2013 Order Guide Released

[danyall2010]

Originally Posted by imccrea

That was listed as a Focus S which obviously has drums, now different publications have different specs as Ford doesn't list it nor does Hyundai. But still a lighter weight vehicle with 4 wheel disc should stop quicker than a Focus with rear drums you'd think?

Since the front brakes does about 75% of the stopping, it depends on what the front brake size and design is. Typically in a front wheel drive car, most of the weight is in the front (perhaps up to 2/3). When you brake, the weight shifts to the front, thus giving the front brakes more work. Naturally, many cars with rear drums will pull an acceptable (or sometimes above acceptable) distances.

The concern is what happens when you add weight to the back, whether it is people and/or cargo. In this type of situation, you will have more weight, giving the back brakes more work. The weight distribution changes. Disk brakes have better cooling than drums, resulting in less fade. Although drum brake design is getting better, the possibility of fade is still there and it is possible for it to overheat more quickly.

I am wondering if journalistic publications should give distances empty and fully loaded so we can get a clearer picture.

I hope my explaination makes sense.

[red2009se]

Originally Posted by Kabigon

Yes, and the Mustang V6 performance package was replaced by the Boss 302.

Apples and oranges.

Oh haha. There is a base level ST, not just a high priced level as was predicted for months. So, yeah, the Sport was swapped for ST.

[MyThIc3LiTe]

You don't really need rear discs on cars like this since all the stopping is done by the fronts.

Even performance orientated cars have massive front brakes with bigger callipers with amusingly small discs on the rear.

Given how all the weight on the Focii is in the front, I'd rather they beef up the front.

And costs, discs > drums in costs. If you are buying a base Focus chances are you don't care for discs and don't want the added costs down the line.

[Pretherius]

Aside from the safety issue (which, yes, is a big issue), are drum brakes even cheaper to make than discs? My whole beef with this is that it has to cost very nearly the same or perhaps even less to make discs, plus consider the logistical simplification from putting discs on at the factory and never even stocking drums and shoes and springs and clips and star wheels etc. I do imagine calipers are the major cost but those can't be that much more than drum brake cylinders...

I utterly hate working on drum brakes:

With discs, it's typically 4 bolts per wheel, compress the piston, and put it back together. You can do a front disc job with new pads and rotors in well under an hour.

With drums... 1 hour trying to make the brake spoon engage the star wheel and fail, 30 minutes trying to pry the drums off the pad and fail because of the rust lip on the drum, spend 2 hours hammering off the old drums in half-inch chunks, undo all the springs and pins without cutting a gash through your hand, try to reassemble new hardware (you DID buy new hardware right??) and realize you should have left the other side intact until you put this side back together because you can't remember how everything should connect. 6 hours later and it's good as new. Not to mention your brake shoes had lots of life left in them but you couldn't tell that because you can't see them easily without removing the drum...

What a damn hassle. All so car companies can sell you on an "upgrade" to safety equipment that be standard. I've got ABS, ESC, TC, and a billion air bags, but I still have to pay extra for rear discs...

[kam327]

Apparently Bendix did a study on discs vs drums on semi's. Not directly applicable (best I could google on short notice) but perhaps something can be taken from it:

A study comparing the braking effectiveness of air disc brakes versus air drum brakes for tractor-trailers was conducted by Bendix Commercial Vehicle Systems. Tested at 60 mph, the disc brake stopped the vehicle at about 200 feet and the drum brake did so at about 270 feet. This braking distance difference is the result of the different braking systems. After 15 stops from 60 mph, the stopping distance for the drum brake deteriorated from 270 feet to 450 feet, while stopping distance for the disc brake remained at close to the initial 200 feet. The increased braking distance for drum brakes at successive stops is the result of brake fade.

http://www.fmcsa.dot.gov/about/outre...chnologies.htm

[kam327]

Disc brakes... dissipate heat better (brakes work by converting motion energy to heat energy). Under severe usage, such as repeated hard stops or riding the brakes down a long incline, disc brakes take longer to lose effectiveness (a condition known as brake fade). Disc brakes also perform better in wet weather, because centrifugal force tends to fling water off the brake disc and keep it dry, whereas drum brakes will collect some water on the inside surface where the brake shoes contact the drums.

http://cars.about.com/od/thingsyoune...discvsdrum.htm

[Pretherius]

I don't really feel like fade is a significant concern here, unless you're racing. You're never going to go balls-out 0 to 60 to 0 fifteen times in a row. Even in city traffic, if you get from 0 to 40 to 0, it's going to be more gradual and you'll likely be waiting in traffic at lights as the brakes cool.

I'm sorry though, I just don't see any benefit to drums except that they make discs a selling point.

[MyThIc3LiTe]

Originally Posted by Pretherius

I don't really feel like fade is a significant concern here, unless you're racing. You're never going to go balls-out 0 to 60 to 0 fifteen times in a row. Even in city traffic, if you get from 0 to 40 to 0, it's going to be more gradual and you'll likely be waiting in traffic at lights as the brakes cool.

I'm sorry though, I just don't see any benefit to drums except that they make discs a selling point.

Costs.

Small cars don't need that much stopping power when all the weight is on the front.

The rear brakes can't do much to help there.

[kam327]

Originally Posted by MyThIc3LiTe

Given how all the weight on the Focii is in the front, I'd rather they beef up the front.

Originally Posted by MyThIc3LiTe

Small cars don't need that much stopping power when all the weight is on the front. The rear brakes can't do much to help there.

That sounds a little glib to me. I've read the Focus's weight distribution is 58/42. And that in general small cars' front brakes do "up to" 70% of the work. Driving around my kids I'd want to have all the stopping power I can. And really, how much more expensive is it to service the rear disc brakes versus drums? An extra $50 or so every 40,000 miles? Peanuts...

[csvt2060]

Several of you guys have the physics all wrong. Whether the mass is on the front or rear, the brakes overall are still slowing down the same amount of mass. The difference between the front and rear brakes is the available traction to the tires, which does increase to the front as the load shifts. That's why the brakes are set with a front bias.

I was hesitant to add to the OT topic, but too much bad information. Back to the topic.