Brakes: anybody running aluminum drum brakes?

[t walgamuth]

anybody running aluminum brake drums?

[skyway]

? Like Buick?
Those, a trunk mounted battery, and a belly pan, were a large part of a 50’s “how to” do an early C-K article that was reprinted in the Turning Wheel mebbe 30-ish years ago.

[t walgamuth]

I am wondering if any of the places like Summitt offer aluminum brake drums drilled as you need them..?

[gordr]

What I would like to see is aluminum brake rotors with replaceable steel friction surfaces. Combine with aluminum calipers, and you might be able to have disc brake effectiveness with less unsprung weight than stock drums.

[Rafe Hollister]

So a disc brake conversion weighs more than the stock drums?

[gordr]

So a disc brake conversion weighs more than the stock drums?

The after-market ones using the big vented rotors? Definitely.

[t walgamuth]

I'd say it depends on what you choose to do. A basic solid rotor and smallish caliper might weigh less. The main advantage is the ease of service and better braking performance.

[garyash]

Tom: Here's a kit to put aluminum drums on old Ford spindles:

https://www.speedwaymotors.com/Aluminum-Buick-Front-Brake-Drum-Kit-12x2-45-Fin-Plates-Hubs,383095.html

I have original Buick 12" aluminum drums on my Indy car. I should go weigh one, as they are not really light.

[PackardV8]

I am wondering if any of the places like Summitt offer aluminum brake drums drilled as you need them..?

There's drum diameter, friction surface width, spindle offset, bearing set, shoes, wheel cylinders, hoses and associated small parts to be considered, so short answer "no".

What I would like to see is aluminum brake rotors with replaceable steel friction surfaces. Combine with aluminum calipers, and you might be able to have disc brake effectiveness with less unsprung weight than stock drums.

The aluminum calipers have long been available and the more expensive aftermarket rotors have aluminum centers with bolt on iron rotors; steel is not a good friction wearing surface.

For cost-no-object-CASOs-need-not-apply, there are carbon fiber ceramic matrix rotors which are amazingly light; only about $1,000 and up each.




jack vines

[nvonada]

Running a 60-70 year old suspension design with steel wheels and a solid axle with leaf springs makes worrying about the unsprung weight of your brakes a idea to play with rather than a noticeable improvement to your ride, handling, or performance.

[gordr]

Unsprung weight makes a huge difference in how your car handles. Modern steel belted radials are much heavier than 6.70X15 bias tires, as are the rims needed to safely carry them. You put those on your Studebaker, and then add 12" ventilated cast iron rotors and the heavy cast iron calipers, and now your poor springs and shocks are trying to control about twice the weight they were designed to do. Of course, your ride quality is going to suffer.

[t walgamuth]

So nobody except Gary Ash is running any aluminum drums? If I could pull off my old drums and slide on a new aluminum one I could maybe save 5# per wheel? That is noticeable to me. I'll call Summit and see what they offer.

[PackardV8]

Yes, Summit has aluminum brake drums, but only in 9.5" diameter with 4.75" bolt circle. As I mentioned above, it ain't that simple as re-drilling the bolt pattern. Center hole, offset, shoe width, adjuster holes, all have to fit.

https://www.summitracing.com/parts/aaz-2c18001

Did we ever weigh the Studebaker OEM disc brake components and the OEM drum components and compare the two? IIRC, the disc setup was at least the 5# lighter you're looking for.

jack vines

[t walgamuth]

Did you ever weigh the Borranis and adaptors?

[garyash]

Tom:
Here are some weights on the Indy car:
Brake backing plates and shoes: 12 lbs
Hub: 8 lbs
Aluminum brake drum: 18 lbs
Wire wheel, 18" x 4" rim: 20 lbs
Tire: 6.00/6.50-18: 20 lbs
Spinner: 3 lbs

Total is 81 lbs on the front spindle and knuckle. However, I'm probably way ahead of what was originally on the 1929 President axle. It had 15" drums with 3-shoe rod-operated brakes, wood wheels, and huge rims and tires. The front axle with spindles weighs 92 lbs and each front leaf spring weighs 22 lbs. Rear axle is 175 lbs, 32 lb springs, 24 lb 7.00-18 tires. I only counted half the leaf spring weight as unsprung. With 2 passengers and 10 gallons of gas, I estimated the total weight to be 2700 lbs with 640 lbs of it unsprung. I wonder how that compares to a 1960's Studebaker and a modern car.




Wood wheel with steel hub, brakes, tire, and 15" brake drums from 1929 Studebaker President.


Aluminum 90-fin drum from ca. 1967 Buick Riviera with steel splined hub for wire wheels.