Alfine Transmission Problems:- Diagnosis Required

[tillson]

Bike: Kalkhoff Pro Connect 2008 Model, Panasonic motor and Shimano 8 Speed Alfine hub gear, 11000 miles.

A couple of months ago, whilst cycling up hill or putting increased pressure on the pedals, they would slip momentarily and this would be accompanied by a metallic crunching sound. Having never changed any of the transmission parts, I renewed the rear sprocket (18 tooth), motor drive sprocket (9 tooth), front chain wheel (41 tooth) and the chain (1/8" KMC).

Everything has run as smooth as silk for a couple of hundred miles since the overhaul. Now I am experiencing the pedal slip again. I have checked all of the adjustments. The yellow lines, line up in fourth gear on the hub, the chain tension is correct, there is good engagement of the chain on all sprockets.

The pedal slip feels like the chain is advancing, or slipping by one sprocket tooth pitch at a time and there is a very, metallic clink sound when this happens. Of course, it's near impossible to closely examine the transmission at the instant when this slip happens and these sorts of sounds tend to be transmitted through the frame and spokes on a bike, making it very difficult to pinpoint exactly where the noise is coming from.

I can't believe that the chain is slipping as engagement is good on all of the sprockets, chain tension is correct and cable adjustment is fine. This only leaves the Alfine hub. The slipping seems to occur in almost all of the gears, but happens with greater frequency when I have changed from a high to lower gear.

I suppose that the Alfine hub could be showing signs of wear at this sort of mileage, especially when coupled with the crank drive. However, I'd like to eliminate / confirm chain slippage before investigating the Alfine hub further. Any tips / tricks for trouble shooting these sorts of problems would be appreciated.

 

[Blew it]

11,000 miles is around the mileage recommended for cleaning and re-lubricating the Nexus geared hub. Apparently it's not particularly difficult to do.

When the old grease is washed out, any metal particals present may indicate a broken ratchet pawl, of which there are several sets in the mechanism. If the washing out is done in an old ice-cream tub, a magnet could then be used to gather any metal particals from the fluid used.

If your really lucky, re-greasing may be all that is required.

 

[JamesC]

Maybe worth checking that the outer sheath of the gear cable is fully seated in the cup at the back wheel when you check/adjust the yellow lines in 4th gear.

A feature of the ProConnect is that the cables pass through the tubes of the frame.

The rear wheel has maybe a centimetre of adjustment which can be used to take up slack in the chain, but in moving the wheel backwards to tighten the chain, a small gap opens up inside the cable cup which is not visible.

The gearchange mechanism can appear to be correctly adjusted on the yellow lines, but is actually a little spongy if the outer sheath can move in the cup on the cassette.

James

 

[tillson]

Thanks. I don't relish the prospect of opening up the Alfine hub. The vision of a lap full of cogs and springs enters my mind when I think about it.

I'll do a bit of Internet searching to see what's involved.

 

[indalo]

Not long ago, I read up a bit on Nexus 8 hubs and the Alfine model came up quite a bit in the search engine results.

As I understand it, 11,000 miles is hugely in excess of the hub service interval recommended. As Blew it has suggested, you may be lucky and get away with a drain and re-lube but there has to be the possibility of some metal fatigue damage to the internals on account of the regular higher loads compared to a non-assisted arrangement.

On checking out the prices, I was surprised to find that the actual hub can be purchased for much less than £200 at lots of stores so, should the hub be uneconomical to repair, a complete built wheel with new hub would probably cost less than a battery for many of our ebikes. I no longer have garage/workshop facilities since moving home so in my case if it happened to me, I'd look for the nearest Shimano specialist where, hopefully, a lubrication service might just cure the problem. If not, they will provide the solution.

To be fair, I think 11,000 miles would probably wear out some components on any bicycle gear system at least once.

Is it new bike time Tillson?


Indalo

 

[flecc]

Changing the hub gear doesn't necessarily mean a wheel build, the entire internal assembly can be swapped into the old hub shell with identical models, so long as the shell is undamaged. It's what I've previously done with SRAM gear hubs, fit the new innards and put the new shell into metal recycling.

