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Now Where Did I Leave Off?


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#1
cbstdscott

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Oh yeah, aluminum rear drums.

 

It is good to be back.

 

Scott


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#2
greasemonkeyreborne 5x1g's

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dizzy advance was it?

welcome back
Keepin' it OEM

#3
Sinub

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Locking the rear axle?



#4
Aren D.

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What is the actual hard data of the weight off an aluminium rear drum setup? IE backplate, drum, internals?

#5
cbstdscott

  • Swap in HF drums, check your cam timing
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The aluminum drums are lighter than the iron drums. The iron drums are lighter than the rear discs. Many years ago somebody tried to prove me wrong and install discs that were lighter than the aluminum drums. He ended up with go-kart brakes. Look it up on this site.


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#6
Aren D.

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Yes. Your logic is sound, so what's the weight, anyone actually know?

#7
cbstdscott

  • Swap in HF drums, check your cam timing
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Good question. It would require someone with nothing better to do and all the right bits to get the exact numbers.


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#8
CSPCRX

You don’t need to change the backing plates. I didn’t when I switched mine.


Victor
86 B-Powered CRX SI (SMF Solo2, HPDE-4 NASA & TA-A Time Attack

85 CRX DX totally original
07 Harley FXST Softail

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#9
Aren D.

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I found some numbers around the internet so nothing confirmed, the honda Insite aluminum drum is 4.75lbs for only the drum. The CRX Iron drum is 7.5lbs listed on rock auto.

Using this as a rough estimate for the crx is it safe to say the aluminum drums would drop 2.75bs per corner or drop 5.5lbs total?

#10
Aren D.

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For comparison just the disc of a 1989 Integra weighs 6.9 lbs. Just now weighed one.

#11
cbstdscott

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You have to include the weight of the caliper and the bracket to hold it for the rear discs. Let's assume at least one pound (but realistically it would be maybe closer to three pounds or more), it become apparent that the aluminum drums are the lightest choice.

 

For a car that has 60% of its weight over the front wheels at rest and far less under braking, you can see why the aluminum drums works so well.


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#12
Aren D.

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Yeah but I didn't include the backing plate/stuff or calipers/stuff because I didn't have any numbers.

The aluminum drums seem like a quick way to drop a few pounds and maintain OEM performance.

#13
kedwards

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You don’t need to change the backing plates. I didn’t when I switched mine.

In my experience, some backing plates don't "rub" on the aluminum drums, some do. Backing plates for cast iron drums have an inner "lip" that can be very thin (that bends and rusts) or they can be thick. The thick lip wouldn't allow the aluminum drum to turn, on one of my CRXs. The thin lip needed just a little straightening with needle nose pliers. And just a couple of miles of rubbing wore any remaining bends.


Keith A. Edwards
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1.75 1st gen. CRXs
former ECHC H5 Champion


#14
cbstdscott

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The 1988 and later Civic backing plates will accept the aluminum drums. That is what I am using on my '87 Si.


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#15
CSPCRX

In my experience, some backing plates don't "rub" on the aluminum drums, some do. Backing plates for cast iron drums have an inner "lip" that can be very thin (that bends and rusts) or they can be thick. The thick lip wouldn't allow the aluminum drum to turn, on one of my CRXs. The thin lip needed just a little straightening with needle nose pliers. And just a couple of miles of rubbing wore any remaining bends.

That is what I experienced as well. Straightened out the lip where there was dings and pushed it on. I did this years ago but I do recall on side sliding on more easily then the other. Then I turned it back and forth until it turned with less drag. Drove it a few miles pulled the drums off and they slide right on. Basically same experience as you had. In my opinion it was much easier than changing the backing plates.

 

i have never had much luck getting the parking brake cable out of them, even with the special tool that still doesn’t seem to work.


Victor
86 B-Powered CRX SI (SMF Solo2, HPDE-4 NASA & TA-A Time Attack

85 CRX DX totally original
07 Harley FXST Softail

2021 Tacoma Tow/Daily