Drum Brakes and Disc Brakes, A Historical Question

Speaking of Metros..

A friend of mine in HS had about 5 of those. His last name was
"Hudson", and he claimed it was one and the same with the Hudson
Automobile company that got absorbed into Chrysler. Says his dad was
part of the Hudson RnD team and stayed on in Chrysler up into the 70s.

I always thought they were neat little cars, but I don't remember if
any of them ran or drove. They were all in a field behind his house,
along with some other stuff I have never seen before or since- most
notably a set of fuel injection heads for a 440, and a '56 New Yorker
with a 392 Hemi prototype in it, a pushbutton transmission, power
everything (windows, seats, steering wheel adj, mirror adj, etc) and
(of all things) a phonograph that could play 45s.


Btw, this has been an interesting thread to read, with all the
historical bits. Thanks to everyone who has chimed in!

-phaeton

Roger Blake wrote:
>In article >, John_H wrote:
>> You got the Slant Six and we got the Hemi. We also got our first disc
>> brakes on a locally built car in 1956 (Triumph TR3). )
>
>As I recall, here in the U.S. we got our first disc brakes on the 1949
>Crosley, which also featured an overhead-cam 4-cylinder engine.

Discontinued due to design problems shortly after its introduction
IIRC.

--
John H

John_H wrote:
> Roger Blake wrote:
> >In article >, John_H wrote:
> >> You got the Slant Six and we got the Hemi. We also got our first disc
> >> brakes on a locally built car in 1956 (Triumph TR3). )
> >
> >As I recall, here in the U.S. we got our first disc brakes on the 1949
> >Crosley, which also featured an overhead-cam 4-cylinder engine.
>
> Discontinued due to design problems shortly after its introduction
> IIRC.
>
> --
> John H

Discontinued which? The braking system, the OHC 4-cyl, or the whole
car altogether?

:-P

-phaeton

Roger Blake > wrote in
:

> In article >, TeGGeR® wrote:

>
>> ...and wasn't even made by AMC, but by the British Motor Corporation
>> of England on BMC's A30 chassis. It was sold as the Austin
>> Metropolitan in the UK.
>
> The Metropolitan was designed by Nash in the U.S. (actually an outside
> designer named Bill Flajole). It was determined early on in the Met's
> design that it would be built overseas to take advantage of lower
> labor costs and to get around steel shortages in the U.S., Fiat was
> initially considered, Austin ultimately chosen. There was a book
> called "The Metropolitan Story" that came out a few years back that
> goes into the car's history in great detail, and of course much may be
> found on "thuh web," such as:
>
> http://home.insightbb.com/~hoosiermets/page11.html
>



I had a look at that page. And this one:
http://en.wikipedia.org/wiki/Nash_Metropolitan

They say nothing about what Nash ended up using as the basis for the
Metropolitan. The Wiki page does say the car was built using "existing
mechanical components". The Met was built using the Austin A30 chassis
and (originally, apparently) the Austin A-series engine. I suspect Bill
Flajole ended up contributing little outside of the body styling.

The identical chassis and engine family was used for the original
Austin-Healey Sprite, although the original Sprite never received a
B-series engine.



--
TeGGeR®

On 25 Sep 2006 19:29:19 -0700, "phaeton" >
wrote:

>In the early part of the last century, there were a lot of different
>styles of brakes. Seems that we all settled on the internal drum brake
>for a good part of the century.
>
>Drum brakes worked. They stopped the car.
>
>
>Thing is, we all know these days that disc brakes are superior. Better
>stopping power, better cooling ability, self-adjusting for wear, etc.
>The thing that I can't seem to wrap my noodle around though, is why
>didn't we see them sooner? Compared to drum brakes, disc brakes are a
>much simpler design. I would wager that it is even cheaper to make
>disc brake sets. The master cylinder is irrelevant- same concepts
>apply, just different front/rear proportioning.
>
>I realize that in manufacturing, *nothing* gets changed unless there is
>a damn good reason to. But why did it take until when.... Late 1960s,
>early 1970s or so until FRONT disc brakes became the norm? How come it
>took until now for them to start showing up on the rear wheels?
>
>Was there some enabling technology or manufacturing process that needed
>to be developed or invented that made disc brakes possible? I can't
>seem to think of anything disc brakes require that drum brakes didn't
>already have. Why didn't disc brakes become the norm instead of drum?
>
>Or is this another thing where the rest of the world had 4-wheel disc
>brakes since the 1950s, but Detroit refused to 'progress'?
>
>discuss!


It may seem surprising but not everyone considered them superior to
drum. I recall an article back in the 60's in Popular
Mechanics/Science. Smokey Yunich (probably misspelled) was one of
there regular writers and had been, and perhaps still was at the time,
a well known stock car racer. He believed drums were superior and
wrote about it in a "debate" in the magazine with someone else who
argued that disks were superior. There is something to be said for
drum brakes, you'll notice they are still in widespread use on 18
wheelers.