 

[Mussels]

This sounds very similar to what I'm experiencing with my Alfine hub and the mileage is similar, I don't have crank drive but it sounds like yours is a bit worse as I can't hear any crunching.
Time to investigate servicing.

 

[tillson]

James

I have just been out and checked that the cable is fully seated in the cup. The cable was a bit tight, and I can understand what you are saying about the effects of it not being seated properly. I've pulled a few millimetres of extra cable through the frame to ensure a nice positive fit, but unfortunately, the symptoms remain. Thank you for the suggestion.

Indalo:

I have a new, unused Alfine hub built into a new wheel rim. It's actually a brand new Pro Connect rear wheel. It's been kicking around in my shed for a couple of years and I was going to sell it. Hence, I have been reluctant to fit it to the bike, but I think that I might have to now. It could tell me if it is the gear mechanism which it playing up.

I don't think I'll be investing in a new bike just yet. I'm still using the original Panasonic battery which is giving me about 40 miles range on the lowest power setting, and my commute is 20 miles, so plenty of margin there. Anyone buying it second hand would be quite rightly put off by the 4 year old battery, making the rest of the 4 year old bike worth very little. Knowing the bike as I do, it's worth a lot more to me personally.

flecc:

Will the innards extract from the hub shell as a complete assembly? It might be worth while having a look inside to see if there is any evidence of swarf / broken metal which may indicate that something has failed.

 

[flecc]

Normally yes, but I've never had an Alfine hub apart and there are series differences in the left hand side of the internals. If you have a look at this tech document, you'll see a box in the centre numbered 1 in which there is the "internal assembly" that swaps all the gear parts straight over, the rest of the bits being a sequence of reassembly.

However, look to the upper right and you'll see a box showing A and B type hub shells with advice, so clearly it will need to be the same type or you'll need further advice on the change.

Also, since you've had yours for a while, I've assumed its the SG-S500 hub, but if you look on this link you'll see there is also an SG-S501 version which does not have the A or B problem. Which one should be marked on the hub shell. In each case click on the first blue numbered link for the appropriate document.

 

[tillson]

Normally yes, but I've never had an Alfine hub apart and there are series differences in the left hand side of the internals. If you have a look at this tech document, you'll see a box in the centre numbered 1 in which there is the "internal assembly" that swaps all the gear parts straight over, the rest of the bits being a sequence of reassembly.

However, look to the upper right and you'll see a box showing A and B type hub shells with advice, so clearly it will need to be the same type or you'll need further advice on the change.

Also, since you've had yours for a while, I've assumed its the SG-S500 hub, but if you look on this link you'll see there is also an SG-S501 version which does not have the A or B problem. Which one should be marked on the hub shell. In each case click on the first blue numbered link for the appropriate document.

My hub is the SG-S501. I have followed the links to the data sheet thanks. I can't see how the internals are held inside the hub, there doesn't appear to be any clips, only dust caps. I'll have to strip the wheel down again, removing the sprocket and see if the method of stripping becomes evident.

 

[banbury frank]

Hi NEW hub £120


Shimano Alfine SG-S501 Internal Geared Hub - Center Lock - Without Fittings 32H | eBay

Frank

 

[Mussels]

Hi NEW hub £120


Shimano Alfine SG-S501 Internal Geared Hub - Center Lock - Without Fittings 32H | eBay

Frank

I think it will be time to buy a spare after payday.

 

[shemozzle999]

I would first check the chain link by link for free operation.

 

[flecc]

My hub is the SG-S501. I have followed the links to the data sheet thanks. I can't see how the internals are held inside the hub, there doesn't appear to be any clips, only dust caps. I'll have to strip the wheel down again, removing the sprocket and see if the method of stripping becomes evident.

They always look vague in the diagrams, but basically the left hand side nut holds the assembly in place within the hub via that l/h bearing. I don't know the retention details for the Alfine parts on the r/h side, but no doubt that will become apparent as you delve into it.

