How does shimano alfine work

Oil lubrication is desirable for an internal-gear hub, if the oil is replenished and changed regularly. However, it is possible to lubricate the Alfine 11 better than Shimano suggests. As "jb" points out in the CTC forum see link below , the standard oil-change procedure does not thoroughly clean wear particles out of the hub. Partial disassembly of the internal mechanism allows a thorough cleaning and wear inspection. Following this, spot lubrication of internal moving parts is advisable so they are ready to go with the first pedal stroke: oil injected from outside can take a while to reach them.

Lubrication of ball bearings with waterproof grease is also desirable. Finally, the hub is reassembled and oil is injected through the port. The large right-side bearing seal of the Alfine speed hub often leaks. Some hubs have been almost completely dry when opened up for inspection. Changes in temperature and atmospheric pressure can pump oil out of the hub. Storing the bicycle under shelter, but where temperature is near that outdoors, can reduce leakage. Adding oil between oil changes will keep a leaky hub lubricated.

Leaking oil can be messy, and if it runs down the spokes, it can make a rim brake squeal and grab. Aaron Goss recommends laying the bicycle on its right side with a rag under the hub for storage or transport, to catch leakage. Shimano oil is expensive.

Phil Wood oil has been used with success. It is viscous, and reduces leakage. Automatic transmission fluid also has been used. It is quite watery, and so more prone to leakage, but preferable in very cold weather. Nonstandard lubrication will void the warranty on the hub. This documentation is available in pulditple languages -- there is a language selector on the Web pages. Shimano lists the parts of the internal mechanism only as modules. In the Alfine 11 hub, all the planet pinions run on roller bearings as per Alfine 8, premium Nexus 8 and Rohloff hubs , so as to decrease losses.

Once again as in the Nexus 7 , Shimano has avoided having a nice efficient direct drive gear 5 or 6. As it is, the hub uses a single gear train in gears 1, 7, 8, 9, thus these are likely the most efficient gears. Two gear trains are used in gears 2 ,3, 4, 10, 11 medium efficiency , and three are used in gears 5 and 6 probable lowest efficiency. Roller-clutch drag should probably be least in 8th and 9th gears, which use only one of the three gear trains, so the roller clutches for the other two are engaged..

If the gear ratios are set in a vaguely sensible fashion i. On a heavily loaded touring bike, gear 1 is likely to be heavily used too. This being the case, the weighted average efficiency of the gear may not be as bad as the numerical average efficiency might suggest. Because the Alfine speed first-stage gear teeth are cut helical instead of straight, there is a question about the efficiency of gears , as axial thrust loads must be supported by non-rolling-element bearings.

Some folk have suggested that there ought to be more gears yet with different clutching because there are sixteen possible permutations of four clutches but the two sun gears of the second stage cannot be usefully locked at the same time. Unity ratio in all three stages is the only allowable and unused combination. In addition to the drag from the gears and roller clutches, there may be drag from the bearing seals.

Drag from the large bearing seal on the right side is highest when coasting, or in the lowest and highest gears, which are farther away from unity ratio. There are some very helpful instructions and photographs prepared by jb in the midst of the long running Alfine 11 thread on the CTC forum.

K member forum. The cable shift control is very sensitive to variations in build tolerance and adjustment. The reason for this is that the cassette joint may only rotate about degrees total, i. This limitation occurs because the right-hand hub cone is supported on two prongs, leaving gaps that the selector mechanism pokes though This makes building the hub accurately very difficult for Shimano and also makes it sensitive to the exact external setting when in use.

The helical stage 1 gears were presumably added at a late stage the EV tech doc shows straight-cut gears , I suppose to make the hub nice and quiet. However this generates an axial thrust load which can cause problems with retention of sun gear 1 on the axle as jb has described in the reliability thread.

Arguably, whoever designed the gear train screwed up here, in that when you pedal hard, the sun pinion S1 is forced rightwards against the retaining clip, rather than leftwards against a fixed shoulder. Maybe there is a good reason for this, but if the helical gear had been cut the other way or left straight-cut , this fault might not occur in the same way or perhaps at all.

