BowtieFever

I was wondering if it would be worth it to get a set of aluminum drums over my steel ones. What is the weight difference?

ede

several pounds, lot depends on how you define "worth it"

naf

iTrader: (7)

Weight is not the only benefit, aluminum drums dissipate heat better and should be more resistant to brake fade.

BowtieFever

Do you know what years and specific models came with the aluminum drums? Thanks

Gumby

IMO

If ya find a set. put them away on a shelf and sell them in 20 years to someone restoring a showroom car for big bank.

some weight savings yes but not one safety benefit. actually it goes down. as they can and do come apart easier like anything aluminum, with heat and stress. You be better off going disc brakes. Espically if you do any racing, even just street.

Aluminum drums are "neat" but steel is safer. But they are worth hanging on to. They are worth some coin now but will be worth more later.

TKOPerformance

My car has them ('86 IROC Z28).

They aren't available new anymore from what I've heard. I rebuilt mine out of necessity. Eventually I want discs.

naf

iTrader: (7)

Gumby-what else do you know about this defect with the aluminum drums? Are you primarily concerned with an inherent property in aluminum - ~2x thermal coefficient of expansion vs. steel/~ 1/2 the strength type thing or is it a design/casting issue specific to our drums?

Not trying to argue, just looking for more info.

Gumby

Just from what I see, read or hear in the scene about people almost killing them self at the drag strip as a aluminum drum shattered. granted most of these are classic cars with drums all around. Trying to save on weight instead of just upgrading the system. Does it happen all the time, no. Can it, yes and more likely to happen with aluminum then steel.

I don't think it happened yet but there was rumor of a 1/4 time ban on aluminum drums at the track for the same reasons.


Id say its time that is the big factor. When your buying used parts you have no idea how they were treated or abused. Why put your life on the line to save a few lbs???

They should be well inspected and checked if your gonna put your safety seal on them.


I don't like aluminum rims for the same. Known way to many people who had a rim walk right off the lugs. as everything else held but the aluminum gave. Most were lucky and not at a dangerous speed.

Its kind of like take a 4x4 block of steel and a 4x4 block of aluminum. Take a 5lb sledge hammer and have at it.

shaped n formed aluminum parts can be "stronger" and "better" but steel is steel. Its takes abuse and ask for more.

Forshock 85TA

did you guys notice his avatar

(im a steelers fan myself)

406TPI

iTrader: (1)

My 85 IROC had them stock with a 3.42 OPEN rear. Stange combo if you ask me I just have them sitting on the self collecting dust and hopefully some big coin one of these days.

Pat Hall

iTrader: (31)

Hmmmm, must not be that strange of a combo. I've got the exact same rearend sitting on the back porch with the ends bagged up to keep out the rust. The guy I picked it up from said it came from a mid eighties IROC as well. I have a disc rear under the car now, but I ran the other rear with the aluminum drums without any problems for a couple of years.

Rick King

1 pound of rolling weight s = to 10 pounds of dead weight in the quarter

later and
GB

rick

Justins86bird

1 Al drum is approx 5 pounds lighter then the steel one.

Confuzed1

iTrader: (4)

I have them. The originals that came in '83.

They stop nice I think. If you ask around, some say they stop as good if not better than disc brakes. I've had cars with drums all around, but the rears on the Camaro have never faded, the aluminum helps with that.....besides, they don't rust!

MNformula350

iTrader: (2)

I have 2 pairs, i use them because it takes less power (not much i know) to turn them (which is why i also have an aluminum driveshaft) at the track. My Formula is a autocross car, so the less it weighs the better. I am shooting for 3000lbs.

TKOPerformance

The biggest differences in the material between steel and aluminum are heat handling properties, and the way the material fails. Aluminum spreads the heat through the part, whereas steel or iron keeps the heat more localized. This is why aluminum heads will tolerate more compression that iron heads, but they also need the extra compression to make up for the fact that the chambers run cooler.

Steel is a lot more plastic than aluminum. If you cold form aluminum into a bend, and then undo the bend the aluminum will most likely break. Steel can be folded back and forth several times before failing.

Nowadays the strength factor is basically irrelevant. There are aluminum alloys that are just as strong as steel, but significantly lighter like Duraluminum. Every alloy has its own set of properties and drawbacks though, which is why manufacturers match the material to the application to ensure safety.

I've never seen a brake drum fail, unless it was turned past the specified maximum limit, and that being the case the failure wasn't the fault of the material, but the mook who ignored the information stamped into the drum.

ME Leigh

Sounds like user error, or negligence!

Gumby

I assume though that aluminum drums has steel sleves. I can't see aluminum lasting with the grip new pads they make today.

---------

But there are plenty of other ways to lose 10lbs and really. You want to lose weight in the front, not the rear. 49/51 ratio is the best.

Id find other way to lose weight. If its only weight your looking to lose.

but it of course just my 2 cents.

Confuzed1

iTrader: (4)

Yeah, I think they do have steel inserts - heck I think they'd almost have to.

I've been tryin to lose weight for years...but I just can't seem to keep it off. Oh.......- you mean the car.

Night rider327

iTrader: (13)

And for the info you really wanted.....

9 lbs saving for the set

Thats going by my 88's iron drums vs. the junkyard early third gen alum. drums I got.


My iron ones was 29 lbs for the set, and the alum. ones is 20

The alum drums was used on every RWD car from late 70's to late 80's and S trucks.

Not all cars will have them though... I had to look through about 40 cars to find 3 sets.

1 from an early third gen, and 1 from late 70's G body, and one from mid 80's G body.

And TKOPerformance. Is right. YOu can't buy them new anymore, so junkyarding is the only way you'll find a set (or ebay if you wanna shell out big $$$... The go for $60-100 a set on ebay.. I got mine a junkyars for $10 a drum)

Gumby

After lookin the problem you need to look for is stress or hair line cracks around the bolt pattern. Thats where they will start. Then they travel up the side and the brakes force them to split open on a hard run stop.

ME Leigh

Yeah user error or negligence.

jmd

iTrader: (4)

Can you get alum. drums resleeved when they are too thin to be turned?

Gumby

And when your buying parts that you can only get used, you have no idea how someone treated them.

blacksheep-1

My 83 Z28 also had aluminum drums on the rear. Seems like they were pretty common. What probably happens is that they wear out and get replaced by (cheaper) steel ones.

84L69TA

Im looking to get rid of a set off of an 88 TA that are in beautiful condition. The car only had 50,000 miles on it when they were taken off. As I said, they are in perfect condition if anyone is interested. Located in Phoenix AZ. PM if interested.

flowmasterchevy

Im not sure about F-Bodies, but the mid 80's G-Bodies like the Grand National that had the aluminum drums had open rearends. Not sure if it was always aluminum drums-open rears or if they had some aluminum drums-posi rears.

jmd

iTrader: (4)

That's how it usually went: open rears in the Buicks. The GN really didn't often get alum. drums. The T-type & Turbo T did.

If you look at the svc. manuals, the cars with wimpy rear gears like 2.29 were slated to get alum. drums from the factory.