Monthly Archives: May 2013

The mysterious rubber block

I’m surprised that not many users know what is the small piece shown below for.

Well, if you’ve got big hands or you’re not a roaddie you might have never missed them.

On the subject of Shimano’s STIs they will bring closer the lever making shifting and braking more comfortable. Consider that short riders and girls mainly, have difficulties to reach the lever causing long term fatigue.

With this rubber shim inserted on top of the shifter unit the angle will be modified some degrees. Depending on its thickness you can setup the reach of the lever 4º or 8º degrees less with the original Shimano spares.

Unfortunately, they are not universal and will vary on each Shimano shifter generation.

While all ranges use rubber inserts, top notch Dura-Ace 7900 levers can be tuned with a concealed screw hidden behind the plastic decorative cover. Remove it by unscrewing the small retaining screw, then gently pry back as pictured the cover from the top. This will expose the brake cable anchor and adjuster. Turn the nylon adjuster clockwise until the desired lever position is reached.


As for the DA 9000, just pull back the shifter hood making visible the flathead screw that will allow lever reach adjustment.



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.


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.


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.


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.


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

Nitrogen/helium filled tyres for bicycles?

For safety and service reasons nitrogen is used in the aircraft and car racing industries for filling tyres as well as a compression/expansion gas for hydraulic systems.

Will we get any benefit from pumping our tyres with a different type of gas rather than air?

Absolutely not!. There will be no performance improvements and no negligible maintenance difference at all.

Indeed, it’s only practical to inflate our tyres with just few gases apart from common air. Let’s see why.

Do not raise your hope so with helium stuff

Do not raise your hopes so high with helium

Hydrogen and helium are the two smallest and lightest atoms. On the other hand the smallest diatomic molecule that can be found in nature is hydrogen gas (H2 ). Other diatomic molecules are O2 (oxygen), NO (nitrogen oxide) and CO (carbon monoxide). Air contains 78% of N2 , 21% of O2, 1% of argon and little amount of other gases.

In this scenario hydrogen and helium stand out as potential candidates due to their light nature, specially hydrogen.

The reality is that in the case of hydrogen it will leak out from tyres much faster than air. Not because its reduced molecular size. Hydrogen permeability with butyl compounds is all about. Hydrogen diffuses through the inner tube wall faster than other more rubber compatable gases. It’s a fact that helium or hydrogen dissolution inside the rubber matrix will end up in continuous top-ups, if not during our rides reducing a lot the interval service.

For example, CO2 contained in re-fill bottles, despite it’s higher molecular weight and size, has proved conclusively to leak out faster than regular air due to a higher solubility in butyl rubber which allows it to diffuse through the inner tube wall faster than smaller gas molecules.

Hydrogen and helium are then discarded within the options of inflating tyres for obviuos reasons. We will only refer to them again to talk about weight savings.

But will the nitrogen alternative be suitable?

Yes it, is. But it does not provide any advantage inside bicyle tyres.

Nitrogen gas is present in aeroplanes and racing tyres. It is used in such situations because it’s drier than air. Even though air with free moisture contain is enough in certain applications.

Secondly, nitrogen is less chemically social. Although nitrogen is not formally an inert gas, it is however considered as such as it does not readily react with many elements whereas oxygen contained in air reacts violently.

Let’s evaluate several tyre parameters in extreme conditions to determinate if there is any gain of utilising nitrogen in bike tyres.

Pressure changes with temperature.

The volume of regular air will change with heat and thus pressure. Air contains water in vapor state (in both liquid and gas forms). While the temperature rises, moisture turns to gas vapor which increases the volume tremendously at certain point. And this variation is on top of the normal rate of dilatation of gases. An undesirable phenomenon where pressure stability is required.

For car racing the main problem is to keep moisture out of the inside of the tyre so that pressure is more consistent. Most of the wheel performance and safety issues in motorsports are solved by using dried-air and therefore no moisture is present. The Formula One competition has been reported to use air in compressors that only have water extractors.

Don´t panic!. The fire was caused by a broken fuel line

Where tyre friction is critical nitrogen is preferred. Nitrogen is popular in Nascar racing for avoiding tyre explosions due to moisture overboiling and oxygen reacting with high flammable rubber compounds. It is appealing as well where large volume of air is inside the tyre, and that means a lot of water that affects the pressure with temperature above the normal rate of gas expansion. This is the case of the aircraft industry.

Bike tyres don´t heat up as much as car tyres do. For a bicycle tyre, the volume of air is very small and usually inflated to high pressure. Any expanding accounted to water molecules will not be noticeable, and unlike high temperature apps, less than accounted on normal air expanding with temperature, which is already very low.

Even on pristine downhill races or road tubular tyres competitions on hot days the pressure discrepancy is negligigle.


This is a major problem in aeroplanes, rare in motorsports and no applicable to bicycles.