TeGGeR® wrote:


> Didn't pretty much every NA manufacturer move to single-piston floating
> calipers by 1968?

Well, Chrysler A-bodies (Dart/Valiant/Duster/Demon) stuck with 4-piston
disks through 72, changing to Kelsey-Hayes floating calipers for 73.

Roger Blake > wrote in
:

> In article >, TeGGeR® wrote:
>> They say nothing about what Nash ended up using as the basis for the
>> Metropolitan. The Wiki page does say the car was built using
>> "existing
>
> You might want to look up the book "The Metropolitan Story" if you are
> really interested, as it goes into minute detail about how the
> car was developed. The front suspension was unique to the Met
> and was Nash-style with the springs high up on the upper control
> arms. I don't know if the floorpan (it's a unibody car, so no
> "chassis" in the sense of a separate frame) is shared with any Austin
> models of the day. The initial prototypes were made using Fiat running
> gear.
>
> Engine and drivetrain of production models were 100% Austin, though
> interestingly the 4-speed gearbox was converted to 3-speed by locking
> out first gear. (Nash did extensive consumer research and drivers at
> that time were accustomed to 3-speed tranny with column shift.)
>




Your implication is that the unibody may be unique to the Met. I'm sure
you're right, but...

Taking your advice, I did some Internet searching and came up with a
bunch of Met sites. As an aggregate, they indicate that the engine,
transmission, brakes, steering, rear axle, and at least some of the
suspension were straight carry-overs from the A30 and the A40.

Given the Met's low selling price, small volume, and high parts-bin
content, I just find it kind of hard to believe Nash or BMC would have
tooled up an entire new unibody when they already had the A30's to work
with. Having seen both up close (while lacking a measuring tape at the
time), I'd swear the Met and the A30/A35 are the exact same wheelbase
and track width.


--
TeGGeR®

Ashton Crusher wrote:
>> Or is this another thing where the rest of the world had 4-wheel disc
>> brakes since the 1950s, but Detroit refused to 'progress'?
>>
>> discuss!
>
>
> It may seem surprising but not everyone considered them superior to
> drum. I recall an article back in the 60's in Popular
> Mechanics/Science. Smokey Yunich (probably misspelled) was one of
> there regular writers and had been, and perhaps still was at the time,
> a well known stock car racer. He believed drums were superior and
> wrote about it in a "debate" in the magazine with someone else who
> argued that disks were superior. There is something to be said for
> drum brakes, you'll notice they are still in widespread use on 18
> wheelers.

There is one area where drums are "better" - weight.
on my 76 Camaro, the front disks are the heavy parts, and all that mass
needs to be rotated. The rear drums are lighter than the rotors, and
the total mass of the disk assembly is definitely greater than the total
mass of the drum assembly.

That said, I'll take the weight penalty with disks 11 times out of 10 on
any car that I'm working on. I hate drums.

I had a web page showing the weights, and it was around 40 pounds
advantage for 4 wheel drums, but I've since lost the link, so don't
quote me on that.

Ray

ray wrote:
> Ashton Crusher wrote:
>
>>> Or is this another thing where the rest of the world had 4-wheel disc
>>> brakes since the 1950s, but Detroit refused to 'progress'?
>>>
>>> discuss!
>>
>>
>>
>> It may seem surprising but not everyone considered them superior to
>> drum. I recall an article back in the 60's in Popular
>> Mechanics/Science. Smokey Yunich (probably misspelled) was one of
>> there regular writers and had been, and perhaps still was at the time,
>> a well known stock car racer. He believed drums were superior and
>> wrote about it in a "debate" in the magazine with someone else who
>> argued that disks were superior. There is something to be said for
>> drum brakes, you'll notice they are still in widespread use on 18
>> wheelers.
>
>
> There is one area where drums are "better" - weight.
> on my 76 Camaro, the front disks are the heavy parts, and all that mass
> needs to be rotated. The rear drums are lighter than the rotors, and
> the total mass of the disk assembly is definitely greater than the total
> mass of the drum assembly.
>
> That said, I'll take the weight penalty with disks 11 times out of 10 on
> any car that I'm working on. I hate drums.
>
> I had a web page showing the weights, and it was around 40 pounds
> advantage for 4 wheel drums, but I've since lost the link, so don't
> quote me on that.
>
> Ray

I'm not sure that the weight thing is really that significant. If
nothing else, the rotational inertia of a drum is likely greater than a
disc of equal diameter, even if the total weight is the same or less.
So you might win some on unsprung weight, but lose on rotational inertia.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

"Nate Nagel" > wrote in message
...

>
> I'm not sure that the weight thing is really that significant. If nothing
> else, the rotational inertia of a drum is likely greater than a disc of
> equal diameter, even if the total weight is the same or less. So you might
> win some on unsprung weight, but lose on rotational inertia.
>
> nate

I havent done any calculations, but intuitively it would seem that
rotational inertia would not be greatly different,
and wouldnt be too big a deal anyway. Have you put a pencil to it, Nate?