Roller brakes: running friction?
 

Shimano says the following about their roller brakes: "Inter-M brake is
different from conventional brakes in that the inside of the brake drum
is filled with grease. This may cause the turning of the wheel to be
slightly heavier than usual, particularly in cold weather"

1. So they have running friction. Does anybody know anything more about
this?

2. They say that there should be 15 mm of play in the brake lever. That
is a lot of movement. Perhaps the gap between pad and drum needs to be
large to reduce the drag caused by the grease in the gap. Is that the
reason?

Roller brakes: running friction?
 

Roller brakes: running friction?
 

I wrote:
wrote:
2. They say that there should be 15 mm of play in the brake lever.
That is a lot of movement. Perhaps the gap between pad and drum needs
to be large to reduce the drag caused by the grease in the gap. Is
that the reason?

I suppose so, but the play is only apparent when rocking a stopped
bike back and forth with the brake on. You don't notice it when
braking normally.

Sorry, I misunderstood what "play" you were referring to (there is some
fore & aft play too). I would what Shimano are talking about: "lever
travel".

That is a lot of movement. Perhaps the gap between pad and drum needs
to be large to reduce the drag caused by the grease in the gap. Is
that the reason?

Yes indeed.

Don't expect it to be a powerful brake! Advantages, though: reduced
cleaning and maintenance, zero rim wear, no need to have rim perfectly
true.

~PB

Roller brakes: running friction?
 

Roller brakes: running friction?
 

Thanks for the replies. By 'play' I meant 'lever travel'. More quotes
from Shimano:

"Turn the cable adjusting bolt of the brake unit or brake lever so that
there is about 15 mm of play in the brake lever."

"The amount of movement in the inner cable must be 14.5 mm or more when
the brake lever is depressed. If it is less than 14.5 mm, braking
performance will suffer, and the brakes may fail to work."

Perhaps that last sentence indicates that:
friction - heat - reduced performance


"If you apply the front Inter-M brake strongly while the bicycle is
stopped and then shake the wheel, you will notice that there is a small
amount of play in the brakes. This is normal, and will not cause any
problems at all while riding."


"The front Inter-M brake has a built-in power modulator which controls
the braking force applied to the hub. Noise is generated by the
operation of the power modulator when the brake is applied, but this is
not a sign of a malfunction."

Curiouser and curiouser.

Roller brakes: running friction?
 

In article ,
says...

As another poster observes, you don't get disc brake standard instant
stopping with hub brakes but it is more than perfectly adequate.

Adquate for what? I have a Nexus 7 and I can grab the brake till it touches
the bar and it only slows the bike down a bit. An adequate brake should be
able to lock up the wheel. If my bike had cantilever studs I would have gotten
rid of this brake. Especially since I just found out the brake weighs over
a pound.
-----------------
Alex

Roller brakes: running friction?
 

Alex Rodriguez wrote:
An adequate brake should be able to lock up the wheel.

Shimano says that the power modulator (a clutch) in the brake "prevents
the wheel from locking-up if the brake force is getting too strong."

See their picture at:
http://cycle.shimano-eu.com/publish/...the_power.html

Roller brakes: running friction?
 

In uk.rec.cycling Alex Rodriguez wrote:
In article ,
says...

As another poster observes, you don't get disc brake standard instant
stopping with hub brakes but it is more than perfectly adequate.

Adquate for what? I have a Nexus 7 and I can grab the brake till it touches
the bar and it only slows the bike down a bit. An adequate brake should be
able to lock up the wheel. If my bike had cantilever studs I would have gotten
rid of this brake. Especially since I just found out the brake weighs over
a pound.

i am looking at a ridgeback switch at the moment.
i was trying to get one with disk brakes but they're out of stock.
the guy in the shop said hub brakes are better anyway.

are you saying this isn't true?

what about hub gears (nexus 8) vs regular derailleurs (shimano deore)?

Roller brakes: running friction?
 

"Alex Rodriguez" wrote in message
...

Adquate for what? I have a Nexus 7 and I can grab the brake till it
touches
the bar and it only slows the bike down a bit. An adequate brake should
be
able to lock up the wheel.

Apply the front brake sufficiently and it will be able to :-)

Seriously, the back brake shouldn't be doing much of the slowing anyway, so
being a bit crap isn't much of a problem. Unless the front brake is also
crap.

(This does not apply to tandems :-) )

cheers,
clive

Roller brakes: running friction?
 

Clive George wrote:
"Alex Rodriguez" wrote in message
...

Adquate for what? I have a Nexus 7 and I can grab the brake till it
touches
the bar and it only slows the bike down a bit. An adequate brake
should be
able to lock up the wheel.

Apply the front brake sufficiently and it will be able to :-)

Seriously, the back brake shouldn't be doing much of the slowing
anyway, so being a bit crap isn't much of a problem.

Agreed.

Unless the front brake is also crap.

Roller brakes can be used up front as well. It's one way to make you ride
extremely carefully, I suppose ;-)

~PB