick both ways these days, so you can use thumb as well).

After few years of scepticism, Rapid Rise mechs underwent a revival when they were frequently matched with Dual Control levers until they finally took the same bus out of Shimano town.

I suspect that these mechs just had too small sales volume to keep going with them as they seemed to rub a lot of people the wrong way.

rapid rise 2

XTR RD M951 Rapid Rise weirdness was released in 1998 when MTB 8 speed generation was still alive, but discarded a year after for the model M953 (9 spd) that did not include that distinctive pulley to avoid sharp radii and excess of housings and thus reducing friction. Shimano stated an improve of 10% in smoothness

2. Dual Control ®

This is the case of one of the most notorious fails in Shimano’s history.

Dual Control (DC) levers were introduced in 2003 to mountain bikes, letting you switch gears with the brake handle thanks to a shifter that was integrated into the brake.

The development was controversial as the use of DC integrated shifting for hydraulic disc brakes required using also Shimano hydraulic brakes, locking competitors out of the premium end of the market. However, with their 2007 XTR second generation DC product line, Shimano moved back to make separate braking and shifting components fully available in addition to the integrated “Dual Control” components. A move to satisfy riders that wished to use Shimano shifting with other brands of disc brakes.

These components found their own niche, like Rapid Rise mechs did, but then again, bummer acceptance rate ended up with Shimano ditching a functional design by the time the generation of 10 speed MTB systems were unveiled.

The main advantage of DC is that a rider can go down the hill into rock/root and shift at the same time of braking.

d

2nd generation V-brake and Dual Control combo unit. Top rarity

1. Biopace ®

Biopace is Shimano’s tradename for a type of ovoid chainring produced from 1983 to 1993.

Non-round chainwheels are designed to provide varying mechanical advantage, changing the gear ratio at different angles of crank rotation with the intention to be more ergonomic by helping to overcome the “dead pedal stroke zone” where the crank arms are vertical and riders have little mechanical advantage.

Biopace chainrings do almost exactly the opposite to the intention of most oval style chainrings, where at top and bottom dead centre (BDC) the effective diameter of the chainring is small, having Biopace the reduced chainring diameter coinciding with the cranks being horizontal.

It is now easier for the rider to turn through BDC allowing the legs to carry a lot of momentum through the power stroke.

By having the chainring at its peak effective diameter with the cranks leveled, that is, where the rider has maximum leverage over the crank during the power stroke, better use of the speed of the legs can be made to increase power output.

The reason this is beneficial is that it tends to smooth the pedalling action but encouraging riders at the same time, to push bigger gears and risk knee damage due to higher knee joint loadings.

In those days, a minority of cyclists found their benefits worthwhile (including Sheldon Brown), but most of them occasional cyclists. Rare usage in pro-bikes and the difficult bio-dynamics involved did not prove the advantages of non-circular versus circular forcing shimano to discontinue the Biopace era.

It is still very controversial, but all we guess when comparing Biopace to most modern oval chainrings is that Shimano went with the wrong concept, assuming non-circular chainrings may improve pedal dynamics by reducing the effect of the “dead spot” in the pedaling cycle rather than thinking on elliptical rings to be more efficient through matching the torque output capability of humans to the torque input requirement of the pedaling cycle.

Another gem hard to see. Outer Biopace chainring for triple 110mm touring cranksets (1986-1988)

Another gem hard to see. Outer Biopace chainring for triple 110mm BCD touring cranksets (1986-1988)

Brompton inner tubes


As we’ve seen in previous entries nothing in the Brompton universe is straightforward. Inner tubes compatibility are ample proof of this.

If you eventually need to replace them, bear in mind that a regular 16″ children bike tube will not fit. This is the one you are likely to find in a rush in a bike shop and for your surprise too wide. You’ll notice is very tricky when sliding it inside the tyre. These inners will cover ranges between 1.75 to 2.125 inches (45-50mm).