 

[tillson]

They always look vague in the diagrams, but basically the left hand side nut holds the assembly in place within the hub via that l/h bearing. I don't know the retention details for the Alfine parts on the r/h side, but no doubt that will become apparent as you delve into it.

Thank you. I had a quick look at my spare and can see the LH nut, the RH side looks a bit more complicated. I am hoping that all the RH side will all come away as an assembly. I'm not going to experiment on the new one, I'd better save that for the suspect unit.

 

[Teejay]

You Tube video on stripping an Alfine-8
Bicycle repair. Shimano Alfine oil bath lube job.. - YouTube
It's not brilliant, as he hadn't given enough thought as to where to position the camera but it might help. Looking at the instructions, it seems the important thing to bear in mind is that this large dust cap (12 in the Technical document) has a left-hand thread. Shimano do a tool (40 in the Tech doc) to help undo it but from what I've read, people use a hammer and old screwdriver or just brute strength to do it!

 

[JamesC]

It will be very interesting to see the condition inside your hub after 11,000 miles. The U tube video in Teejay's post shows the condition of a hub at 6,000 km, which had been relubricated at 3,000 km.

Lubrification of Shimano hubs has always attracted a lot of discussion.

The latest 11 speed hub is the first that is fully sealed, and uses an oil bath. The 8 speed (Alfine and Nexus) are lubricated with grease at manufacture, but an oil immersion is available for subsequent maintenance.

The U tube video shows Mobil ATF (automatic transmission fluid) being used which seems to be popular in the USA. The American MTBR forum has a sub forum dedicated to Internal Gear Hubs with several members opting for this as an economic approach.

It seems that stripping the hub down to the level that each individual item can be lubricated with grease might be impractical. The video shows a sensible compromise of greasing the accessible bearings, and dipping/draining the main gear assembly to allow lubricant to reach the inner areas.

There is no doubt that the official Shimano Maintenance Oil Set which includes Shimano Oil and an Oil Bath Container is pricey at £80, but maybe offers a quick solution to frequent lubrification of the internal assembly without the need to rebuild the wheel.

Note the height of oil required in the oil bath to cover the relevant area is 95 mm.

Grease seems to have been blamed for some gear failures in very wet conditions, but 11,000 miles in all conditions seems good going to me.

Look forward to photos Tom !

James

 

[tillson]

I am a bit short of time at the moment, so have decided to fit the spare rear wheel with the new gear unit. I've just ordered a new Cassette Joint Unit and sprocket so that I can build it up and swap it over as a complete unit. When time permits, hopefully within the next couple of weeks, I'll open up the old one and have a look what is happening inside. I will take some photographs and post them on here.

That You Tube video is very informative, but the man's beard and elbow gets in the way at critical moments, but thank you for posting Teejay. A friend has sent me a link to another article on stripping these types of hubs. When coupled with the video at Teejay's link, I think it just about covers everything.

Link here

 

[JamesC]

Excellent link - thanks

James

 

[tillson]

Well, an opportunity to have a look into the slipping gear problem has presented itself this afternoon. However, I have just taken the bike out for a quick run and there was no sign of the problem whatsoever. Not convinced, I carried on with the ride and replicated the 20 mile round trip to work and back. There was not a single hint of a problem, just silence coupled with smooth and precise gear changes. I even put the bike in the, hardly ever used, high power mode and pedalled as hard as I could up hills in an attempt to stress the gearbox.

Last week, I had seven consecutive days of crunching and clicking accompanied by slipping pedals. There was not a single mile during those seven days when this did not happen and the bike was bordering on unrideable. The only thing that I have done since then is to lock the bike in the garage at 6:30 pm last Thursday evening and leave it there. Today I have come to it and it appears to be fixed.

I detest faults like this. If it is broken, I wish that it would just break and act broken. Now I have the dilemma of either leaving apparently well alone and risk the bike letting me down when I most need it, or to wade in and start pulling the hub apart.