drum brakes on non-drum designed hubs

[meb]

Can I take a drum brake and mount the rotor on a non drum hub to some
plates inside the flanges and spokes and secure plates through the
spokes and flanges via bolts? Seems it might put some stresses on
spokes in directions they were not designed to handle so might bend.
Anyone tried this and had success or failure?
Anyone think it would work/fail?
If so why/why not?


--
meb

[Hank Wirtz]

meb > wrote in
:

>
> Can I take a drum brake and mount the rotor on a non drum hub to some
> plates inside the flanges and spokes and secure plates through the
> spokes and flanges via bolts? Seems it might put some stresses on
> spokes in directions they were not designed to handle so might bend.
> Anyone tried this and had success or failure?
> Anyone think it would work/fail?
> If so why/why not?
>
>

Well, drum brakes work by pushing pads against the inside of the hub shell,
so no, that wouldn't work. But you're description is that of disc brakes.

And no, if you tried to attach the rotor straight to the spokes, you would
be forcing the wheel out of dish, if not out of true, with every
application of the brakes.

And to anticipate the unasked half of this question, no, it's generally not
a good idea to mount disc brakes on a frame or fork not designed for them.

[meb]

Hank Wirtz Wrote:
> meb > wrote in
> :
>
> >
> > Can I take a drum brake and mount the rotor on a non drum hub to
> some
> > plates inside the flanges and spokes and secure plates through the
> > spokes and flanges via bolts? Seems it might put some stresses on
> > spokes in directions they were not designed to handle so might bend.
> > Anyone tried this and had success or failure?
> > Anyone think it would work/fail?
> > If so why/why not?
> >
> >
>
> Well, drum brakes work by pushing pads against the inside of the hub
> shell,
> so no, that wouldn't work. But you're description is that of disc
> brakes.
>
> And no, if you tried to attach the rotor straight to the spokes, you
> would
> be forcing the wheel out of dish, if not out of true, with every
> application of the brakes.
>
> And to anticipate the unasked half of this question, no, it's generally
> not
> a good idea to mount disc brakes on a frame or fork not designed for
> them.

I meant drum-I mispoke when I called it a rotor.

Your answer on the spokes was fortunately directed at the issue I was
concerned about.

Thanks


--
meb

[Nate Knutson]

meb wrote:
> Hank Wirtz Wrote:
> > meb > wrote in
> > :
> >
> > >
> > > Can I take a drum brake and mount the rotor on a non drum hub to
> > some
> > > plates inside the flanges and spokes and secure plates through the
> > > spokes and flanges via bolts? Seems it might put some stresses on
> > > spokes in directions they were not designed to handle so might bend.
> > > Anyone tried this and had success or failure?
> > > Anyone think it would work/fail?
> > > If so why/why not?
> > >
> > >
> >
> > Well, drum brakes work by pushing pads against the inside of the hub
> > shell,
> > so no, that wouldn't work. But you're description is that of disc
> > brakes.
> >
> > And no, if you tried to attach the rotor straight to the spokes, you
> > would
> > be forcing the wheel out of dish, if not out of true, with every
> > application of the brakes.
> >
> > And to anticipate the unasked half of this question, no, it's generally
> > not
> > a good idea to mount disc brakes on a frame or fork not designed for
> > them.
>
> I meant drum-I mispoke when I called it a rotor.
>
> Your answer on the spokes was fortunately directed at the issue I was
> concerned about.
>
> Thanks
>
>
> --
> meb

One thing perhaps worth pointing out - one of the eletric-assist
retrofit kits out there has a rear rack mounted motor that rotates a
big plastic disc attached somehow on the left side of the rear wheel,
and the force is transmitted by the big plastic disc pressing on a
handful of spokes, like 3 or 4. I think the contact point is around
mid-span but I'm not sure - I only saw one of these in person once and
it was a while ago. The design struck me as really sketchy and
ill-conceived, but perhaps I'm missing something and the spokes don't
particularly mind this treatment. It was a bit like what I think you're
describing, with the spokes being pushed on oddly to deliver a
torsional load to the hub.