On the other hand, Bromptons are equipped with up to 1.37″ (1 3/8″, 35mm) inches width tyres. Schwalbe makes good quality spares and are the ones I recommend.

Compatible inner tubes suit from 28 to 37 mm width tyres

Compatible inner tubes must suit 28 to 37 mm width tyres

Most of the Brompton compatible tubes fit tyres from 340 to 355 mm bead seat and widths from 28 to 37 mm approximately.

16 inches inner tubes are very light :mrgreen:

16″ inner tubes are small and as a result very light :mrgreen:

Best Shimano innovations (2/2)


Let’s go with the second part of this massive Shimano’s history review. I am sure this time some of the trademarks will catch you off guard.

20. Shimano Custom-Fit®. Winter sport disciplines have been using heat-moldable insoles in boots for over 20 years. In 2007, Shimano was the first company to offer this technology in several models. As with ski boots, the idea here is to provide added comfort inside the stiff footwear eliminating those spaces and irregular contacts keeping the foot in place better, which also improves performance. Check out this interesting video:

The insole is first heated up in a special oven and then molded it to the shape of the foot by another vacuum device.

The insole is first heated up in a special oven and then molded it to the shape of the foot by another vacuum device

19. Servo-Wave®. Ideally on MTB rim brakes the pads should be set for generous rim clearance. This affects the brake lever actuation disminishing initial cable pull mechanical advantage. On the other hand, a brake system with too little initial mechanical advantage will push the shoes against the rim quickly, in response to a small amount of hand lever movement, but won’t push them hard enough at the end. Shimano introduced in the mid 90’s Servo-Wave levers with variable mechanical advantage that increases as the lever is pulled. Brake levers will pull more brake cable at the start of the lever stroke than at the end. Servo-Wave therefore gave improved separation between the brake shoes and the rim, delivering the same braking power as systems that have a constant ratio between lever movement and cable pull. Servo-Wave has also appeared for the first time in 2008 on a hydraulic Shimano XT lever.

Servo-Wave lever with three adjustment positions

Servo-Wave lever with three adjustment positions

18. Dual-pull front derailleurs. A modified design in the lever that routes the cable coming from the shifter towards the pinch bolt was introduced successively in all Shimano front derailleurs since 2003. A simple feature that allows any frame to work with any derailleur regardless of its routing. Dual-pull and shim adapters for different tubes sizes reduced the alarming growing variety of mechs in Shimano’s catalog, in particular those in the low range groupsets.

Different cable routings for down and top swing front derailleurs

Different cable routings for down and top swing dual-pull front derailleurs

17. Superglide®. Hyperglide’s brother Superglide came into existence a year later, in 1990. Superglide chainwheels were sold in sets designed to work together to facilitate front shifting. The first incarnation consists of a specially low tooth profile segments (twice repeated in opposite places of the chainring) inspired in the Uniglide system, and ramps design that only let the chain drop at the two points of lower pedal stroke pressure.

Late Shimano 80's adverts looked like this

Late Shimano 80’s adverts looked like this

16. Shadow-Plus®. The incomplete Shadow rear derailleur type was launched in 2008 for both XTR and Deore XT 25th anniversary gruppos as an option. For the trained eye, Shimano’s Shadow similarities with Sram mechanisms somehow confirmed that Sram was on the right direction for years ahead. Shadow came on stage in order to diminish cage movements for those riders that are most at home on technical trails. But left a lot of them unhappy failing at shifting smoothness and cages still bouncing. Unexpectedly, Shimano added a “plus” for the 2012 version. New models use a clutch mechanism to partially lock out the lower cage by increasing the friction. This reduces chainslap, making the chain less likely to come off on rough terrain and improves shifting consistency.

