Sturmey Archer Hub Gear Problem

check_six

I'm having trouble with a three speed sturmey archer hub gear.

I can get the bike into the middle gear okay, but even when I disconnect the wee screw thread bit from the chain that goes into the hub to change the gears, it doesn't seem to change the gears.

I can't quite remember if loosening the cable should drop the bike into top gear (I think it does), but even when I'm putting tension on the cable, I don't seem to be able to get the other gear (bottom gear).

When I stop pushing the pedals around, they keep rotating under pressure from the chain like the freewheel isn't engaging properly.

Anyone any advice regarding sticky sturmey archer gear systems?

joxerjohn

Casting my mind back many years, loosening the cable or indeed unscrewing the barrell adjuster should put it in third i.e top gear. I sound like it is stuck in second and the I don't like the sound of the free wheel alos not working. I remember that you can also undo the nut where the gear shifter goes into the axel and remove the rod that the cable attaches to and clean it up.

If you still have problems then a visit to the LBS I think will be needed.

check_six

joxerjohn wrote: »

Casting my mind back many years, loosening the cable or indeed unscrewing the barrell adjuster should put it in third i.e top gear. I sound like it is stuck in second and the I don't like the sound of the free wheel alos not working. I remember that you can also undo the nut where the gear shifter goes into the axel and remove the rod that the cable attaches to and clean it up.

If you still have problems then a visit to the LBS I think will be needed.

Okay that sounds like a good starting point. I'll see if I can get at the rod.
Thank you.

Holyboy

Oh dear, you have opened a can of worms:p

Firstly is it an old hub or a new hub?

If it's old it may just need re-lubing which really means opening it up, cleaning and re-greasing the internals and my preference (if it doesn't have a hub brake) an oil bath too.

If that doesn't work or it seems well lubed when opened then it could be many other things like a bent axle(though it's very rare), a worn clutch spring or more than likely something has broken and left debris in there either bearings or cage, pawls or pawl springs being the most likely.

If it's a newer hub then the latter is usually the case.

Three speed hubs are not as complicated as some people think but opening your first one can be scary, if you do decide on doing it make sure you print out an exploded diagram from the Sturmey Archer website so you can see exactly how to get it back together.

piston

If it is one of the older AW3 oil bath type, I would fill it with diesel and let it sit for a day or so and drain it and put fresh oil into it and see if it works any better.

If this doesn't work, then time to open. There are any number of online guides, such as the one on Sheldon Brown's site and I think the Sturmey Archer site has service information for the older hubs. SJS cycles sell all the parts although it may be more cost effective just to buy another hub and just swap the internals into your wheel. Wash them in diesel first and bear in mind that the bearings in an AW3 hub should have a very slight amount of play (1/8" at the rim of a 26" wheel is generally recommended).

What oil you use is also important. Do not use 3 in 1 or anything similar as it gunges up and corrodes the internals. Ideally use an SAE 30 oil, often sold as lawnmower motor oil or otherwise use normal multigrade engine oil, preferabley not one of the modern fully senthetic ones.

check_six

Thank you for the top tips!

This is what I feared...

I didn't get a chance to have a look at the hub last night, and the bike may be home late tonight as well. I'm going to be able to get a bit of oil into it maybe and see how we go.

The hub itself is on a bike that is about seven years old and has AW written on the side of it. I'm thinking this would it indicate that it is the AW3 type hub mentioned above.

piston

Does it have an oil port? I suspect if it's only 7 years old, it is one of the grease type. The AW3 has been in production since about 1936.

If so, find an online service guide, open it and wash it out, check obvious damage/wear and pack with fresh grease (check what they recommend, I wouldn't use normal lithium grease in this) and try again. It could be the grease has hardened with age. It's why I think the oil bath method was better but they leaked (in the best tradition of British engineering) and people don't like that nowadays.

I don't know much about the more modern ones as I only tend to deal with pre-1960s bikes.

check_six

++Update+++ !

I got to work on the bike over the weekend. I got some oil into the hub through the slot for the connector chain. With the wheel off I was able to change between the three gears by pulling on the chain, so I decided to investigate the gear cable. I found that the blasted thing had metal heads/terminators (ferrules?) at both ends, so the cable could not be removed without cutting off the barrel adjuster bit. This barrel adjuster bit is the thing which allows the cable to join the connector chain that goes into the hub. Clearly the one on this bike was put on in the factory.

I needed something which would allow me to join an adjuster barrel to a regular gear cable. First shop I went to had no idea what I was talking about, the next sent me to Square Wheel who were able to provide the now near-mythical adjuster barrel which would connect to the cable. They warned me in the shop not to put too much torque on the nuts which connect the cable as they would fail pretty quickly if I did.

Everything works now with the new cable and the lubricated hub, but I need to finish the job properly with some fresh cable outer. The one on the bike (on closer inspection) is pretty worn out.

Thanks to all for your advice.