Aircraft burnout

Aircraft burnout

When taking off and landing a tyre can get high temperatures and pressure changes. Water vapor content that can boild up increasing the tyre temperature and also elements like oxygen that can react with rubber vapors or wheels metals and become explosively expansive in the presence of enough oxygen. Consider that rubber compounds are highly flammable. In that case nitrogen will be less likely to react avoiding ignition. Nitrogen actually helps to extinguish any fire.

Lifespan of the tyre.

Air if not dried contains moisture that adds to the corrosions concerns of oxygen. Nitrogen will prevent internal rust in parts because there is no oxygen to react with other elements and because we get it dry out of the compressors.

The use of an inert gas could be important in accumulators, hydraulic pre-charge systems, surge suppressors and fire extinguiser bottles but no concern on rubber rusting up.

In any case, performance tyres on cars and bicycles are frecuently replaced though. Note that corrosion is a long-term process.

There is no discussion on airless tyres

There is no discussion possible on airless tyres :mrgreen:

Pressure durability.

Here a question arises: Is nitrogen less porous than other gases and keep the right pressure longer than air?

Air, in fact, is made of 78% nitrogen itself as we said at the beginning of this article. So nobody expects big differences for just a 22% variation caused mainly by oxygen molecules.

But the reality is that nitrogen, being a smaller and lighter molecule than oxygen will last longer inside a tyre unlike the wrong premise of many car repair shops claiming nitrogen bigger size to be the reason to retain optimal pressure longer in compare with air.

How is possible that nitrogen diffuses slower than oxygen contradicting Graham’s law?

Well, nitrogen, despite its minimally smaller size versus oxygen, is more compatable with rubber compounds and less likely to trespass the atomic structure of inner tubes/tyres. Its worse solubility makes the gas to stay longer but do not forget air is still mainly nitrogen!

Nitrogen filled tyres for general consumers if not a scam, will elongate the gas refills periods in a 10%-20% at the most. I have not seen any literature proving its effectiveness in standard environments. Probably at high temperatures moisture can play a key role in the volume of air and pressure, but it sounds like science fiction that replacing oxygen molecules for fatty nitrogen ones is going to reduce the rate at which compressed gas diffuses through porous walls leading to more uniform tyre wear and better fuel consumption.

The cheap stuff. Not to worry :mrgreen:

The cheap stuff. Not to worry 🙂

If nitrogen molecules was way less permeable than oxygen you would get this paradox:

Since oxygen leaks out faster leaving nitrogen molecules inside my tyre, in successive air refills I would increase nitrogen percentage each time. After ten or twenty top-ups my tyres would be mainly keeping nitrogen inside 🙂

Did I say not to bother on bicycle wheels where you can come across with sealant filled tyres to ensure self-healing (and losing air in that process) or very porous latex inner tubes that do not keep the optimal pressure for more than a ride?


On a bicycle the added weight of air per wheel is around 18 grams. Can we cut it down?

Amazingly light Eclipse MTB inner tube

Amazingly light Eclipse MTB inner tube

O2 weights 32 grams/mole and N2 weighs 28 grams/mole. Since air is about 78% N2, the average weight is taken at 28.9 grams/mole, which means you get a ridiculous 3% weight savings in compare to air. Less than a gram per wheel.

Theoretically, hydrogen is 1440% lighter than air (and so is helium – 724%) so we could end up in a almost 18 grams per wheel less. Unfortunately both gases are useless to conserve pressure as explained before.

Why normal air is so good for general purposes?

Because it is made of 78% of nitrogen and air humidity is a minor issue that only counts in high temperature applications.

Mountain bike gear charts

Seeing the rise in interest in new wheel sizes and 11 cogsets sourced it is time to bring up new gear charts for MTB’s.

29ers and 650b wheels have greater circumferences and therefore the distance travelled per crank revolution is modified in proportion.

622mm bead seat rims with 50mm wide tyres (aka 29er) have 11.2% more perimeter than 26 inches wheels (559mm).

As far as for the 650b wheels are concerned (584mm) the discrepance is only 4.5%.

You can still use the old 26 inches chart by multiplying by the factor of 1.112 or 1.045.

Rows:  sprocket size | Columns: ring size

26″x1.95-2.0″ (2070 mm wheel circumference). Classic MTB wheel size

26 inches Bicycle gear Meters of Developement

26 inches wheel chart (meters of developement)

27.5/650b (2160 mm wheel circumference)

26 inches wheel chart (meters of developement)

27.5 inches wheel chart (meters of developement)

29er/700c x 50mm (2300 mm wheel circumference)

29er Bicycle gear Meters of Developement

29er wheel chart (meters of developement)

For further and detailed calculations I suggest this site:

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

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.

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.


Standard 135mm ATB frame with disc and rim brake compatibility


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


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.


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.


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!

monkey_bone_setup_left 3

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.


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.


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.


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.


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.