For ease of wheel disassembly the clutch can be enabled or disabled with the upper golden lever

For ease of wheel disassembly the clutch can be enabled or disabled with the upper golden lever

15. Uniglide®. Uniglide was incorporated to Shimano’s slang with the invention of the freehub. It specifies a new way to attach spockets onto the hub in a symmetrical 9 splines pattern along its body circumference. At the same time, Uniglide featured new characteristics on chains and sprockets towards the modern gear performance we now enjoy. These cassette sprockets used teeth that have been cut shorter in height than most of the others and a twisted tooth design. Chains were made of bent outer plates to achieve a wider opening every other link. Different spacer´s width between sprockets permits to configure a system from 5 to 8 speed. Sprockets smaller than 14 teeth used a built-in spacer. 15 teeth and bigger were reversible. Unlike its successor (Hyperglide cassettes), the smallest sprocket is at the same time a self locking ring as it goes threaded holding everything together.

First Hyperglide body hub ends had both internal and external threads to work also with older Uniglide clusters

First Hyperglide body hub ends had both internal and external threads to work also with older Uniglide clusters

14. Mega 7®. Due to the constraints of room to provide access to the bearing cone and fit a freewheel removal tool, it was impossible for years to produce a freewheel with anything smaller than a 13 tooth sprocket. It was quite startling when in 2001 Shimano re-engineered the freewheel introducing the Mega 7, suitable for 11-12 tooth sprockets. For example, a bizarre 11-13-15-18-21-24-34 (known as MegaRange) setup, provided a reasonable step between cogs for crusing with the exception of the innermost 10 tooth jump for the steepest ascents. After winning the 80’s war against the freewheel, the well established Shimano Freehub wasn´t afraid anymore of competitors for the higher end bikes segment, but in the meantime, the company had lost attention in the lowest. Note that MegaRange does not necessarily implies Mega 7. It has to be present the slim black lockring at the end and one 11 or 12 tooth sprocket! The unknown gem of Mega 7 is also known as Type C freewheels, like the Hyplerglide-C cassettes that allow up to 11 tooth sprockets. The design has been copied by other companies.

Note that MegaRange does not necessarily implies Mega 7. It has to be present the slim black lockring at the end

Unfortunately Mega 7 has been discontinued few years ago due to high cost of production. The picture above is just a MegaRange freewheel.

13. UN Bottom brackets. In 1992, Shimano unveiled the sealed bearing cartridge bottom bracket for indistinct use with their road and mountain groups. A new saga series of “UN” bottom brackets hit the roads and trials with great success despite mechanic’s skepticism and the hassle of a new tool in the workshop, the famous TL-UN72. The non-serviceable unit demonstrated to last as long as the old units with no re-grease bearing service requirements.

One of the products that Shimano could not patent

One of the products that Shimano could not patent

12. Hollowtech®. A manufacturing technique that has sourced lighter and stiffer cranks all of a sudden in 1996. There are more patents than you may think for producing hollow cranks. But then again, Shimano was the first one to introduce it with no recall issues in almost 20 years of existence. Don´t confuse Hollowtech with Hollowtech II and their crazy hollow axles and outboard bearings.

The inside of a primitive Hollowtech LX crank

The inside of a primitive Hollowtech LX crank

11. Ice Tech®. In 2011 a full revamped XTR brakeset (new master cylinder, pistons…) benefited also from an ingenious 3 layer disc rotor with aluminium core design and brake pads with heatsinks incorporated. Focused on heat dissipation, IceTech introduction has resulted in virtually zero brake fading, reduction of noise and increased pads life expectancy. You might think I am a little bit cheeky positioning such a new technology on here… time will prove.

My ex-headmechanic Seun gave me these cool fridge magnets imitating the new brake pad fins desing

Best Shimano innovations (1/2)


Japanese companies and the Japaneses are incredible inventors.

They have become some of the most innovative industrial bases in existence, being capable at the same time to interpret a design, improve it and then make money out of it quickly.