The problem is especially likely if you routinely pedal hard in gears Numerous users have reported skipping in some gears. This can happen even if the sun-locking pawls are fully extended in new hubs or hubs where there are burrs on the pawls but it certainly will happen if the sun-locking pawls are not fully extended.

If the build tolerances of the hub are off a bit, the hub can therefore slip even when 'correctly adjusted'. The same problem occurs in numerous Nexus and Alfine 8-speed hubs. Many users have found that a little trial and error with adjustments that are up to about 1. However, if the axle assembly is examined when out of the hub, the pawl lift and therefore correct adjustment can be checked directly.

I do not know whether the same fault occurs with Alfine speed hubs. Note also that the sun-locking pawls in an Alfine speed hub are less likely to be overrun than in a Nexus or Alfine 8-speed hub, so any burrs on the pawl tips are unlikely to be knocked off when that pawl is not transferring drive.

Hard i. Stage 2 and stage 3 could jam entirely and you would still have some working gears, but if stage 1 starts to jam you are in trouble because the sun S1 is locked to the axle and the stage-1 gears must turn at all times when you are pedaling.

As already mentioned, these hubs often leak oil. It isn't clear where the hub is meant to be vented; it seems to me that some leakage most often on the right-hand side is more or less inevitable. Because the hub is oil-lubricated, water incursion is less likely than with the 8-speed Nexus and Alfine hubs -- as long as the oil isn't allowed to leak out till little is left.

The electrical connection for the motor unit does not withstand repeated disconnection and reconnection, which is necessary to replace a tire or disc rotor, etc. A video linked at the end of this article describes this problem in detail. So, with one or two caveats, the internals ought to be reasonably reliable; an intrinsically 'bad hub' ought to become evident within the warranty period.

However, the efficiency is rather low in many of the ratios, the helical gears are probably not the best choice for high torque use in low gears, and a significant proportion of users reports skipping or other problems, which can arise for several reasons. If a Gates drive belt is overtightened, it can interfere with shifting, at least on the 8 speed hub. Also see Aaron Goss's comments below about problems when it is not tight enough. On price and performance the Alfine hub is excellent.

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You can expect the latest news and features, in-depth reviews from our expert team of testers, impartial buying advice, how-to tips and plenty more. Shimano Alfine Disc Hub review. Latest deals. Shimano sells a special tool TL-S for this. Whether it is worth the price is for you to decide. The oil can be replaced through a hole with a syringe.

Shimano sells an oil change kit with syringe, cup and oil. This kit is quite expensive, but you can't just use any oil, as it needs to have a certain viscosity and not damage the rubber seals inside the hub. Using any other oil will void the warranty. Nevertheless, some people are using Rohloff oil, which is sold in larger quantities and is significantly cheaper. The Rohloff syringe also fits the Alfine Inter 11 hub and procedure is exactly the same.

As an added bonus the Rohloff oil is biodegradable, while Shimano's oil is probably not. Step by step instructions with pictures for changing the oil My Own Experience with Rohloff Oil As the user manual suggests, I replaced the oil of my hubs after kilometers. The oil that came out was full with sparkling aluminum specks.

I used Rohloff oil which has separate oils for rinsing and lubrication. The rinsing oil also had aluminum specks in it. After about a year I started to notice a faint crackling noise coming from the rear of the bicycle.

The sound was only present in sixth and seventh gear, indicating that the sound was coming from inside the hub. When changing the oil at the end of the season between 10 and 15 milliliters came out, the rest had leaked out. There were no noticeable aluminum specks during the second oil change. Immediately after the oil change the crackling sound persisted, but it soon subsided, and the hub has been smooth and quiet since. This is good opportunity to do a thorough inspection and make some small adjustments.

A clean bicycle also keeps your hands clean when you have to touch it for transportation or repairs. The Alfine 11 hub is in particular dirty area of the bicycle. It is normal for some oil to leak out around the seals on the right side, and then there is the chain which also usually one of the dirtier parts. A thorough way to clean the hub is to remove the wheel from the bicycle, then disassemble much of the hub and use an ultrasonic parts cleaner to clean the parts.

