Can I identify front disk rotor size without rotor removal? 1972 SSP

[Myasylum]

Rather than removing my front rotor is there a way to identify its size?

I have a 1972 Satellite SSP with a 400.

Seems just to make life complicated, it came with 2 different size front rotors. I'd rather not remove the bearings and all that just to measure the rotor size.

I have measured the rear drums to 11.5" is there a standard front rotor size to match the rear drums?

Thanks!

 

[1 Wild R/T]

If they are original the only option is 10.87.... And the rear drums aren't 11.5 you measure across the shoes or the shoe contact area of the drum... Your OE options are 10" or 11"

 

[4mulas]

Not sure why you have to remove bearings to measure a rotor, just take the wheel off and measure the diameter?

 

[Cranky]

Rather than removing my front rotor is there a way to identify its size?

I have a 1972 Satellite SSP with a 400.

Seems just to make life complicated, it came with 2 different size front rotors. I'd rather not remove the bearings and all that just to measure the rotor size.

I have measured the rear drums to 11.5" is there a standard front rotor size to match the rear drums?

Thanks!

The best way to measure a drum is to measure the ID of it but if you measure the OD, a 11" drum will most likely measure 11.5 or so....but I've never had a factory disc brake car that came with 11's on the rear.

 

[Myasylum]

The cap is in the way. Its hard to get an accurate measurement without taking off the rotor and measuring from the back.

 

[1 Wild R/T]

The best way to measure a drum is to measure the ID of it but if you measure the OD, a 11" drum will most likely measure 11.5 or so....but I've never had a factory disc brake car that came with 11's on the rear.

Actually a 11" drum on the outside measures about 12.5 think about how thick the edge is...Times two....

 

[1 Wild R/T]

The cap is in the way. Its hard to get an accurate measurement without taking off the rotor and measuring from the back.

View attachment 1501054

Post an actual picture of your rotor...

 

[Myasylum]

I'm at work. Yes 11.5 was the whole diameter from the outside edge. So if 12.5 is an 11" drum then 11.5 would make sense it's a 10" drum.
I did take these pictures last night of the markings on the drum.

 

[Cranky]

Actually a 11" drum on the outside measures about 12.5 think about how thick the edge is...Times two....

View attachment 1501056

Don't measure it there........kinda hard to measure it across that section with it on the car anyways.

 

[Cranky]

I'm at work. Yes 11.5 was the whole diameter from the outside edge. So if 12.5 is an 11" drum then 11.5 would make sense it's a 10" drum.
I did take these pictures last night of the markings on the drum.

View attachment 1501059

View attachment 1501060

Max diameter is 10.090.....on the ID where the shoes make contact. I've taken them to 10.125 over before though.

 

[Myasylum]

Well, if it states."10.090 Max Diameter" Wouldn't that make it 10" drums?

Still... Trying to figure out the size of the front disk though. I'd hate to have to remove them just to put them back on just for a measurement. But I guess I may have to?
Also 73's had a different size spindle which I guess there are bearing kits to use 73+ rotors on earlier model cars. Not sure why you'd do that but seems like people do.

 

[1 Wild R/T]

As I mentioned before stock would be 10.87 and if the car came with discs in the front the rear brakes would be 10" drums.. You have 10" drums so that fits... FWIW most call the 10.87 rotor an 11" rotor...

 

[Cranky]

Well, if it states."10.090 Max Diameter" Wouldn't that make it 10" drums?

Still... Trying to figure out the size of the front disk though. I'd hate to have to remove them just to put them back on just for a measurement. But I guess I may have to?
Also 73's had a different size spindle which I guess there are bearing kits to use 73+ rotors on earlier model cars. Not sure why you'd do that but seems like people do.

Yup, 10" drums.....like I said before, got to measure a drum by measuring the I.D. of it (Inside Diameter). For the rotor, take a piece of cardboard and cut out a section of it. Other words, make the cardboard look like a 'C' and make it fit the rotor then measure the opening with a ruler or tape measure.

 

[R/T Boy 67]

Measure the distance from the hub to the edge of the rotor, multiply times two then add the hub diameter to that. It doesn't have to be exact, it is either slightly less than 11" or 11 3/4". As stated the original ones would be the smaller size, but some one could have changed to the larger system.

 

[khryslerkid]

The cap is in the way. Its hard to get an accurate measurement without taking off the rotor and measuring from the back.

View attachment 1501054

 

[khryslerkid]

In other words measure the circumference and divide it by 3.14

 

[66 Sat]

Or put a straightedge out from the top of the rotor in line with the hub, and measure down to the center. Then x2.
This is not a difficult problem to overcome.

 

[1 Wild R/T]

What is this black magic???

 

[moparmarks]

Disc brake cars came standard with 10" drums. Wagons got 11" drums.