This might be the case of Shimano, but saying that they only refine but not conceive is really to disregard the truth.

shimano_logo_nblusm_04_p

This article is somehow a tribute to my favourite company and also Sheldon Brown contributions. Indeed, it took me some time to review his site to sharpen this entry while I was blurting out these sick lines.

Enjoy.

10. Rapidfire Plus®. Rapidfire is one of the coolest inventions in the mountain bike history displacing top mount shifters on flat bar bikes in 1990. Originally, the rider’s thumb triggered the lower lever for upshifting and the smaller upper one for downshifting. Both in the same direction and using just the thumbs. A year after the more ergonomic radipfire + required the index finger to operate the downshifting in the oposite direction. 2-way release Shimano´s trademark is a minor improvement incorporated to operate the downshifting using again the thumb or index finger according to the rider’s preferences. They can be seen integrated with brake levers (EZ-Fire series) and with or without gear display.

XTR SL-M970 Rapidfire Plus shifters incarnation with rareYumeya parts. Its multi-release allows shifting two gears at once in both directions.

XTR SL-M970 Rapidfire Plus shifters incarnation with rare Yumeya parts. Its multi-release allows shifting two gears at once in both directions

9. V-brake®. Recognized to be the best mechanical rim brake system for applications that need tyre clearance. It’s a direct-pull design since there is no intervening mechanism between the cable and the arms and thus very convenient for full suspension bikes where extra fittings on the frame and fork would be required to install cantilevers. It’s a linear pull brake because arm’s movement is the same that cable moves with regard to its housing. First v-brake units date back to 1996. They featured a sloppy linkage that allowed the pads to move in and out in a horizontal line to the rim.

Rebuild kits were soon unveiled

Rebuild kits were soon unveiled

8. Super SLR® (Shimano Linear Response). This is Shimano’s name for dual-pivot brake calipers. Shimano relaunched an old design present in few touring bikes, the dual-pivot & side-pull calipers concept. Still used on most modern road bikes, dual-pivots combine one arm pivots at the centre, like a side-pull, and the other pivots at the side like a centre-pull. The cable attaches the brake like a side pull does. 105 was the debut groupset for these brakes. Some pros decided to take their brakes out of fully Dura-Ace equipped bikes during the year 1990 to fit 105’s.

BR-1055 dual pivot superseded top quality side pull-single pivot BR-7402

105 BR-1055 dual-pivot superseded top quality side-pull Dura-Ace BR-7402

7. Hyperglide®. This is the given name for Shimano drivetrain parts to denote those having common characteristics. The term involves chainsets, cassette hubs and rear derailleurs that came out for the first time in 1989. Sprockets on a Hyperglide cassette or freewheel are created specifically to work with their neighbors. Rather than having teeth just cut down in height (Uniglide), a system of ramps and special-shaped group of teeth operate in concert together to facilitate shifting. As a consequence, cassettes are sold as a block with an option of a spider attaching the sprockets. Teeth profile, along with laterally floating jockey wheels, have improved rear shifting more than any change in derailleur’s design in the last 20 years (Sheldon Brown).

HG logo is hardly seen anymore in packaging to make room and help selling trivial innovations like Dyna-Sys

HG logo is hardly seen anymore in packaging to make room and help selling trivial innovations like Dyna-Sys

6. Compressionless index housings. In the late 80’s new cables were sourced to work with S.I.S. This time with no registered trademarks as everything came up as a constellation of new products under the S.I.S. logo. The advent of index shifting combined with handlebar mounted shifters developed that conventional housing was a source of imprecise shifting. This is because the effective length of the housing changes as it is bent. This is not a problem with brakes but the small variation in length was too much for reliable index shifting. However, Shimano introduced S.I.S. compatible housing, now widely copied by other manufacturers. This type of housing does not consist of a single spiral-wound wire, but instead, it has multi-strand wires running pretty much straight along parallel between the inner lining and outer plastic casing.

