66 brakes
6th Gear Member
Joined: Apr 2007
Posts: 10,468
From: California
Discs have FAR more stopping power than drums, period. They're capable of applying much higher force to the pads because of extra pistons. More force = more friction. Yes, drum shoes have large surface area, yes they are self energizing....but there are 2 absolutely critical factors that determine stopping power. The compounds ability to handle heat, and the friction it can generate based on material spec within a given heat range.
In the REAL WORLD, drum shoes and drums retain huge amounts of heat while using poor compounds in terms of handling heat....that combined with the reality that there just are virtually no good shoe compounds available(at least not for our cars, with a few exceptions) means that ACTUAL drum performance is substantially less than discs with aggressive pad compounds.
THAT said, it's going to depend on vehicle weight, speed and tire size/traction. With small factory tire widths like 205's on normal tires in a light car like a Classic moving at moderate speed, they'll stop the first time every time just fine....repeated stopping is another story, since the drums can't shed heat fast enough. But larger tires, with stickier compounds, heavier cars and higher speeds ALL contribute to higher brake loads. Put larger extreme performance summer only tires on a Classic and go down the highway in full street weight at 70mph.....you are NOT going to stop as well with drums as you will with discs. The drums will build a fair bit of heat before you get to a stopped position, and you'll start to lose braking friction before you come to a complete stop.
Discs on the other hand generate MUCH more friction from pressure and use compounds that have higher friction coefficients and work in higher temp ranges. That means when you get on the brakes they immediately come up to an effective temp range and generate a ton of stopping power. If you have the tires to use it then you WILL stop faster.
Put huge tires on a classic like what the Vipers use(275 front 345 rears) and try to stop from 70mph. You might not even be able to get the tires to lock to begin with using drums, but you WILL have noticeable fade before you come to a total stop. Brakes and tires work together. Discs DO generate more stopping power, but it may simply be beyond what your tires can cope with. Larger tires that have more grip though, and you will quickly notice a difference in stopping power between disc and drum.
The only reason drums have been, and are still used, is because they're cheaper to manufacture.
In the REAL WORLD, drum shoes and drums retain huge amounts of heat while using poor compounds in terms of handling heat....that combined with the reality that there just are virtually no good shoe compounds available(at least not for our cars, with a few exceptions) means that ACTUAL drum performance is substantially less than discs with aggressive pad compounds.
THAT said, it's going to depend on vehicle weight, speed and tire size/traction. With small factory tire widths like 205's on normal tires in a light car like a Classic moving at moderate speed, they'll stop the first time every time just fine....repeated stopping is another story, since the drums can't shed heat fast enough. But larger tires, with stickier compounds, heavier cars and higher speeds ALL contribute to higher brake loads. Put larger extreme performance summer only tires on a Classic and go down the highway in full street weight at 70mph.....you are NOT going to stop as well with drums as you will with discs. The drums will build a fair bit of heat before you get to a stopped position, and you'll start to lose braking friction before you come to a complete stop.
Discs on the other hand generate MUCH more friction from pressure and use compounds that have higher friction coefficients and work in higher temp ranges. That means when you get on the brakes they immediately come up to an effective temp range and generate a ton of stopping power. If you have the tires to use it then you WILL stop faster.
Put huge tires on a classic like what the Vipers use(275 front 345 rears) and try to stop from 70mph. You might not even be able to get the tires to lock to begin with using drums, but you WILL have noticeable fade before you come to a total stop. Brakes and tires work together. Discs DO generate more stopping power, but it may simply be beyond what your tires can cope with. Larger tires that have more grip though, and you will quickly notice a difference in stopping power between disc and drum.
The only reason drums have been, and are still used, is because they're cheaper to manufacture.
6th Gear Member
Joined: Oct 2006
Posts: 6,417
From: Cork, Ireland
i changed to discs in front with a dual master and I'm never going back. if i buy another classic it's the first thing I'm doing again. I have no power brakes so the pedal effort is not much different, but it's easier to dose and and I feel I do have better stopping power.
changed the rear as well to discs, but only because they were 50$ difference (new drum set, new disc set) to fit the axle, no idea aout what the difference would have been.
scootchu: that's what 67m302 means, no tyre traction, no problem to lock them up. for example in rain I lock them up easily, in the dry I really have to stomp it and with the drums I felt I never got them locked, and if I did then only one side.
changed the rear as well to discs, but only because they were 50$ difference (new drum set, new disc set) to fit the axle, no idea aout what the difference would have been.
scootchu: that's what 67m302 means, no tyre traction, no problem to lock them up. for example in rain I lock them up easily, in the dry I really have to stomp it and with the drums I felt I never got them locked, and if I did then only one side.
Last edited by kalli; Feb 16, 2011 at 03:25 PM.
1st Gear Member
Joined: May 2009
Posts: 84
From: FL
I've owned a 66 coupe with drums all around (no power brakes) and my current 66 convertible with factory Kelsey-Hayes disc brakes up front and drums in the back (no power brakes). With both setups serviced properly, it isn't even close... the discs stop better AND more predictably (car doesn't pull to one side in a panic stop). My 66 coupe was waaaaaay too much of a thrill ride in a panic stop for this old man.
That being said, issues with either brake type can cause poor performance, but I wouldn't hesitate to upgrade to discs in the front on any old Mustang. While you're at it, replace your old brake lines and hoses and put in a dual-bowl M/C.
That being said, issues with either brake type can cause poor performance, but I wouldn't hesitate to upgrade to discs in the front on any old Mustang. While you're at it, replace your old brake lines and hoses and put in a dual-bowl M/C.
6th Gear Member
Joined: Oct 2006
Posts: 6,417
From: Cork, Ireland
well I used CSRP, which I am happy with. http://www.discbrakeswap.com
and there is as well chockostang who posts here on the forums as well http://www.chockostangclassicmustang.com/
and there is as well chockostang who posts here on the forums as well http://www.chockostangclassicmustang.com/
Last edited by kalli; Feb 17, 2011 at 05:51 AM.
Thread Starter
1st Gear Member
Joined: Aug 2010
Posts: 133
From: IL
You guys rock! Those are much less expensive than what I had found searching the net.
Okay, so one last question as brakes are new to me, (I'm more an engine guy, although I will most likely be asking questions on these as I haven't touched an engine this old before). How do I tell if I have power or manual brakes? I'm betting I have manual as it is a 200 C4, but always better to know than guess.
Okay, so one last question as brakes are new to me, (I'm more an engine guy, although I will most likely be asking questions on these as I haven't touched an engine this old before). How do I tell if I have power or manual brakes? I'm betting I have manual as it is a 200 C4, but always better to know than guess.
