Alfine 8 speed - servicing

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Moodyman1

Alfine 8 speed - servicing

Postby Moodyman1 » 7 Aug 2012, 2:59pm

My 8 speed Alfine has done 4000 miles. It was serviced after 2500 miles by the shop with Shimano grease.

Last week, I serviced it again – but I used Auto Transmission Fluid (ATF) as is commonly advised on forums. I then greased the bearings before putting it back together. Before I put it back together, I checked the cogs and there was no play.

But after mounting the hub back on the bike and doing 3 commutes, I noticed that:
* The gear change is super slick
* The hub is silence when freewheeling and gears 5-8 are whisper quiet whilst pedalling.

BUT…

Gears 1 & 2 make a loud whirring noise (bordering on grinding) – especially when cadence is low – i.e. uphill (70-80rpm). Gears 3 & 4 make a quieter whir when the cadence is low, but this disappears when the cadence is 90+. I’ve checked and double-checked to make sure the nuts are not overteightned or too loose.

Is it simply a case of ATF being thinner and less viscose than grease so not as good as silencing the hub or should I be worried about this noise?

Brucey
Posts: 35161
Joined: 4 Jan 2012, 6:25pm

Re: Alfine 8 speed - servicing

Postby Brucey » 7 Aug 2012, 5:03pm

with thinner lubricants there will be more noise; and you may have been listening out for it too. Having said this though...

ATF has been widely touted as a suitable lubricant for Shimano hub gears.

I am not convinced; I am sure it is better than nothing, but remember we don't know what shimano's special oils and greases really are because they are not telling.

ATF is specified for a lot of car gearboxes (not just autos) and on some where the gearchange is a bit reluctant you can use other oils instead. In that you may really want shick shifting and good protection under high contact loads, the requirements for some car gearboxes and those of hub gears are quite similar.

To offer good protection and slick shifting, an oil which has relatively high viscosity under high pressure, but low viscosity under low pressure will achieve both goals. Thin though it seems to be, most conventional ATF has more or less the reverse characteristic; remember that they have to work inside torque converters, as well as lubricate gears etc. It is my understanding that conventional ATF does not offer the same performance under high loads as (say) a GL-4 gear oil.

Specialist gear oil manufacturers offer fully synthetic ATFs that equal GL4 gear oils for protection at high loads. They also offer multigrade gear oils that are inviscid at low strains and temperatures (and thus shift well, even when cold) but still (they say) outperform conventional gear oils under higher loads and temperatures.

You can read more here;

http://www.redlineoil.com/content/files/tech/Gear%20Oil%20Tech%20Info.pdf

how much of this is hype and marketing BS, goodness knows. But there is much science behind lubricant design and selection for some applications.

Although hub gears run 'cold' the local contact pressures and temperatures -for a fraction of a second at least- are much higher than might be supposed. Much of the argument for low temperature car gearbox oil perfomance applies to bicycle hub gears, too.

Shimano may have designed their gears to be very tolerant of lubricant type, but I doubt it. I would be looking to use the correct lubricant as specified or failing that, the best quality gear oil.

The only thing that would stop me from chucking in gear oil with all its lovely additives is that some of these additives may have materials compatibility issues. Brass or bronze parts don't like high temperatures and GL-5 specification lubricants, for example, which is OK because those materials and temperatures don't exist/persist in hub gears. However with polymer parts (and the original grease remnants) there are no guarantees of compatibility with gear oil; or ATF, come to that. :roll:

I am using a semi-fluid grease in one of my hub gears at present; this has a thixotropic nature (so won't leak out of the hub at rest) and has solid lubricants, EP additives etc in it. Initial signs are encouraging, but I've only run it for a few hundred miles thus far so it is early days....

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

mabonzo
Posts: 1
Joined: 8 Aug 2012, 7:03pm

Re: Alfine 8 speed - servicing

Postby mabonzo » 8 Aug 2012, 7:19pm

I have used ATF for a year on my alfine 8 speed with no issues during that period which have included commuting and XC riding. I have just serviced the hub and it is looking good. The only issue I initially had was leakage from the non drive side, probably because I put in too my oil to begin with. The addition of bathroom sealant helped sort out this problem. As to whether ATF is better or worse than other lubricants, I suspect the discussion can get quite academic. I have gone with it as works for a car gear box which has much higher stresses and it is inexpensive unlike Shimano branded lubes. See other forum threads http://forums.mtbr.com/internal-gear-hu ... 70119.html

Ribblehead
Posts: 366
Joined: 21 Jul 2011, 3:08pm

Re: Alfine 8 speed - servicing

Postby Ribblehead » 9 Aug 2012, 6:58pm

Brucey wrote:we don't know what shimano's special oils and greases really are because they are not telling.


If Shimano grease is covered by COSHH then Shimano will have to provide a Material Safety Data Sheet under UK law.

Has anyone ever asked for an MSDS?

Ribblehead
Posts: 366
Joined: 21 Jul 2011, 3:08pm

Re: Alfine 8 speed - servicing

Postby Ribblehead » 9 Aug 2012, 7:02pm

mabonzo wrote:See other forum threads http://forums.mtbr.com/internal-gear-hu ... 70119.html


Step 7: Put the hub in a bath of petrol


Here's hoping there's nothing in the hub that will take exception to being dunked in unleaded! Obviously it's mostly metal, but maybe the needle bearing cages are plastic?

By the way, doesn't unleaded smell revolting compared to the old four-star :(


Edit: Welcome to the forum Mabonzo!

Moodyman1

Re: Alfine 8 speed - servicing

Postby Moodyman1 » 9 Aug 2012, 11:26pm

Well picked up some Gl4 gear oil for £ 3.50 from Wilkinson's. It much thicker than ATF. Gl4 is like treacle whereas ATF is water-like in comparison. Will let you know how the hub feels after servicing this weekend.