Shimano SIS SP41 now come in flavours

Shimano SIS SP41 now come in flavours

5. SPD®. Shimano Pedaling Dynamics, better known as SPD system is a design of clipless bicycle pedals. While not the first, the innovation was its small cleat recessed into the sole of the shoe. The shoe could be also used for walking in the trails whereas previous systems (other than the Cyclebinding system) had a large protruding cleat. SPD had a huge impact in the mountain bike history becoming the most affordable and wise change on a bike towards performance in 1990.

535-Shimano_PDM324

SPD binding on one side provides security and pedaling efficiency. Standard cage on the other side makes it suitable for flats

4. S.T.I.® This acronym is used to refer to combined brake/shift control levers, particularly those designed for drop handlebars. Brakes and gear shifters in the same unit allow shifting gears without having to remove the hands from the bar, unlike previous shifters installed in the downtube. It completely changed road racing cycling competitions. A more ergonomic brake hood to rest the hand, a faster gear action and boosted security in descents and sprinting helped Shimano to take the lead in the cycling manufacturing in the early 90’s.

In 1990 Shimano's Dura-Ace pushed Campagnolo into the background for the first time in 50 years of road racing tradition

In 1990 Shimano’s Dura-Ace STI pushed Campagnolo into the background for the first time in 50 years of road racing tradition. The picture above belongs to the whole groupset offered in 1992

3. Di2®. In 2008, a year before it was available for the general market, three road professional teams tested the first successful electronic gear system. While traditional mechanical levers pull and release Bowden cables and spring-loaded derailleurs, Di2 is controlled by switches that send signals through a wiring harness to a battery pack. The rechargeable and long lasting battery unit supplies power to the derailleur motors, which move the derailleurs via worm gears.

etube

E-tube project will be Shimano´s flagship in the next years providing diagnosis, updating and bespoke system configuration

2. Shimano Index Shifting (SIS®). Index shifting means that the shifter unit has click stops that provide discrete positions corresponding to different gears. Up through the mid 80’s, derailleur equipped bicycles used “friction” shifting. The shifter was a simple lever held in place by friction, and the rider was expected to learn how far he had to move it to switch from gears. If the lever was moved the wrong amount, the rear mech might shift the chain too far, or override between gears so the chain would run balky and noisy.

10 spd XT mech

To accommodate 10 speeds, MTB mechs reduced their actuation ratio to 1:21:1 for the first time in Shimano’s MTB universe

 1. Freehub®. With no doubt one of the top 10 achievements in the history of bicycles. The oldest and most trascendental invention listed in this article. At the beginning of the 80’s Shimano segregated the freewheel mechanism from the sprockets so that all type of bearings would be built inside the hub body. Due to the outboard location of the right bearing, the axle is supported closer to the ends. As a result, bent or broken axles are rarely a problem. At the same time, a new concept came into existence: the cassette. This is why freehubs are also called cassette hubs. Sprockets are now easily removable and cheaper than freewheels.

The Capreo freehub body has a special design to fit smaller 9 and 10 tooth sprockets in small wheeled bicycles

2003 Capreo freehub has a special design to fit 9-10 tooth sprockets for small wheeled bicycles

Rohloff axle plate types & Speedbone vs. Monkeybone in the OEM2 configuration


The axle plate is the Rohloff solution to tackle the inherent phenomenon of axle rotation and twisting in all internal gear hubs (IGH).

Historically this rear wheel issue has been easily solved in threaded axle hubs by using non-turn washers at the axle nuts or alternatively installing an ugly long brass arm clamped to the chainstay.

But since in 1998 Rohloff became the first high-end IGH offering a quick release version (and the unique until NuVinci added a QR option last year) a new design needed to be implemented instead of manufacturing a solid thru-axle with two flat sections where secure the tab washers.

Shimano anti-rotation washers to fit different dropout angles

The quick release (QR) is one of those features that are a MUST on a bike as it offers ease of wheel disassembly. Aside the low entry specs market, on mountain bikes the percentage is close to 99% except those riding single speed hubs or heavy load duties (tandems and so on).

