Brompton BWR hub maintenance

[wafter]

As per my post in the thread dedicated to my own example, pulling the indicator chain from the hub revealed some decidedly grey and manky looking oil on its end.

This led to thoughts of cleaning out the existing lubricant now it's run in (and the lube will be contaminated with all the resultant particulates) and re-lubing. While not the same, Shimano apparently suggest an oil change on their 11sp Alfine hub at 1k km, then subsequently every 5k km or two years.

Information for the Sturmy-Archer hubs seems less forthcoming / a lot more convoluted; with some running with oil, some grease... the BWR apparently using grease and requiring "no maintenance" although I'm skeptical.

Since the unit is doubtless now outside what could be considered a "running in" period I'd like to see it cleaned and re-lubed.. preferably with oil as this seems like a better choice for this sort of transmission than grease.

If anyonw has any experience of such work on their BWR hub I'd be very interested to hear more

 

[Chris S]

The Brompton BWR hub is the same as the Sturmey Archer NIG (no intermediate gear) hub. Here's a video showing a complete strip down and rebuild.

View: https://www.youtube.com/watch?v=7Y-WiiCDBqs&list=PLv-LgXuO5dtTj1uDEruX04EC_OC-UH228

 

[tinywheels]

wow,that looks like a mission. My hub seems OK for next to no maintenance. That's unless the bike shop service includes a lube of some sort

 

[a.twiddler]

Something that always puzzled me was why the modern generation of internal gear hubs are not made with oil ports like older SA models but apparently greased for life. At least with a drop of oil added every month or so any excess might help wash out any swarf that occurs. Grease would seem to be just the thing to attract and retain it. At least with a hub with a toggle chain you could lean your bike over and drip some in past that.

I would hope never to have to take one to bits but if I did, It seems easy enough to drill and tap the shell while it's apart and fit some sort of oil port, making sure to clean up any swarf afterwards.

 

[EltonFrog]

I’ve taken a few of the old SA hubs apart but not the BWR yet. How hard can it be? 🙄

 

[Chris S]

@wafter Here are some photos so you put the pawls and springs back in the right way.

 

[a.twiddler]

Come to think of it, hub gear bikes have stealthily crept up on me over recent years as they seem to be "the thing" with recumbents. I went from none to to four! One Sachs 3 X 7, one SRAM 3 X 8, one Shimano Nexus 7 and a Sturmey Archer 3 speed on the Brompton. The only one I couldn't get oil into if I wanted to is the Shimano, without dismantling. They've all worked fine so far.

 

[Tenkaykev]

Mrs Tkk mentioned her plan to get Ben at Kinetics to transplant the 14speed Rohlof on her touring bike to one of her Bromptons. Should be interesting and I'll get to ride it too.The Rohloff has an oil port and I have changed the oil on several occasions over the years.

 

[wafter]

Thanks all

This has proven to be this weekend's tangential rabbithole; bit of a brain dump below...


It seems that these hubs use grease rather than oil to reduce the need for regular maintenance (oiling) and make them cleaner as oiled designs aren't totally sealed so leak to a small extent. The downsides of grease are that it can migrate away from areas of load and dry out over time. There's potentially also less natural "flushing" action compared to oil since it all stays inside the hub and will retain contamination. It also needs to be applied directly to components, meaning more disassembly if re-lubing.

So, oil requires frequent if minmal attention and is a bit less convient but should last forever. If it did need attention, this could probably be achieved by flushing and re-lubing without disassembly. Grease remains maintenance-free for a longer period of time, but will ultimately require stripping; cleaning and re-greasing.

Thixotropic or semi-fluid grease appears to mitigate these issues somewhat as it becomes less viscous under load, meaning potentially better coverage and distribution in use, but less chance of migration and leakage when static.

There's a thread on the CUK forum in which a landrover swivel pin grease is recommended. Its also suggested that its viscosity can further be modified by adding gear oil (presumably mineral-based). Another suggestion is thinning out CV joint grease (which contains a lot of moly) with gear oil, but this probably doesn't display such desirable thixotropic properties.

I like moly as it's great under high loads (hence the CV joint application), although it doesn't seem that prevalent in automotive gearbox lubrication. I did find a Molykote product for (presumably non-automotive) gearboxes which contains moly. It's possible / likely that the Landrover stuff mentioned above might also (a video containing some seems to back this up given it's colour).



What's on the end of my gear indicator chain is a uniform dark grey and somewhere between CV joint grease and oil in viscosity.. so could well already be something like those described above. It doesn't look visibly contaminated and I can't really feel any roughness between my fingers..

While I'm wary of "sealed" / claimed "low maintenance" products it seems that what's in there should legitimately last a decent amount of time, and I can' add the odd drop of mineral oil down the axle periodically to ensure it doesn't become too thick.

Further down the line / when time allows / when I have the spuds to sufficiently disassemble it, I can look to strip, clean and re-lube the hub - for which I'll apparently need a Sturmey Archer HTR 145 Classic Ball Ring Spanner in addition to some cone spanners.

 

[FrankCrank]

I have several SA 3 speeds. On occasion, I have to remove the indicator chain, and the spindle always has a coating of greyish oil, so would think this quite normal. I add a few drops of engine oil occasionally, through the indicator port. Any more, and it will seep out and make a real mess.
On very old hubs that have been left idle for years, or even decades, they can be gummed up with old oil. Flushing them out with spray lube into the port is all that's needed, then a few drops of oil to finish the job. They really are bombproof, and require little by way of maintenance, let alone a complete disassembly.

I can't imagine the Brommie one being any different really, but if you feel like having a go at a full dismantle and re-lube, then why not

 

[Gunk]

I add a few drops of engine oil occasionally, through the indicator port

that’s all I do , and as soon as you drop some oil in, it definitely runs smoother.

 

[EltonFrog]

The last SA hub I did old grease had bunged up the pawls making the gears slip in 3rd. https://www.facebook.com/share/p/AyFey45j9tXFS97v/? If you’re on Facebook there’s a little before and after video.

 

[Chris S]

Further down the line / when time allows / when I have the spuds to sufficiently disassemble it, I can look to strip, clean and re-lube the hub - for which I'll apparently need a Sturmey Archer HTR 145 Classic Ball Ring Spanner in addition to some cone spanners.

You can just use ordinary 16mm spanners to undo the cones, or even an adjustable wrench. You don't need a ball ring spanner either, you just use a hammer and punch like this.

View: https://youtu.be/ea6krXSs-lc?si=cIfTKROwK8jt5_hb&t=117

 

[oldwheels]

A while ago I had a SA 3 speed which was gummed up due to being left for a long time unused. The advice I got was to fill the hub as far as possible with WD40 and give a spin every day for a couple of weeks then lay the wheel on it's side to drain and repeat this procedure once more.
After draining for the second time fill half way with heavy gear oil. Some will inevitably leak out and be a bit messy initially but that can be allowed to happen on the bench before fitting a tyre.
Worked for me and the hub went on running as long as I had the bike which was a bit of a workhorse for a couple of years.

 

[rogerzilla]

The modern greased ones are "sealed for life" but "life" means until the hub dies. The old oiled ones, if ridden with a modicum of sensitivity, last for ever on a drop of oil a month with no need to ever open them up. The one on my commuter hasn't been opened since 2008.

So...it needs to be totally disassembled at least every two years ( SA say annually), degreased and cleaned, then reassembled with the correct greases. The internals need the SA brown semi-fluid grease - it's more like a very thick oil - or an equivalent (the stuff I used is pictured) and the axle bearings need normal lithium grease.

This is a DIY job as most shops won't get involved in hub gear repairs.