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Posts Tagged ‘coaster brake service’

I tend to pull old bike things apart in my spare moments, and while some might call it insanity, to me it’s therapy.

I find it amazing how something that seemed so useless when found can be so unexpectedly handy later on in time.

Vicki's speedwell with the modern wheels

Vicki’s speedwell with the modern wheels

Take for example Vicki’s old Speedwell wheels that she donated to me some time ago after upgrading to her Nexus 3 coaster. It’s worth referring to her blog  “Bicycles in Newcastle” ( on the above link ) about the issues she went through with it.

The rear wheel had a Renak model 60 – 40 hole hub with poor braking, and for some reason I thought of it when dismantling the horrendously rusty Favorit hub from the salvaged Apollo II.

can you believe the rust ?

the favorit – can you believe the rusty hub shell ?

The internals seemed very similar, but the brake shoes on the Favorit seemed much less worn. Could they be used to improve the Renak ? The shoes on the Favorit measured slightly larger in diameter than the Renak’s and the other mating parts looked very similar.

the outer bearings always cop it - outside end of the driver

the outer bearings always cop it – outside end of the driver

the spring clip comes off to release the rollers and driver

the spring clip comes off to release the rollers and driver ring

the driver, with needle rollers

the driver, with roller bearings

favorit (L) & renak (R)

note the wear – favorit (L) & renak (R) interlocking brake shoes

The Favorit is a 36H from a later 27″ wheel, but of course this is irrelevant to the internal compatability – if it works, it works !

Dismantling and cleaning these hubs is easy work apart from some stubborn grease in various crevices like those of the ball bearing cages – I use kerosene and a toothbrush and rags, and also a brass wire brush for the axle threads etc.

the internals

some of the internals

and the rest

and the rest

Upon reassembly with plenty of fresh grease everywhere, the hub seems to be working but there’s no real way to tell what the brakes are like until fitting it to the rim, to a bike, and riding it. I don’t have a use for this hub/wheel yet, but I’m sure one will eventuate !

These old hubs use track cogs and a left hand threaded lockring – the cogs are still available in plenty of sizes thanks to the fixed gear craze …

not bad, hey ?

not bad, hey ?

brake arm end

brake arm end

Tip – use a penetrating catalyst like PB Blaster on both ends of the nipples before attempting rusty spoke removal. The steel eyelet washers were almost corroded right away, probably from electrolytic reaction with the brass nipples.

As you can see, you can make old hubs really clean and shiny when they’re out of the wheel and clear of all the spokes – the same with rims too.

with a mavic 700C road rim for comparison

with an old mavic 700C road rim for comparison

The painted steel rims are in reasonable structural condition and may be recycled – well, they will need to be if this hub works, as the rear is the only spare 40 hole rim I have !

If the coaster brake doesn’t work sufficiently there’s not much point re-doing the front wheel as these painted rims aren’t really suited to calliper brakes.

the cog will need to be removed again for re-spoking

the cog will need to be removed again for re-spoking

I will need to find a 32H hub if I’m to get the matching front wheel going again, as the front hub internals were used by the bike shop to fit Vicki’s new 700C wheels to the Speedwell.

But that’s for another day …

uh-oh !

uh-oh !

Here’s one I came across today on my ride, but :

a)  it’s total crap, and

b)  who knows, the owner might actually come back for it …

A good recyclist is an honest recyclist —- Karma !

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This is the rear wheel from my Jack Walsh step through – and while coaster hubs are all very similar inside, different brands are not exactly the same. The more of these I overhaul, the quicker and easier they become, and this one seems quite well designed. This hub should also be a sharp stopper, as it’s a Japanese ’80s (?) model. It has three smaller brake shoes unlike some other types that have only two larger ones.

what’s inside … minus the cog dust cover, splined cog and spring – that fit to the drive screw

Here’s  the exploded view, and while the hub disassembles further, I will leave it as is and force clean and grease the brake arm side bearings in situ to save some time – perhaps not best practice, but this hub was quite clean inside. As usual the little outside driver bearing was the driest, with the inner races still being reasonably greasy.

I’m not sure whether teflon grease is the best option for a brake hub, but it seemed OK on previous hubs I’ve done. This grease was purchased at an auto store as you get more for less than at the bike shops, I’m sorry to say.

stuck like glue … then grease over the top

The small shoes stuck to the grease on the expander wedge, then I greased over them and also all over the inner hub surfaces. This made for an easy re-assembly, pushing in from underneath the brake arm side while holding the shoes with one hand, after which the driver screw goes in from the drive side to mate with the screw thread inside the expander drum.

inserting the drive screw

After that, the little outer axle bearing and its cone and locknut go on the drive side axle, followed by a dust cover ring, the splined cog and its snap ring and you’re done – bar the cone adjustment – and that may need re-doing after fitting to the bike and/or riding.

the drive side cone with lock nut adjusts wheel play

Next job is to true the wheel and tighten the loose spokes…

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loosening the locknut and cone after removing the sprocket shows some rust on the bearing cages

These common “Falcon” brand coaster hubs have a tendency to let in water if left out in the rain, and as I am thinking of using a spare pair of salvaged 16″ wheels for a home made bike trailer, I decided to overhaul them just in case.

The steel rim had to be de-rusted on the inside then the hub disassembled, cleaned and re-greased. There is a good description of this process on the useful Park Tools site  – suffice to say the most difficult part is reassembly as your hands quickly become covered in slippery grease if you get it wrong, and that makes it really hard to then hold the assembly  together …

The brake arm, shoes, clutch and spring will only fit into the left side of this hub when held together as an assembly.

When the assembly is pushed home the spiral-threaded driver can then be screwed into the clutch from the right hand side of the hub, then the outer bearing, cone and locknut fitted.

water has entered via the driver & its cone

Coaster brakes use this spiral threaded driver to engage with the spiral inner of a notched clutch – when pedalling forward the clutch wedges onto the inner hub to allow forward drive. When pedalling back the driver disengages then wedges the clutch into the brake shoes which expand out and slow the hub by friction. A return spring releases them again as back pedal pressure is eased – simple really ! Not so simple though are the internally geared coaster hubs ….

the parts - still in the old grease

In my experience the first bearings to go dry are the small ring on the outside of the driver as they are most vulnerable to water, and the grease is washed out causing rust and pitting. Water can also flow through the driver down the axle to eventually rust the springs on the brake arm side. This was just starting to happen on this example.

The obvious lesson is that bikes really suffer if regularly left out in the weather, and then maintenance needs to be greatly increased to compensate if the bike is not to become a problem.

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