The Rohloff was intended since the beginning for the top notch MTB/flatbar hybrid ghetto. Heavy duty all terrain bikes to sum up. That’s the reason it only came out and remains with a 135mm axle width and only flatbar shifter installation possible.

The axle plate in the Rohloff speech is the invention that will engage the hub securely preventing the axle from twisting whilst the rider applies force on the pedals, and also turning when shifting providing crispy gears. In physics this force is refered to as torque and must be secured somehow to a stationary point.

The axle plate comes in all RH units, and is part of a modular system that makes any frame with 135mm spacing, and any brake system out there, compatible with its assembly. There are three plates available.

Axle plates

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Picture taken from the Rohloff Owner’s Manual

They all have a hollow peg where the skewer passes through (remember this it’s not enough by itself to secure the hub) and an appendix or slot in its outer diameter to seat it properly to the frame. The difference between the three options is the fastening point to the frame.

Most of the times in a certain bike setup more than one solution is elegible. It will depend on the user/framebuilder preferences. As a consequence, there are many combinations possible because the axle plate choice should be pondered over with the core issue of how are we going to remove the chain slack in bespoke configurations growing the alternatives.

Let’s see some in the flesh:

  1. Bikes with rim brakes installed will have to use the standard axle plate with a long torque arm attached to the chainstays.
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No disc brake and no RH dropout design means long torque arm

If the frame has an unused IS disc brake mount, the long torque arm can be removed and OEM2 mounting is doable by using the lower support hole.

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Standard 135mm ATB frame with disc and rim brake compatibility

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OEM2 axle plate view using the torque support bolt method to remove the long arm

Some users riding touring bikes with no disc brake mount or frames with special needs, managed to remove the long arm screwing torque support bolts on the mudguard/carrier fittings or close locations.

An odd place to attach the axle plate on an elevated chainstay model

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Classic homemade upgrade to avoid the hassle of the chunky torque arm

From now on OEM and OEM2 plates will cover the specific issue when installing the bike on a disc setup.

  1. For standard MTB/ATB disc brake frames exists the OEM2 mounting. This is the one to consider when upgrading a bike or for simplicity reasons. I’ve got it in my bike as it came originally with standard vertical dropouts and a conventional drivetrain.

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OEM2 axle plate with Speedbone

Now it is time to introduce the Speedbone. In the previous picture you can see the plate engages the shiny pin of a bigger arm called Speedbone that goes screwed to the disc brake adaptor from the other side of the frame mount.

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The Speedbone is placed in the ISO brake mount and weights 72 grams

The Speedbone has been superseded since the Monkeybone allows to anchor the axle plate directly to the disc brake mount adaptor with no downsides. Very clever!

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The body of a conventional brake adaptor has been machined to adopt the OEM2 axle plate

In any case the Speedbone is still necessary if you’ve got an IS direct mount brake caliper.

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My previous setup with a Magura Marta SL IS caliper

The Monkeybone is a witty solution but not suitable for frames ready to go with postmount brake calipers though. Its groundbreaking appearance (sourced by an independient company) forced Rohloff to include it within the official accessories considering its importance. We will see shortly why.

  1. In an attempt to simplify the RH configuration the company specified since the beginning what they call frames with RH ready OEM dropouts. This dropout uses the OEM axle plate and is easy to implement when you create a bike from scratch avoiding the hassle of the Speedbone and also the long arm present on bikes with standard brakes in order to secure the torque. Framebuilders could take advantage of an axle plate that comes this time with a notch resting in the lower position unlike the standard and OEM2 plates.

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OEM axle plate only for Rohloff dropouts. 3/32″ chain and no chain tensioner observed means the frame has an eccentric bottom bracket

This axle plate is the favourite choice in custom bike builds where no conversion is needed (with or without removable dropouts). Since you can decide the features of the frame you want to ride and hence the dropout style, you can combine a RH OEM dropout with a sliding system to take up the slack in the chain saving even more weight.