If you want to leave the wheel in the bicycle, I recommend the following method: Useful cleaning supplies Rag; a cloth made out of fabric that can absorb grease and grime. Small blunt stick for wrapping the rag around, preferably made out of food or plastic that will not scratch anything. Spray bottle with mild degreaser liquid. Cleaning instructions Start with a dry rag and wipe down the spokes, which are usually covered by oil and dust. Take the rag, holding one end in each hand and put it between the hub shell and sprocket.

Move up and down like flossing teeth until there is no more visible grease on the seal when you look from above. Now rotate the rear wheel a little bit and clean until you have gone all the way around. Put a tip of the rag around the axle on the right side between the cassette joint and the frame and again use a flossing motion to clean all the way around. Wipe of any grease from the cable.

Push the pulley handle to get some slack on the cable if you want to clean it around the end. To clean the right side of the sprocket wrap the rag around the tip of your finger, or a stick if your fingers are big and wipe the sprocket while rotating the pedals backwards.

Clean the teeth on the front where there is no chain on them. Now that the worst dirt is gone, work on the plastic dust cap. This is where a lot of oil accumulates. First wipe it down as much as you can. Pull it out towards the sprocket. Underneath you will find more oil. Wipe it down as much as you can. There are many nooks and crannies here.

Some mild degreaser may be applied, but be careful not to get it on the chain or anywhere else. When sufficiently cleaned, put the dust cap back on.

The hub shell can be cleaned with a damp cloth, or some liquid soap if you want to be thorough. Pay attention to the edge of the spoke nipple. A small tooth brush may help cleaning around the spoke holes. Dry if off with soft cloth for a shiny finish. The left side is not as dirty as the right side. There is still dust, but not as much oild and grease. There are still many books and crannies. Be careful around the disc brake rotor, the edges are sharp like a knife and can easily cut your fingers.

Try not to get any oil or grease get on the rotor. If you do, use a degreaser to clean it off. Sprocket replacement You can replace the sprocket on the Alfine hub once the teeth wear out.

If you are satisfied with the range of your gears you should get one with the same amount of teeth. If you want to make climbing mountains easier, you can replace the sprocket with a large one with more teeth. If you want to go faster, replace it with one with less teeth.

The Alfine sprocket S comes in only 18 or 20 teeth, and has a plastic chain guard around it. Shimano recommends using this sprocket when using the CT-S chain tensioner, which you would only need if your frame has vertical drop outs.

If you have another way of tensioning the chain you can also use sprockets meant for the Shimano Nexus hubs on the Alfine hubs.

These sprockets come with 16, 18, 19, 20, 21, 22 or 23 teeth, they are often a bit cheaper as they don't have the plastic chain guard. The Nexus sprockets are dished, meaning that depending how you put them the the teeth on sprocket go inside or outside.

This allows you to line it up with the chainring on the crank for a better straight chain line. Shimano recommends a ratio of around 1. Meaning that the chain ring should have almost twice as many teeth as the rear sprocket. A lower ratio means that the whole gear range is lowered, making it easier to climb steep ascends. It also allows you to apply more torque on the mechanism inside the hub, going below the manufacturer recommendations may increase wear or increase chance of failure.

My own bicycle came with a 18T Nexus sprocket installed with a 32T chainring from the factory, that is a ratio of 1. There seems to be no adverse affects after two years. I have since then installed a 19T on my girlfriend's bicycle ratio 1. Two different readers messaged wrote to me to tell me that they used a 22T sprocket with a 32T chainring which have a ratio of 1. One did 5, kilometers, the other 14, kilometers at the moment they wrote to me and did not run into any issues so far.

My take on this is that the recommended ratio of approximately 1. If you need a lower gearing range, don't let this recommendation stop you and just install a larger rear sprocket. Chain Tension Because there is no derailleur to hold the chain tension the Shimano Inter 11, like any other internal gear hub requires another method of keeping the chain tensioned.

