8-lug brake cooling
 

This 'letter to the editor' was in a 1964 Hot Rod Magazine. Interesting validation of the commendable brake cooling capabilities of Pontiac 8-lug wheels- straight from Kelsey-Hayes who designed and built them.

[Anybody know how to up-size this image?]

I have that same issue and remember the letter. If I get a chance I'll see if I can find the magazine and scan it.

I've had a few conversations with a retired engineer from a Tier 1 OE who manufactured many of the famous Muscle Car wheels.

They did a great deal of testing in the 60s, and found the Pontiac 8-Lug and Buick 12" Finned Drum to be the equal or superior to the disc brakes of the era. The key for both is getting airflow over the fins to get a good temperature delta. They work just as advertised. Problem is that Pontiacs and Buicks had a lot of body wrapped around those wheels! I didn't think to ask if the 'scooped' backing plates such as found on drum equipped big tank/big brake Corvettes would be helpful.

Main drawback of the drums was if the drums got wet such as in a deep puddle, etc. they too much longer to become fully effective again than discs.

The other issue with the 8-lug is that drum is highly sensitive to even minor distortions post machining, which cause the annoying pedal flutter. K-H reached out to find a solution - only reliable answer was to cut the drum with the rim and tire bolted into place, which was impractical for production.

As Paul Harvey would say: "Now you know..... the REST of the story!"

Interesting that then as well as now people still call those wheels aluminum.

8 lug brake cooling
 

Rag Top Man, I can appreciate what you are saying about the drums distorting. I think about this every time I have to remove and reinstall a wheel. I take great pains to use a crisscross pattern when tightening the lug nuts and I always use a torque wrench and bring them up to 90 ft lbs in two stages. Of course this is all probably wasted effort when I think of all the times in the past that some tire store gorilla attacked them with an impact wrench. If this happened(likely, I would guess over the decades before I put them on my car) I figure I'm at least not making them any worse.

I have had good success machining 8 lug drums with the wheels on and torqued on the brake lathe. It's a time consuming ordeal for sure. As they reach their discard diameter, it's more important than ever to have the shoes arched.

Don't know where your from but arching shoes these days is illegal, and it's been illegal for quite some time. I remember when we had to give up our machine.

Huh?:confused:

I just had a set arched last week

Had a set arched last November, did'nt see any Government officials.:confused:

I assume you're referring to re-arcing shoes with asbestos in them.

Sounds like they are looking at asbestos... the good old linings had it. :guitar:

But if you had non-organics, I don't see what the issue would be.