Hub gears and drum brakes

[Trigger]

I'm very tempted to dump all the dearailleurs and rim brakes from my commuter bike and make it more weather friendly for winter. I was thinking IHG drum brake combo rear and a drum brake dynamo combo front.

My initial reservations are:

I'm completely clueless about hub gears and drum brakes, I've never even ridden a bike with either never mind tinkered with them, they look complex and my reading comprehension is crap, whenever I try to read up about them I just start to glaze over.

I ride when it's icy and snowy, I know we don't always get it but at the minute all I need to do if we get snow is to quickly swap both wheels for my other cheap set wearing Marathon Winters, this wont be an option when tied into IHG/drum brakes/dynamo.

Punctures. I had a quick look on how to remove the rear wheel for a puncture for a hub gear alone and it looked a nightmare, combined with the drum brake I'm not sure I'd be too enamoured with the thought of trying to do that at the side of the road on a wet January morning/evening.

Any thoughts? Part of me wants to do it just to give the experience of fiddling with components I've never used before, but the other part of me is saying leave it alone and just carry on as you are with this bike.

[thirdcrank]

You may find that one of your problems is sourcing these parts loose, rather than in complete bikes. I say this from experience, although not recent. With the exception of a few specialist shops, the UK bike trade is not geared-up for drum brakes and gears.

You are right to be concerned about getting back wheels out, especially if you don't rate yourself as a mechanic. In my limited experience (one of each make) I've found a Sachs AKA SRAM drum brake with 7 speed hub much easier to remove and refit than a Shimano Nexus 7 with a coaster brake. Not everybody agrees, but I don't think drum brakes are as good as decent rim brakes. I've no experience of discs.

[[XAP]Bob]

For punctures use a linear tube, then replace the origimal in the warm at home.

[Hein]

Roadside patch of the rear tube is easily done without removing the wheel. Pull the tyre from the rim at the non-drive-side and pull the tube out. You now have a tube that is running around the LH seat- and chainstay but is otherwise free, while the tyre is still on the rim with its RH side. Find the hole, patch it, reassemble (try to find the piece of glass or whatever punctured your tyre before reassembly).

The trickiest part is to find the hole. Maybe you can feel the air coming out of it, maybe not (in most cases, you can when pumping up the tube moderately, but probably not in winter with cold hands and cold cheeks). You can pour your drink into your hat and run the tube through it, watching for bubbles. Or variations of that.

In case that fails, dis- and reassembly of an IGH wheel is not too difficult. Do it a few times and it becomes routine. Disengage the brake and shift cables, loosen the torque arm, loosen the axle nuts. Reassembly in reverse order, followed by a quick adjustment of brake and shifting cable if necessary. Brake is probably obvious. Shifting adjustment is dependent on the hub but pretty straightforward in most cases (e.g. align one thing with the other in a certain gear).

[mjr]

I'm partly with Trigger - see the thread viewtopic.php?f=5&t=84794 where various kind souls explained a few bits about hubs to me - but I've ridden a 1x6 derailleur bike a few times recently and as a result I think that a 3-speed hub (maybe 42", 57" and 72") would work around town and a 5-speed hub (adding something in the low 30s and a high speed up near 90") would probably work well for the open road.

I don't think punctures would always be too bad because I repaired a puncture on a derailleur bike without removing the rear wheel as Hein describes, partly to see if I could and partly because the back wheel is a fairly tight fit in its beat-up steel stays. The repair's worked fine for a few months so far.

The tyre/wheel swapping idea I don't know how to solve, although rather than swap wheels even now we keep a fat tyred bike with more wintery tyres on.

What puts me off converting is the messy issues of dropouts. As I understand it, hub-geared bikes use more horizontal dropouts as a way to fine-tune the chain tension. My main bike's got very vertical dropouts, as far as I can see. I could reuse the derailleur as a tensioner but then the chain's still down near the ground and probably collecting the junk kicked up off the road that hub gear chains usually avoid. So I think hub gears may be something for the next bike...

