Are Front Disc Brakes Overrated?

Has anyone performed this braking test on their cars(mfgrs take note)?

http://www.1800vw.bizhosting.com/brakehowto.htm

see the beginning and end of this interesting article On dune buggy brakes .(says do the test on STREET or rough)
since the early Porsches often came with front end weights, I'd think that its applicable.
Upshot I got was if you run near-stock tire size, you need LESS front brakes not more!

Quite possible that the only benefit of F.E.discs is less frequent adjusting needed?!
Also maybe why so many owners soon add rear disc pkg. after they do their fronts.
I C $$ people...

TheDaveCave

I have had 14 buggies over the years and the article is more or less correct. I never even ran brakes on the front of most of mine. However, it is off for speedsters. Speedsters have a weight bias much closer to a bug and therefore need more braking up front.

After 3 speedsters I can say that discs up front much improve stopping power, especially if you have a flared car and are running wide wheels. My current car had brand new drum brakes all the way around and I couldn't hardly stop the thing, even after adjustment and bleeding. A nice inexpensive set of disks cured that problem.

Disks make a huge difference.

Front disks are the ONLY way to go in a Speedster, unless you have an genuine Porsche drum upgrade available to you.

Disks are a far more controlled system, run cooler for extended driving in traffic and grab better, even hot, than a drum set-up does warm.

The disks are always in adjustment and grab equally each time, no pulling to the right or left in an emergency situation. Drums are manually adjusted and often result in one grabbing before the other. (There are only three feet between the high speed fog line and the guard rail. A panic stop and a hard pull to the left happens before you can THINK of it happening. Instinct.)

Plus, a Speedster, or any other sports car, is built to perform to the limit of it's components. With a light weight body, built engine, precise shifter/transaxle, upgraded suspension, etc., etc. you KNOW that you're going to push it, if only occasionally. You'll need every advantage in stopping it.


Hey . . . remember, "Be CAREFUL out there . . . "

It's nice to be able to stop--reliably. As others have said VW front drum brakes won't--reliably. IMOP one of the best performance upgrades I ever did on my old bugs. The faster you go the more important it is%)

I agree with Fred.
Drum brakes were unreliable. They usually pulled to one side or the other.
If you overtorqued the wheels (especially on wide 5's), the drums would distort. The out of round drums now are less efficient. The feedback from bounce or vibration this causes can be felt when under heavy breaking.
Disk brakes front and rear, now stop reliably without pulling to the side.

Greg B

Discs work better in the wet too -- but who drives a Speedster when it rains. Drums can fill with water (even a little is bad) and take a few tries to dry them out enough for them to work effectively.

Add to all that was said before that drum brakes in Bugs were somewhat deficient and that most of our cars don't have the original German brakes anymore but replacement or aftermarket drums of questionable quality and it's even worse.

THX for all the very civil replies. My first post to ANY forum. Has anyone who has done the front disc conversion noticed the 'heavier' steering due to the increase in unsprung weight? ( see article 2nd paragraph)

http://www.chtopping.com/CustomRod4/

thxTDC

Mulder said it best, "I am officially a horses ars"

TDC

Are Front Disc Brakes Overrated?

Right up to the moment of impact!


Seriously, If you are ordering a car, just do it right and put them on the front as a minimum, but if you are going for anything with power, do all four. Me? After two Speedsters, I would do all four in a wide five pattern and your car will be set up for any engine and some factory looking steel wheels.

I have had drum brakes on 2 Speedsters and 1 Spyder. I left the drum brakes alone on the Speedster that had an 85 hp engine. The car was generally just for "puttering about" rather than any spirited driving. The 4 wheel drums worked well in this car.

The 2nd Speedster received a 150+ hp engine, I first went to disks on the front, shortly there after went to rear disks also. While some fair number of people seem to want to argue about it, 4 wheel disks do stop better than 2.....time after time.....

In my Spyder I went through a similar process, drums, 2 wheel disks, then 4 wheel wide 5 disks. Car now stops hard, fast, and straight, time after time. I did several stops with the drum disk combo then did several with the 4 wheel disks....I averaged over 10' shorting stopping distance from 60 mph with 4 wheel disks than with 2. My testing was pretty unscientific so your results may vary.....

As to the question of unsprung weight, yes, I think there is a noticable difference. I would prefer aluminum hubs and calipers on all 4 corners as well as mag rims but that would cost another $5k or so....right now I want to be able to stop at least as fast as the guy in front of me, given the traffic I drive in...that is the goal, and the 4 wheel disks got me there.

Another consideration for drum brakes is water. Driving in the rain is OK but if you get in water deep enough to get inside the drums you have basically no brakes until they are dried out. Left foot brake 'em till the water vaporizes. Disks don't care as the water gets squeeged off.

4 wheel discs are definitely better but it is also possible to upgrade the stopping power of the rear drums by using Super Beetle front wheel cylinders on the rear. I did this with my first set of Jamar front discs and lowered spindles on my old "74 beetle. A little extra trouble to bleed but an economical way balance the additional up front stopping power of front discs. The car would squat'n'stop very well.

I must disagree with some points the article you are referring to has made. First, adding unspring weight does NOT make your car ride "rougher". In fact, it usually has the opposite effect of making the suspension soften due to the extra weight. As the existing spring/shock combination now has more load at the end of the a lever (your suspension arms), the heavier unspring weight can actually MAKE the suspension bounce around. Removing unspring weight, either from the brakes, wheels or even the tires, has the effect of making the suspension somewhat more firm. It also allows quicker acceleration and deceleration (braking).

The total weight that is unspring is only part of the equation. Weight that rotates has MUCH more effect on steering, suspension and braking. The further the rotating weight is from the center, the great its effect. Drum brakes place most of their weight well away from the center. And that mass rotates. Whereas the disc brake calipers are much heavier than the drum wheel cylinders, neither rotate so the effect is not great. But the drum DOES rotate and its heaviest portion is the furthest point away from the center so its effect is very noticeable.

The actual weight difference they are mentioning in the article does not seem correct. To see the difference, you must do an apples/apples comparision. You cannot take off stock drum brakes, replace them with really really cool 4piston ventilated 12 inch rotors and state that the drum system weighed less. You've replaced it with something that works about 3 times better!! Apples/oranges. Here's apples/apples. On commercial freight trucks, especialy tank trucks, disc brake are becoming more common. With huge mass to to stop, these brakes work very hard. The disc brakes that are installed on these vehicles are designed to be on par with the drums on cold stops. Once the drums get hot, its all over and the discs just blow the drums away. Okay, so cold stops these brake systems are comparable. Guess what? These commercial trucks are saving 60 to 70 pounds PER wheel by going to disc brakes. They are much more expensive and require significant retrofit yadaydayada. But when a comparable system is compared head to head, disc are actually lighter.

It is unlikely with the system you have now, that you will notice any change in "handling" by switching to discs. The change is just not that dramatic (weight wise). However, the braking will be HUGELY better. Switch. For all the right reasons. angela

I have the hardest time understanding women, most of the time, but I have learned one thing..Just agree with whatever they say so...using that logic I agree with Whatever Angela said, 100%.......
I may be mechanically declined, but I'll take disc over drum every time....