[Adam Rush]

Don't forget the mopeds of the 30's and 40's:

http://www.geocities.com/motorcity/garage/2136/

I would assume that one of those would be placing a much higher load on
the spokes than an electric retrofit.

[JeffWills]

meb wrote:
> > > Can I take a drum brake and mount the rotor on a non drum hub to
> > some
> > > plates inside the flanges and spokes and secure plates through the
>
> I meant drum-I mispoke when I called it a rotor.
>
> Your answer on the spokes was fortunately directed at the issue I was
> concerned about.
>

There are very few drum brakes which are separate from the hub. I'm
only aware of one, the Arai:
http://harriscyclery.net/page.cfm?PageID=49&action=details&sku=BR5001
This attaches to a rear hub which has threads on the left side.

My feeling is that you *could* mount it as you suggest, but it would be
extremely difficult to get the clearance between the pads and the drums
adjusted properly. This has to be very small so that there's very
little slack in the cable- otherwise, you run out of lever travel
before you get all your braking power.

You could attach one of these to a rear freewheel (threaded) hub and
use it on the front, but there's a bunch of additional considerations.
I've seen it done, and it ain't straightforward.

Jeff

[Nate Knutson]

JeffWills wrote:
> meb wrote:
> > > > Can I take a drum brake and mount the rotor on a non drum hub to
> > > some
> > > > plates inside the flanges and spokes and secure plates through the
> >
> > I meant drum-I mispoke when I called it a rotor.
> >
> > Your answer on the spokes was fortunately directed at the issue I was
> > concerned about.
> >
>
> There are very few drum brakes which are separate from the hub. I'm
> only aware of one, the Arai:
> http://harriscyclery.net/page.cfm?PageID=49&action=details&sku=BR5001
> This attaches to a rear hub which has threads on the left side.
>
> My feeling is that you *could* mount it as you suggest, but it would be
> extremely difficult to get the clearance between the pads and the drums
> adjusted properly. This has to be very small so that there's very
> little slack in the cable- otherwise, you run out of lever travel
> before you get all your braking power.
>
> You could attach one of these to a rear freewheel (threaded) hub and
> use it on the front, but there's a bunch of additional considerations.
> I've seen it done, and it ain't straightforward.
>
> Jeff

Any information about how well this worked once it was set up? (I
assume they had it set up with a normal brake lever as opposed to using
it as a drag brake?)

[A Muzi]

-snip-
> JeffWills wrote:
>>There are very few drum brakes which are separate from the hub. I'm
>>only aware of one, the Arai:
>>http://harriscyclery.net/page.cfm?PageID=49&action=details&sku=BR5001
>>This attaches to a rear hub which has threads on the left side.
>>My feeling is that you *could* mount it as you suggest, but it would be
>>extremely difficult to get the clearance between the pads and the drums
>>adjus ted properly. This has to be very small so that there's very
>>little slack in the cable- otherwise, you run out of lever travel
>>before you get all your braking power.
>>You could attach one of these to a rear freewheel (threaded) hub and
>>use it on the front, but there's a bunch of additional considerations.
>>I've seen it done, and it ain't straightforward.

Nate Knutson wrote:
> Any information about how well this worked once it was set up? (I
> assume they had it set up with a normal brake lever as opposed to using
> it as a drag brake?)

They are or were the standard tandem drag brake for years.
SImple effective cheap . Yes compatible with standard ( not
'linear' ) levers.

You would have to widen the fork and get a longer axle to
make this go - very one-off.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

[jtaylor]

"A Muzi" > wrote in message
...

> >>You could attach one of these to a rear freewheel (threaded) hub and
> >>use it on the front, but there's a bunch of additional considerations.
> >>I've seen it done, and it ain't straightforward.
>
> Nate Knutson wrote:
> > Any information about how well this worked once it was set up? (I
> > assume they had it set up with a normal brake lever as opposed to using
> > it as a drag brake?)
>
> They are or were the standard tandem drag brake for years.
> SImple effective cheap . Yes compatible with standard ( not
> 'linear' ) levers.
>
> You would have to widen the fork and get a longer axle to
> make this go - very one-off.