[robc02]

What puts me off converting is the messy issues of dropouts. As I understand it, hub-geared bikes use more horizontal dropouts as a way to fine-tune the chain tension. My main bike's got very vertical dropouts, as far as I can see. I could reuse the derailleur as a tensioner but then the chain's still down near the ground and probably collecting the junk kicked up off the road that hub gear chains usually avoid.

A chain tensioner like this or this would avoid the problem you describe. You just make sure you have the shortest chain possible and the tensioner takes up the small amount of slack - the push up type keeps it further out of the way of road debris than the pull down type.

Sturmey Archer 3 speed with drum and drum front hubs appear on ebay fairly regularly. This could be a good way to acquire hubs for a spare pair of wheels at modest price (or even both pairs). Less frequently dynamo / drums appear as well.

[barrym]

Are chain pensioners really necessary? If you use a half link join or a complete half link chain surely you can get to within 1/2 inch chain length which I would have thought would stayed where it should.

[breakwellmz]

You would think so wouldn`t you?
But it never seems to quite work out right-either too tight or too loose..

[Brucey]

if you have VDOs then a tensioner is not the end of the world.

For a town bike an aluminium SA 3-speed (or a steel one built with spoke washers, it is about the same weight) is a sensible choice.

With SA hubs (rim brakes) you need to worry about

1) the track nuts
2) the toggle chain
3) the NTWs.

External NTWs are easier to deal with than the internal type IMV. The toggle chain takes seconds to deal with.

If you have a hub brake as well then you need to deal with;

4) the brake cable (it just unhooks, no tools required)

5) the reaction arm (one bolt at the rear, no tools required at the front)

The thing that really slows down the removal of the rear wheel is a chaincase, if you have one fitted.

So if you have a chaincase an endless tube is a good solution at the rear. I just patch them in situ (which works fine) but if I was routinely pushed for time I might carry an aerosol repair kit so that I could complete my journey with minimal delay.

cheers

[Trigger]

Thanks, some great replies.

I'm confident enough of a mechanic and have built plenty of bikes, I've just no experience of these parts.

I was thinking of maybe a SA 5 speed as it's quite hilly around here and I also do some other longer rides on this bike other than just commuting, nothing serious though but it would be nice to have a couple more than 3sp.

How much of a difference would I notice going from V brakes to drums? And does the size of the rear drum make much difference?

The other thing that had me thinking was the plethora of ancillary little parts that you need for these sort of conversions, packs of fittings or other such things that I've maybe overlooked.

What about chainset, does it need to be anything special to accommodate this lot or will any old single chain ring set up work?

[Brucey]

the hubs (if you buy SA ones new) will come with all the fittings you need for installation including cables. However if your frame has unusually fat forks or chainstays then you may need to buy larger reaction arm clips (they are not expensive).

You can run hub brakes from V brake levers but they won't be that powerful; you need shorter pull levers really.

V brakes are more powerful in the dry and probably modulate better than hub brakes too. However in the wet hub brakes are usually unaffected which is very welcome. In any event with both brakes working normally you can pull up pretty quickly. Because the rear brake is on a long cable it never works quite as well as the front. On most of the sit-up and beg bikes I've ridden with hub brakes they are 'panic proof' in the dry, anyway; you can pull on both levers in a panic stricken fashion and all that happens is that you stop. With many such setups here appears to be no real risk of locking the rear or the front. Obviously things are going to be different with a more frontward weight distribution, but even with just 70mm brakes my utility bike will pull up from 20mph in about 4m when it needs to.

However hub brakes can take a long time to bed in fully, so don't expect miracles out of the box.

The rear brake can do more work on a utility bike (more rear loading) so whilst a 90mm rear brake might be wasted on a bike with drops and no rear load, on a utility bike it might carry the brunt of normal braking. If you regularly carry a heavy load then a 90mm front brake is a good idea. A 70mm brake can give enough power but it will certainly need to be bedded in well and will benefit from a slight modification to allow better force distribution internally too.

