Shimano Roller Brakes

[Mick F]

How do they work?
Why do you have to grease them?
and how often?

There's a grease port on the side of the unit, I read stuff about the brake when I bought it, but have mislaid the instructions.
Any advice about maintenance will be gratefully received from other rollerbrake users please.

The Shimano website isn't to user friendly these days, they seem to have changed it for the worst. Perhaps they know I'm a Campag fan.

[workhard]

How do they work?

I guessing friction and heat are involved somewhere in the piece. It's a drum brake basically.

Why do you have to grease them?

Because that nice Mr Shimano has politely asked you to and if you don't they will make a truly awful horrendous noise when you try to stop.

and how often?

once a year iirc or when they get noisy.

CJ once told me they were no good on tour, cos if you ride with them on down a long hill they get very hot, fade, the grease leaks or boils and they will then be very noisy.

Guess what? CJ was right and I was wrong. But experience is a great teacher.

However the chap I sold the bike to was very happy with it. Trek ATB with a Nexus 7 spead hub and rollers front and rear with a nexus dynohub. Used it to commute from Clapham Junction to Brixton every day for about two years.

[Mick F]

Thanks for that, somehow I knew all the answers anyway! I was hoping for someone who'd used them for a while. Although I've had this hub and brake for some years, it was only on a shopping/utility bike that probably hasn't done much more than 100 miles in its life.

It's gonna get some use now!

As for fading, I seem to have the opposite problem. I came down a long hill this afternoon at something more than 30mph and had to brake as I approached the traffic lights. The hill is steep and long - maybe some people know it? Gunnislake Hill, notorious on the E2E route - I dabbed the brakes as I came hurtling down, normally I just let the bike fly, but today there was quite a blustery cross-wind. The brake didn't fade at all, it gripped tighter all of a sudden!

Yesterday, I tried a very steep hill and kept stopping hard to test it out. Yes, it was hot and smelly afterwards!

Grease seems a strange thing to shove into a brake. But if that's what's needed, who am I to say not? They must be some SORT of drum brake, but not in the conventional sense. They have some sort of cam and bearings in there and there's no friction material to rub away but I know nothing more than that. They don't seem to pull apart to see inside.

They must be made of Japanese Magic Stuff.

[thirdcrank]

... The Shimano website isn't to user friendly these days,..

It doesn't seem to have changed at all to me.

http://techdocs.shimano.com/techdocs/index.jsp

Scroll down to "Comfort" then all the various instruction leaflets are listed as pdf downloads. (Brakes are under ..... "brakes"... )

[cycleruk]

From Wikipedia:-
"A roller brake is a modular cable-operated drum brake for use on specially splined front and rear hubs. Unlike a traditional drum brake, the Roller Brake can be easily removed from the hub. It also contains a torque-limiting device called a power modulator designed to make it difficult to skid the wheel. In practice this can reduce its effectiveness on bicycles with adult-sized wheels."

But as yours is child size wheel you should have no problems.

Sort of offpost but worth a look:- http://en.wikipedia.org/wiki/Bicycle_brake_systems

P.S. Nice job on the Chopper wheel.

[MikewsMITH2]

Shimano say:
The front Inter-M brake system should only be
installed to the left side of a bicycle which is 26" or
larger. If it is used on a bicycle which is smaller than
26", the braking force may be too great, which could
cause accidents.

Mick F said
The brake didn't fade at all, it gripped tighter all of a sudden!
Yesterday, I tried a very steep hill and kept stopping hard to test it out. Yes, it was hot and smelly afterwards!

see safety warnings below:

When using the Shimano Inter-M brake system,
avoid continuous application of the brakes when
riding down long slopes, as this will cause the
internal brake parts to become very hot, and this may
weaken braking performance. It may also cause a
reduction in the amount of brake grease inside the
brake, and this can lead to problems such as
abnormally sudden braking.

How heavy is your rig?

These standards specify the
performance for an overall weight of 100 kg. If the
overall weight exceeds 100 kg, the braking force
provided by the system may be insufficient for
correct braking, and durability of the system may system may
also be reduced.

Ooo..Err! Have look at ebay item number 120532804314

[Mick F]

... The Shimano website isn't to user friendly these days,..

It doesn't seem to have changed at all to me.http://techdocs.shimano.com/techdocs/index.jsp
Scroll down to "Comfort" then all the various instruction leaflets are listed as pdf downloads. (Brakes are under ..... "brakes"... )

When did you last look?
I last looked in 2006 or 7.