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OEM implementation with sliding removable dropouts on top

On disc brakes where an IS/PM adaptor is necessary (the most common configuration, 95% of users?) the alternative of the Monkeybone has gained atenttion. With any type of rotor size compatibility in option and considering it integrates the look and functionality of the Rohloff OEM dropout design (even lighter) there is no need for framebuilders and users to stick to a pure RH frame just in case they want to move back to standard transmissions and also reducing frame costs. This is something to bear in mind as I said before with the method desired to provide chain tension.

All in all, 90% of bikes over 1000$-€-£ and suitable for a Rohloff have disc brakes. That’s the importance of the Monkeybone. Nearly every single mountain/hybrid bike frame will be likely and preferable to be used with the OEM2 axle plate relegating the OEM axle plate, and thus the specific design dropout, to a 10%-15% of community wishing custom builds with rim brakes and/or sliding dropouts combinations.

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Ridiculously deprecated Gustav M Speedbone that only saves some grams as improvement

Finally, I’d like to point out that all the axle plates come with 12 holes drilled equally around the circumference. This hole pattern allow adjustment of the external gear mechanism in steps of 30º so that all type of frames can receive an optimum cable routing from the rear wheel.

Shimano Center-Lock vs. 6 bolts disc hubs & rotors


How quick time goes! It’s ten years already since Shimano released its own mounting system for disc rotors (XTR 960 groupset) … and still not popular in our bikes! Why?

Centerlock is a Shimano propietary method of attaching brake rotors to a wheel hub. The disc rotor offset is the same as international standard so that a Shimano Center-Lock rotor and hub are compatible with any brake caliper system around.

First Shimano Center-Lock disc rotor: XTR 960 SM-RT96

First Shimano Center-Lock disc rotor: XTR 960 SM-RT96

Legend has it that Shimano came out with Center-Lock after facing losts of warranty issues on their hubs in just a couple of years. Just imagine the consequences of stripping the threads or round a head bolt. Nothing a bike mechanic has not ever dealed with. I think it was an idea that simply came up considering manufacturing costs process.

Cyclists usually complain about how often companies renew their catalogues and technologies. But in this ocassion I’d like to stand up for Shimano Center-Lock interfaces considering all the advantages they brought up and how fast Shimano reacted to develope a new standard.

It seems we are undergoing a revival breaking the deadlock. That’s why I would like to sum up all the pros and cons of having them installed. With only two downsides the choice it is only a matter of money 🙂

  • Ease of assembly and removal saving a lot of time and making life easier to those riders that often travel and disassembly their rotors not to suffer any damage in transport.
  • Slightly lighter hub. Even though the lightest rotors in the market are not Center-Locks.
  • You can still use an adapter to convert to a 6 disc bolt pattern.
  • As for as performance and reliability none of the two designs are better, but Center-Lock still prevents stubborn bolts or ruined threads.
  • The diameter of the hub flange is smaller in Center-Locks. As a wheelbuilder you will find a lot easier with certain hubs to have less spoke length discrepancy between left and right side, specially in front disc hubs where one of the sides has no dish, and as a result, a more similar tension in both spoke sides. Remember that spokes are likely to come loose with low tension, and not dished side of them will be tensioned accordingly less. If a 6 bolts hub has been built with both oversize flanges just to minimise this effect, it will be for sure much heavier. For example XT 756 vs. XT 760 front disc hubs. I’ve come across with 8-10 mm shorter spokes in 6 bolt wheels, even though front wheels carry less stress and are much more reliable by themselves so that spoke tension is not an issue. About the rear ones there is no difference at all.
  • You need a cassete removal tool instead of a more common T25.
  • Larger range and availability of 6 bolts rotors.