Hub brakes are not perfect by any means; you can get squealing (although I never have) and if any water does get in the brake (e.g. if the bike is leant over and it rains overnight) then the brake can stick on slightly until the linings dry out.

Although the linings will last several years at least (five years of daily GPO use was the original spec), some folk say that the 2001-on linings from Taiwan don't last as long. I don't know about this; what I do know is that once every year or two it would be a good idea to take the brake plate off and clean the dust out, put a smear of grease on the cams etc.

The most common fault with neglected hub brakes is that the shaft through the brake plate seizes up. If this doesn't happen then they can go on for many years with no attention whatsoever.

cheers

[mjr]

Thanks Brucey. Are coaster brakes basically drum brakes controlled by backpedaling? Would that avoid the long cable problem? I've used them on German hire bikes and quite liked them. Any problems with chain tensioners or other conversion aspects?

[Brucey]

IMHO the long cable isn't a problem, it is a benefit; without it I am sure that you would lock the rear brake more easily!

Coaster brakes are metal-on-metal brakes which are lubricated with grease; the same grease as the hub internals use. If this sounds like the hub internals wind up swimming in bits of worn brake lining, appearances would not be deceptive....

As a brake, coaster brakes are normally quite reliable, and have the advantage that there is no cable to go wrong or anything. However there is usually a tiny piece of pressed steel or brass inside that make the brake work on most single speed designs. When this goes wrong the rear wheel locks up instantly (whether you are using the brake or not) and you can't ride the bike any more.

As brakes go I think they are least able to withstand heavy use downhill (when they get very hot the grease comes out, hence the name of the 'Repack Run' in Marin County) and they can have very poor modulation, especially if you are not used to them. It is very easy to lock the rear wheel with most brakes of this kind that I have tried, and you can't do all kinds of quite normal things like backpedal half a turn when stopped to set the pedals in the right place to start again.

If you subject a coaster brake with no grease in it to heavy use, it will quite likely modulate poorly if not seize up completely.

In quite a few (allegedly civilised) countries it is perfectly legal and normal to sell a bike with just one brake and for that brake to be a coaster brake. In an emergency you will take x2 or x3 longer to stop with a rear brake only, and there is always a chance that the one brake could fail, leaving you with nothing. Just one brake is not a good idea, IMHO.

I have noticed that some German-spec bikes come fitted with two ordinary brakes and in addition they also have a third coaster brake. I guess you can use whichever ones you prefer.

All coaster brakes have a drag spring inside them which makes for a tiny reduction in your speed, all the time. If you have an IGH with a coaster brake and you don't want the brake, it is usually possible for the brake linings to be removed, and the hub then to work as normal. However you will most likely need to retain the reaction arm because that allows the LH hub bearing to work correctly. A coaster brake adds about 1/2 - 3/4lb to a hub.

Shimano Roller brakes are very similar to coaster brakes but are cable operated, need greasing more often, and the wear debris doesn't get into the hub innards so easily. They have many other similar characteristics to coaster brakes, but are (if anything) slightly heavier.

You can't run a coaster brake with a normal chain tensioner; the chain tension is very high on the lower run when the brake is used and this will just tear a standard tensioner apart.

cheers

[Trigger]

Excellent knowledge as always, Brucey

I was thinking about it last night and I came to the conclusion that a 3sp would be enough, is there a big difference between the steel bodied ones and the alu?

A couple of things that are still baffling me:

Why are all the SA OLNs so far away from modern frame standards, and is it just a case of using some spacers?

All the talk of chain line with various wheel dish/sprocket width permutations is confusing.

Cable runs: can I use existing cable stops or do I need a variety of band on types to switch from derailluers/rim brakes to IHG/drum brakes.

Thanks again, learning lots.

[[XAP]Bob]

Just use spacers as needed - the axles are long enough, but why make the hub wider than originally designed - no-one uses these newfangled wide mouthed frames