Looks pretty slick, I wouldn't mind having that setup
I must say though, I can't believe that the rotational inertia of those big disks is less than the smaller ones. Weigh less - sure, but the weight was taken out of the place that matters least.
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What's a bolt on
Looks pretty slick, I wouldn't mind having that setup
I must say though, I can't believe that the rotational inertia of those big disks is less than the smaller ones. Weigh less - sure, but the weight was taken out of the place that matters least.
A 19lb disc that is 12" in diameter has a rotational inertia of 0.10008kg-m2
A 22lb disc that is 11.25" in diameter has a rotational inertia of 0.10185kg-m2
I didn't say it was a lot less, but it isn't more which is a great trade off for the better cooling/thermal mass capabilities.
Also, a lighter object takes less force to stop it so it won't generate as much heat...
What bore M/C are you using? We've had good results with 1" and no booster.
$540? Ouch! I have first hand experience with one off machining projects. Everything we make starts off with one off prototypes for testing and it sure can get expensive & time consuming. We are doing so much volume CNC work lately though that its cheaper and quicker to make the brackets billet than it is to make multiple pieces and weld them together. We should have stock of them early December.
Along with this kit I've also designed an aluminum hub for even more weight savings. Made from 7075 and hard anodized it weighs just 2.85lbs without races/studs. It is dimensionally the same as a drum hub in all the right areas so it'll work with this, or any of our other kits that use a seperate rotor/hub. I'll be testing them on my car next year. This should drop a few more pounds of unsprung weight.
It's an aluminum 1" bore master from Cobra Automotive. I've never been able to "connect
the dots" as far as its source but it's probably the master off the '85 Lincoln town car.
I don't use boosters on these cars, they have plenty of brake without them.
I like the aluminum hub concept. The cars I've got all have 65-67 cast iron hubs. I did it
that way because nothing else was available and it also looks stock.
I looked at ABS's re-do of the big K/H calipers as well, but the mounting ears bother me.
Not a lot of material there but lots of twisting stress. High Mu brake pads and a heavy
foot might shear those calipers right off the brackets......
I'd have to pop for a set and then test them before I was sure of their safety.
Not a lot of material there but lots of twisting stress. High Mu brake pads and a heavy
foot might shear those calipers right off the brackets......
I'd have to pop for a set and then test them before I was sure of their safety.
I would buy a set for testing if they ever had any... They advertise them in their catalog as being used on a bunch of kits they produce. I've never seen any kits and never heard of any breaking issues. That could be because there are not many out there because they never have any!
Oh well, they are not vintage legal so I'm not going to worry about it to much. I could see how a guy building a T/A replica for open track or street cruising could be interested but all of this is mute if the mounting ears snap off!
Regarding the disk brake hub, does that have the same rotor mounting offset as a drum hub? It would be the distance from the inner wheel race stop to the front side of the rotor mounting plane I'd need to compare. The drum brake hub is 1.05". I've only ever used drum brake hubs so all my brackets are built around that offset. I don't have any disc brake hubs to measure. Anybody?
Up till last Wednesday (now unemployed) I worked in Orange and ABS was about 2 miles
away. I actually went over there in June or July and checked out the caliper. They only
had the two halves, nothing assembled. They were light! Even with the two big bridge bolts,
pistons, seals, pads and a transfer tube, they would have been considerably less than
the 65/66 Mustang cast iron unit. The story was that they were "sold out."
Maeco doesn't have any on their customer's cars bec I talked to Mike about them at the
time. He was also questioning the strength of materials in the mounting area.
Don't have a loose disc hub. My memory of them is that the offset distance is different
from the drum hubs. The disc hubs have become nearly "unobtainium." So much so that
until I found a pair by shear luck, I was going to pop for two brand new units from Virginia
Classic Mustang. (Wagner or someone is apparently making the two piece style again)
A 19lb disc that is 12" in diameter has a rotational inertia of 0.10008kg-m2
A 22lb disc that is 11.25" in diameter has a rotational inertia of 0.10185kg-m2
I didn't say it was a lot less, but it isn't more which is a great trade off for the better cooling/thermal mass capabilities.
If you are using constant density cylindrical cross sections, that method of analysis is almost completely irrelevant.
The areas further from the center are both heavier and have a greater distance from the rotation axis (on the new disk). The hub, which is very near to the center of the wheel, is the part that lost weight.
It's like taking a big bomb away from South Korea, making it 3 pounds smaller, and giving it to North Korea. (sorry, that's the best analogy I could come up with).
The only way I know how to test this is to mount a rotor on a hub, and hang a weight on a string off the side of the rotor at 10" from the ground, let it fall, see how fast the rotor spins, and then rinse and repeat with the other rotor, and see which spins faster. You would have to hang the weight at the same radius, though.
Quote:
Also, a lighter object takes less force to stop it so it won't generate as much heat...
3 pounds off a 2,500+ pound car is not going to produce a change in heat that could be measured...
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If you are using constant density cylindrical cross sections..
Well yes, I was simplifying it and using disc rotation inertia. To be 100% accurate I'd have to chop off the 'hat' portion of the 70 rotor I'm comparing the 12" 2-pc to and calculate its mass. Then, calculate using the inner and outer diameters of the hat, rotor and their individual masses.
The 12" 2-pc rotor is farily easy, I just un-bolt the hat, measure and weigh. I'm not about to chuck a 70 rotor in a lathe and chop off the friction surface just to weigh it.
That being said, if the 70 rotors hat is 8" wide and so is the aluminum hat, the aluminum one is lighter so will lessen its total rotational inertia.
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Originally Posted by TheShagg
3 pounds off a 2,500+ pound car is not going to produce a change in heat that could be measured...
6lbs, 3 each side. I'm pretty sure it could be measured. What you mean is will it be noticed? Probably not on a street car. You'd have to be going at a good clip to overheat these even on a road course.
Although Mike offered to make me some out of billet, I had a tighter schedule - most of Maeco's brackets are done on an endmill, a lathe and are tig welded. I have a pair from Speed Parts International (when they offered them in the 90's) on my race car that were actually patterned off Follmer's car and CNC'd. They were $540 for the pair.
The Maeco ones are almost as nice looking and nowhere near as expensive.
Maeco is now making the billet brackets. I bought one of their first sets for my track project. They are very nice pieces.
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'66 GT Coupe
'65 Fastback Project
For sure, I think this is a great upgrade for many reasons. I just don't think that rotational inertia got better but I do agree that it is better than it would have been had you not used the aluminum hat.
I'm nit picking! Can't a man nit-pick a little?
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What's a bolt on
For sure, I think this is a great upgrade for many reasons. I just don't think that rotational inertia got better but I do agree that it is better than it would have been had you not used the aluminum hat.
I'm nit picking! Can't a man nit-pick a little?
I fully appreciate ALL nit picking! Helps me build a better product.
Has anyone come up with a way to mount the big calipers without having to drill out the threads in them? I have most of the parts and several sets of used calipers, but I don't wan't to have to make the caliper unuseable for all but my application.
Has anyone come up with a way to mount the big calipers without having to drill out the threads in them? I have most of the parts and several sets of used calipers, but I don't wan't to have to make the caliper unuseable for all but my application.
I wouldn't worry about it. There are plenty of Mustang guys using those calipers with the threads drilled out. I don't think you'll be narrowing your market by much (eliminating stock 67 Tbird guys) if you did drill them and then needed to sell them.
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but I do agree that it is better than it would have been had you not used the aluminum hat. 