Bicycles that come equipped with a internal gear hub usually heave adjustable or horizontal fork end, or come with an eccentric bottom bracket to keep the chain tensioned. These require regular adjustment as the chain stretches over time. Compatible chain tensioners For bicycles with vertical drop outs Shimano also offers an Alfine branded chain tensioner CT-S which replaces the derailleur.

The CT-S is smaller, but according to one review also requires regular adjustment. Various other manufacturers sell chain tensioners for single speed and internal gear hub bicycles that will also work with the Alfine Inter Chain tensioner Shimano CT-S View product on Amazon.

Like other drive trains the efficiency decreases at lower watts and becomes more variable as the resistance of other parts of the drive train remains the same and take up a large part of the total resistance. The tests were conducted using a home built testing rig, and comes with some disclaimers. There are many variables influencing the efficiency, there was a limited sample size and the data had quite a bit of noise.

Variables include manufacturing differences, how worn the parts is and the kind of lubricants used. All these factors can influence the efficiency. A well maintained derailleur gear drivetrain would be able to get close to that, depending on the added drag by the derailleur jockey wheels and the chainline. In some of the lower gears its performance is equal to the Alfine The 18 speed Pinion gearbox is less efficient in lower gears and more efficient in the higher gears.

In conclusion, the Rohloff Speedhub has the a greatest range, it has a higher or equal efficiency in every gear, and is the best of all internal gear hubs in this test. The Alfine 11 takes second place. It excels in the 3 lowest gears.

When climbing up a hill, you need every bit of power, so it seems like a fair compromise that you get less efficiency in the higher gears which you will use on the way down, or with the wind in your back when high efficiency is less of a necessity. Operating efficiency comparison chart per gear for Rohloff Speedhub and Shimano Alfine 11 speed. Thick lines are watt, thin lines 50 watt. Efficiency tests of various internal gear hubs in German Efficiency tests of various internal gear hubs - part 2 in German Comparison of the "upper class" of internal gear hubs: Alfine 11, NuVinci and Rohloff in German Reliability Since the hub has been on the market for a few years there is little information about the long term reliability.

On the internet there are various anecdotal reports of hub failure, but there are no statistics on how common this is, and under which circumstances the failure occurred. Compared to Rohloff Speedhub The Rohloff Speedhub has proven itself to be quite reliable over the years. In , when the Alfine 11 speed was new, Elan, the importer for Rohloff hubs displayed various internal gears and bearings of both hubs at the Bike Motion trade show, to show that the beefier components for the Rohloff are more durable.

The article states that helical gears that Shimano uses for smoother and quiet shifting wear faster and are less efficient. One commenter on the page points out that helical gears have been used successfully in transmissions for automobiles, and that with proper lubrication they work fine.

Another commenter points out that that Rohloff's lowest ratio is 0. This means that more torque is generated in the lower gears, with the same power input, put more strain on the transmission and requiring sturdier components.

It is also pointed out that Rohloff markets its hub for off-road use, while Shimano does not. When used according to instructions of the manufacturer there is little reason to assume the Shimano hub will be less reliable.

In addition I have also maintained the hub on my girlfriend's bicycle. Known problems Since Shimano does not publish any information about failure rates and problems. It is unclear how widespread issues are. Leaking oil It is normal for the hub to slowly leak oil over time. That is why the oil needs to be changed as part of a normal maintenance cycle. My own experiences and many reports on the internet indicate that the amount of oil leaking varies per hub. Some owners have had so much oil leaking that it covered the disk brake rotor, and had the hub replaced under warranty for it.

Some people have suggested that there is a quality control issue with the seals, some hubs come with bad seals and leak excessively. Online discussion about Alfine Inter 11 hub reliability Internals The inside of the Alfine Intern 11 contains an axle with pawls that move the gears around in order to switch gears. Some of the gears are helical, allowing the teeth to grab each other more easily while shifting. When switching between the sixth and seventh gear the clutch moves from the right side further towards the middle.