Disc vs. Drums XO class 9"

[Jeff Brock]

Hey Folks ,

I am working away on my Buick XO class car . It will be close !

I had a little gear lube leak on my "good used" , now very modified rear end , so I tore it down today and will reassemble tomorrow.
This offers me a brake option I hadn't planned on.
I have either the big {73 Lincoln} drums that are from this 73 , 9"
or I have a complete 90's model 9" disc set-up .
I am only running rear brakes .

I scanned / searched ... did not find this LSR debate.
Any quick thoughts or advice?

Keeping in mind 4500-5000 rpm  130 to 150 mph.

Thanks ,

Jeff Brock

[Glen]

At those speeds the drums will do the job as there is enough shut off area on the courses to slow down and turn out.

[CNC-Dude]

 I generally have vehicle weight and the given distance to stop in to consider. Drums might be perfectly fine, given 1/4-1/2 a mile to come to a complete stop if needed. Many people probably like to have the piece of mind of discs all the way around, it might just be a preference issue. Back in the 40's and 50's on the lakes and salt as well, drums were mostly all they had, even on belly tanks that went around 200 or faster. It worked for them, but modern stuff is always nice too.

[Glen]

The two short courses have 2 miles of shut down plus the distance to the return roads.

[bvillercr]

You would get more stopping power in the front rather that the rear, of course there could be circumstances that might make that difficult to do.

[RichFox]

I like drums. You can back them way off and have no drag. Brakes are mostly for pushing it around the pits. How about some pictures of this beast?

[Jeff Brock]

backed off drums it is .

Pics have got to come soon .

Rich , I think you'll like it for a "quicky" build .
Three people have photographed it in the last week , but none sent to me yet.


Thanks guys !

Jeff Brock

[jl222]

Rear brakes only, might just lock up and slide

       JL222

[RichFox]

Rear brakes only, might just lock up and slide

       JL222

If you really need brakes, rear only are almost worthless in my experiance.  They do just that. But I have never really needed brakes on the salt or lake. Hope I never do. Sounds like things would have to be really out of hand to really need brakes.

[jl222]

  But they can get out of hand as I've posted before on brakes. I torched a hole into a waterjacket at 267 mph which pressurized the cooling system and blew a water hose off the engine this steamed up the window and I was driving blind, our 4 wheel brakes and 2 parachutes resulted in the course worker saying ''man you sure stopped fast''
  And fires can happen which is one reason were not to interested in Blown nitro.

             JL222

[doug odom]

Its not the type of brakes you have that limits how fast you can slow down as much as the amount of rubber you have on the ground. The limiting factor is the skinny tires we use. I set my cars up so you have to push real hard on the brake pedal to lock up the brakes. Those tires cost a lot of money and you don't want to look them up and skid of them.

[Seldom Seen Slim]

On a different vehicle -- but still brakes -- I'll usually back off the pucks on the front discs on the bikes (if we're even running front brakes), and back off the rears, too.  There's enough wind resistance and compression braking that I can turn out at the 6 or first turnout past the six -- without having touched the brakes.  And then I coast to the return road and used "Fred Flintstone brakes" (I drag my boots) to reach zero. 

Although there was that once when I ran the bike at Maxton just a few days after World of Speed.  I went through the lights and grabbed the front brake lever (fronts are required over 175 at Maxton) and squeezed and squeezed and had a few "O S**T!" moments before they finally came up and worked.  Motto:  If you loosen the brakes -- use 'em before you might need 'em.

[gearheadeh]

I like drums. You can back them way off and have no drag. Brakes are mostly for pushing it around the pits. How about some pictures of this beast?

So tonight I had a question and found for the most part my answer... thanks to the search function!

Is there some merit in thinking of the potential extra wind resistance from a front disc brake vs a drum?

[BALS aSALT]

i would be more apt to worry about rotating mass. disc is lighter. less stress on suspension, as if going fast on the salt is not stressfull.

[floydjer]

You would get more stopping power in the front rather that the rear, of course there could be circumstances that might make that difficult to do.

Of course, If you built a roadster, half the time they WOULD be front brakes