Automatic BWR hub gear

[mitchibob]

No matter how I adjust it, my Brompton BWR hub seems to have developed 'automatic' properties, depending on level of torque. i.e. the middle gear seems to slip to the lower unless there's a certain amount of torque, and which point, I'm back into those more direct-drive gears. It has occasionally changed back up mid-27% ramp, but that could be I've somehow knocked the gear-changer in my desperation.

This hub has worked well for nearly all of it's 24,000km or so, but only seemed to have this problem after it wasn't ridden for a couple of months due to injury. I need replace both rims at the moment anyway, and might just get a replacement BWR hub at the same time, but interested if anyone has had similar experience and might point me at something I'm missing. I'm tempted to try and learn to service hub properly. It's just outside my bike repair comfort zone, but I feel this hub has a lot of distance left in it.

 

[rogerzilla]

It is usually cable adjustment, or a sticky cable, so look at those first.

These hubs are supposed to be stripped and serviced regularly, and they can get very gummed-up internally if they're not. Bike shops won't generally service hub gears, so it's a DIY job. Buy a new pawl actuator (or a whole driver assembly) in advance as it is the most troublesome part of the hub, and almost impossible to clean without bending it.

 

[12boy]

I had an SA 3 speed hub get funky and left with my LBS dude who wasn't too familiar with them but YouTubed the crap out of the subject until he fixed it. The process apparently required 2 different types of grease. Not I liberated an old AW hub from a trashed Schwinn and noted it had an oil port. I think Sheldon Brown offered some guidance that if your SA hub is portless you can apply oil through the axle after removing the shifter mech. Being too lazy to disassemble my hubs, I have done this, applying a few ccs of synthetic 5-20 auto oil whenever the hub has become a little noisy. It has worked just fine for at least 5 years.

 

[u_i]

You get get Shimano Internal Hub Grease for about $20 per container.

 

[mitchibob]

Thanks for advice guys. It's definitely not sticky cable, as when come to a stop and hub isn't under torque, it changes back down, and have fiddled with the adjustment enough that fairly certain it's not that now, especially as it tends to behave differently on stand compared to under actual riding torque. I might treat myself to a new one until I've sorted a little workshop to strip it properly... probably find it's managed to get some cat-hair in there (it got everywhere else).

Fairly certain the auto-change up at 27% is my knee knocking the changer though! ;-)

 

[rogerzilla]

Can anything be tugging the cable? Is the rear hinge really worn? "Auto changing" was sometimes a problem on hard-ridden clubman bikes due to frame flex, and is supposedly why the preferred cable routing on diamond frames was along the top tube, around a roller, then down to the hub, all in bare cable except for the loop between the trigger and the fulcrum clip at the front of the top tube.

 

[berlinonaut]

I might treat myself to a new one until I've sorted a little workshop to strip it properly...

In case you want to do it yourself:
Here's the parts scheme https://brommieplus.com/portal_b1_page.php?owner_num=b1_408821&button_num=b1&cnt_id=62068
This is one of the earliest take-aparts of the BWR I am aware of: https://chestercycling.wordpress.com/2013/05/22/inside-the-brompton-wide-range-bwr-hub/
Here's a pictured step by step report of dealing with the internals (in German - Google-translate may help): http://www.bromptonauten.de/phorum3/read.php?1,36721,36721#msg-36721
Here's another one in English (did not look into it in detail): https://bromptoncraft.wordpress.com/2021/07/04/disassembling-the-brompton-bwr-hub/

 

[mitchibob]

In case you want to do it yourself:
Here's the parts scheme https://brommieplus.com/portal_b1_page.php?owner_num=b1_408821&button_num=b1&cnt_id=62068
This is one of the earliest take-aparts of the BWR I am aware of: https://chestercycling.wordpress.com/2013/05/22/inside-the-brompton-wide-range-bwr-hub/
Here's a pictured step by step report of dealing with the internals (in German - Google-translate may help): http://www.bromptonauten.de/phorum3/read.php?1,36721,36721#msg-36721
Here's another one in English (did not look into it in detail): https://bromptoncraft.wordpress.com/2021/07/04/disassembling-the-brompton-bwr-hub/

Oh yeah... I'm going to want to have a spare, fully working hub, before taking that on! And a well-lit workshop!

 

[rogerzilla]

The old UK hubs are easy (once you've persuaded the internals to unscrew from the shell). The N.I.G. gubbins makes newer ones more difficult.

The irony is that the easy ones don't generally need overhaul anyway, as they use total-loss lubrication.

 

[mitchibob]

The thing is, I need new rim anyway, and it's been over 30 years since I built a wheel myself, and again, need to sort out a workshop space (or a nice, secure shed, with a view up the valley, secure multi-bike hanging space, nice work-bench for a vice, and truing jig... a bit like the garage of a bike shop I worked in for work-experience, then for a bit of sub-minimal wage summer job, but trade price on kit, as learnt so much every week).

Probably good time to change gear and brake cables, though, or at least shorten now that I'm definitely preferring the switch to JK S-type bars on what is M stem, and while I don't mind too much the additional cable, I should tidy it up. Brake cables I should really replace though.

But always blown away with quality of responses on this forum. Learnt so much!