Sort of offpost but worth a look:- http://en.wikipedia.org/wiki/Bicycle_brake_systems
But as yours is child size wheel you should have no problems.
P.S. Nice job on the Chopper wheel.

Thanks!
and yes, I've looked at Wiki .....

Shimano say:
The front Inter-M brake system should only be
installed to the left side of a bicycle which is 26" or
larger. If it is used on a bicycle which is smaller than
26", the braking force may be too great, which could
cause accidents.

see safety warnings below:

When using the Shimano Inter-M brake system,
avoid continuous application of the brakes when
riding down long slopes, as this will cause the
internal brake parts to become very hot, and this may
weaken braking performance. It may also cause a
reduction in the amount of brake grease inside the
brake, and this can lead to problems such as
abnormally sudden braking.

How heavy is your rig?

44lbs for the Chopper, 185lbs for me, and Gordon only knows how much luggage.

These standards specify the
performance for an overall weight of 100 kg. If the
overall weight exceeds 100 kg, the braking force
provided by the system may be insufficient for
correct braking, and durability of the system may system may
also be reduced.

100kg = 220lbs or thereabouts, so I'm well above the limit for one roller brake. I still have a rear brake as well.

Ooo..Err! Have look at ebay item number 120532804314

Fancy it?
I may, but it needs another wheel-build and new spokes!


I'll stick with what I've got, and I'll keep everybody informed as I go.

[mill4six]

I don't have any grease, I use the heaviest oil I can get very irregularly, since the kids knocked the can over I've used ordinary 3 in 1 which doesn't work for long, in fact it needs doing again as it gets noisy and snatchy when it's dry.

[niggle]

My Subway 8 commuter has them front and rear (the BRM70 version). The Subway must have done over 3000 miles over the last three years or so commuting in Cornwall in all weathers and I have never greased them or had to do anything else once the cables had been adjusted after a couple of hundred miles. In my humble opinion they are completely and utterly brilliant for commuting purposes: no pad wear, no rim wear, unaffected by weather or road muck and virtually no maintenance.

I bought some of the special grease the other month and read on the instructions that it should be used if the brakes become harsh or noisy: still waiting for that to happen.... Sounds like your one does need some, judging by the instructions its a pretty simple procedure so I would give it a go if I were you.

EDIT: found a picture:

[Mick F]

Thanks!
All becoming clearer now.
I'll drizzle some thick oil in the hole later. It still seems counter-intuitive to oil a brake!

[niggle]

Thanks!
All becoming clearer now.
I'll drizzle some thick oil in the hole later. It still seems counter-intuitive to oil a brake!

I suppose thick oil will work but maybe it wont last as long as grease? Instructions on the tube say to squeeze the grease in a little at a time whilst turning the wheel.

HTH

[niggle]

Just to add that they are good brakes and you can modulate the your braking with them quite well, but there is an inbuilt power modulator on the front one at least which makes impossible to lock the wheel up, but reduces the stopping power available below what a competent rider could get from a good tyre IMO. Recently I rode down an extremely steep section of surfaced path (something like 1:3 I reckon on the Great Flat Lode trail near Camborne, going down to Brea village) I avoided careering down the hill and managed to stop at the bottom, but it was touch and go.

[Mick F]

Yes, it has a Power Modulator - Sheldon Brown was scathing about them - but I think it's a good idea. I'd hate to lock up the front wheel.

I wonder if it's a sort of ABS for bikes - it can only be a good thing.

I must have a test to see if I can lock up, but perhaps it only works with rapid deceleration rather than just a slipping clutch arrangement.

[workhard]

In my humble opinion they are completely and utterly brilliant for commuting purposes: no pad wear, no rim wear, unaffected by weather or road muck and virtually no maintenance.

hear, hear.

butt ugly though. although the new ones do have a funkier cooling disc.

[Mick F]

PS.
Just thought, I'd better describe the Power Modulator for Shimano Roller Brakes.

The roller brake on the front is exactly the same for the rear but the rear has a different stabiliser arm. Neither of the brakes has a Power Modulator, it's the front hub that houses it. The roller brakes are fitted onto the hubs and engage with a castellated affair and is held on by a lock-nut on the axle.

The Power Modulator is inside the front hub and seems to occupy a "bulge" inside. I suppose that if the front roller brake locks up, the Power Modulator must "slip" in some way to relieve the situation. Maybe it's a VERY strong spring on a clutch but I think it has to be more sophisticated than that.

You can see the bulge on the hub.

Has anyone ever stripped one down?