Maybe not.

Some decades ago I mouted a disc brake on a freewheel hub, and put it on the
front; didn't need to widen the forks, but I had to pick and choose the
cones to make it fit.

[JeffWills]

Nate Knutson wrote:
> JeffWills wrote:
> >
> > You could attach one of these to a rear freewheel (threaded) hub and
> > use it on the front, but there's a bunch of additional considerations.
> > I've seen it done, and it ain't straightforward.
> >
> > Jeff
>
> Any information about how well this worked once it was set up? (I
> assume they had it set up with a normal brake lever as opposed to using
> it as a drag brake?)

They were used on a couple of Seattle-based homebuilt recumbents.
Seattle's pretty hilly, and both riders are still alive, so I *assume*
they worked good enough for road use.

Jeff

[Werehatrack]

On Sat, 1 Apr 2006 19:42:33 +1100, meb
> wrote:

>
>Can I take a drum brake and mount the rotor on a non drum hub to some
>plates inside the flanges and spokes and secure plates through the
>spokes and flanges via bolts? Seems it might put some stresses on
>spokes in directions they were not designed to handle so might bend.
>Anyone tried this and had success or failure?
>Anyone think it would work/fail?
>If so why/why not?

Bad move. The heat transferred through the spokes will melt the wax
on your wings.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

[Chalo]

A Muzi wrote:
[re:Arai drum brake]
>
> They are or were the standard tandem drag brake for years.
> SImple effective cheap . Yes compatible with standard ( not
> 'linear' ) levers.
>
> You would have to widen the fork and get a longer axle to
> make this go - very one-off.

I bought a large number of Sachs hubs a few years ago that I believe
were intended for mounting an Arai drum on the front. So far, I have
only raided a few of them for axle kits.

These hubs, which came in factory cartons, use Sachs "Rival 7000"
threaded rear shells fitted with 9mm front QR axle kits. The axle in
each of these hubs is the usual length, suitable for a 100mm fork, but
the over-locknut dimension is only 96mm-- and the extra axle length is
slewed entirely over to the threaded end of the hub. They would need
some sort of axle spacer even to be used as a regular front hub.

Unlike most hubs for utility-bike applications, these are drilled for
32 spokes.

All the Arai drums I have seen are drilled for 3/8" or 10mm axles, so
these hubs would require either some sort of precision sleeve washer or
else a special 9mm version of the Arai brake.

Chalo Colina

[JeffWills]

Chalo wrote:
>
> Unlike most hubs for utility-bike applications, these are drilled for
> 32 spokes.
>
> All the Arai drums I have seen are drilled for 3/8" or 10mm axles, so
> these hubs would require either some sort of precision sleeve washer or
> else a special 9mm version of the Arai brake.
>

Very interesting...

The QBP catalog lists an Arai brake for *9.5mm* axles:
http://harriscyclery.net/page.cfm?PageID=49&action=details&sku=BR5003
which I assume is for solid axles. Your hubs are truly odd, indeed.

Jeff

[Chalo]

JeffWills wrote:
>
> Chalo wrote:
> >
> > Unlike most hubs for utility-bike applications, these are drilled for
> > 32 spokes.
> >
> > All the Arai drums I have seen are drilled for 3/8" or 10mm axles, so
> > these hubs would require either some sort of precision sleeve washer or
> > else a special 9mm version of the Arai brake.
> >
>
> Very interesting...
>
> The QBP catalog lists an Arai brake for *9.5mm* axles:
> http://harriscyclery.net/page.cfm?PageID=49&action=details&sku=BR5003
> which I assume is for solid axles. Your hubs are truly odd, indeed.

They are so odd that I haven't yet been able to put one to proper use.
And I bought four cases of those hubs. At least I didn't spend much on
them!

FYI-- 9.5mm = .374" = 3/8" within applicable tolerances. The bicycle
axle standards that are called "9.5mm" are in fact 3/8"-24 and 3/8"-26
threads.

Chalo Colina