D60/D70 Brake Swap Disc/Drum Weight Data

J.C.

J.C.

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Getting a set of D60F/D70R axles ready to swap into my truck I decided to do a little comparison while I have them apart. After reading all the info on the web about rear disc swaps to replace the HEAVY drum brakes I was suprised at my findings! The hub, rotor, caliper bracket, caliper and pads from one side of the D60F I have weighed 70 lbs. The hub, drum and backing plate with all shoes/hold down hardware from one side of the D70R weighed 62 lbs! Not a huge difference but I was expecting the rear to be quite a bit heavier, not lighter! I wonder if all those performing disc swaps have actually weighed the parts or just assumed those huge drums would be heavier. Could be that my scientific procedures are off too but it was a genuine Eckerd Digital scale :) I would welcome feedback from anyone that has actually checked on the weight differences between similar disc and drum setups.
 
I had heard something similar before too, but actually not that the drums were lighter!

OTOH, are you using 14" discs and calipers from a F550? :D
 
Ding, light comes on for mentally challenged retiree (old fart). It's not so much the total weight, though that is a concern, but the rotating weight that the disc swap will save. The D70R drum weighs six more lbs than the D60F rotor. Still not as much as I would have thought and I'm still not sure that 12 lbs more of rotating weight is worth the trouble and expense of a disc swap even given that the disc brakes probably work better overall than drums. Feedback appreciated.
 
CYJKrawler said:
It's not so much the total weight, though that is a concern, but the rotating weight that the disc swap will save. The D70R drum weighs six more lbs than the D60F rotor. Still not as much as I would have thought and I'm still not sure that 12 lbs more of rotating weight is worth the trouble and expense of a disc swap even given that the disc brakes probably work better overall than drums. Feedback appreciated.
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Exactly.. I doubt that matters at all, when you consider that it's attached to a 150+ lb tire and wheel combo. Sure on a road car, it matters (hence 2-piece rotors, aluminum calipers, etc...)

My biggest reasons for wanting discs:

MUCH easier to work on
Don't get clogged with mud
less moving parts
easier to clean

Downsides:
parking brakes are most expensive/more difficult to work in.. (not always an issue)
 
Rich said:
OTOH, are you using 14" discs and calipers from a F550? :D
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Nope, stock Dodge W300 1 ton 12.75" discs and calipers. But we could probably skew the data real good using the F550 stuff for a disc swap on a drum D35 :) Maybe I should look into swapping D30 discs on the D70R :)
 
Dang! I just swapped new hubs and axle shafts into my 14 bolt Saturday afternoon. I wish I would have measured the weight of the parts. The rotors I used sure felt more than 6 lbs lighter than the drums.
 
It depends on the setup. Back when I put discs on my 14 bolt, I found that the discs worked out to about 35# per side, and the drums were about 50# per side. That's not counting the hubs themselves, just the brake hardware. I was thinking the same things... 15# per side? I could make that up with a different tire/wheel combo.

But then I weighed the BIG 14 bolt drums, the drums alone were something like 60# each. So it makes a huge difference in certain applications.

You do lose rotating mass, so that might be worth something to you. Discs also work a hell of a lot better. And if you really want to save weight, there are much better options than OEM D60 parts.
 
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