Backing plates

[Hotwheels sr.]

I have a set of backing plates that had 10"x 1-3/4 shoes on them. I am upgrading the axle to lbp and I have to step up to 10x2-1/2 shoes. I thought I was told that I would have to change the backing plates to do that. Was just talking with someone selling 10" Backing plates. where i thought the issue was, the pin at the top the shoes ride/pivot on was longer for the 2-1/2. The ones he has measured the same as mine and his 11" measured the same as well. So, will my backing plates work for my upgrade or not?

 

[rrvolare]

I am doing the same change over .. i changed backing plates just in case ....

 

[hemi71x]

Backing plates are matched, to the size width, of the shoes.
It's the "depth" of the stamping to the backing plates, that make then unique to one another, in shoe sizes.
Used in matched pairs, plates, and shoes.

 

[Hotwheels sr.]

Backing plates are matched, to the size width, of the shoes.
It's the "depth" of the stamping to the backing plates, that make then unique to one another, in shoe sizes.
Used in matched pairs, plates, and shoes.

So let me see if I understand. It isn't necessarily that pin at the top it the depth of the plate where the shoes sit? Almost like any offset?

 

[brian6pac]

Go from the 3 pads that the shoe sets on to the center of the shoe, 1.75" shoe, .875" to center, 2.5" shoe, 1.25" to center, so 3/8" difference between the 2 shoes. the post will stick out further or the backing plate will be deeper where the shoe sets or a combination of both.
Bottom line is they are different! Very simple.
That's a couple minutes of my life I wont get back.

 

[Hotwheels sr.]

Go from the 3 pads that the shoe sets on to the center of the shoe, 1.75" shoe, .875" to center, 2.5" shoe, 1.25" to center, so 3/8" difference between the 2 shoes. the post will stick out further or the backing plate will be deeper where the shoe sets or a combination of both.
Bottom line is they are different! Very simple.
That's a couple minutes of my life I wont get back.

I apologize for using up your time. Please feel free to send me a bill. I do understand that there would be a dfference in the two. Just trying to figure out where the difference is when the person selling 10" plates doesn't know if they are 2-1/2 or 1-3/4 himself. Dont want to buy and end up with the same I already have. Thanks for your input.

 

[hemi71x]

There is a method in determining the "depth" of a backing plate by measuring from one point of the plate to another.
It's been discussed numerous times in the past, on this forum, and other Mopar related, car web sites.
But i personally have never bookmarked any of those threads, or postings, for personal use.
Why don't you use GOOGLE, and see what you come up with, on how to take measurements.
I'm sure something will show up.

 

[Hotwheels sr.]

There is a method in determining the "depth" of a backing plate by measuring from one point of the plate to another.
It's been discussed numerous times in the past, on this forum, and other Mopar related, car web sites.
But i personally have never bookmarked any of those threads, or postings, for personal use.
Why don't you use GOOGLE, and see what you come up with, on how to take measurements.
I'm sure something will show up.

I have used Google and such but really hadn't come up with much. Brian6pac actually spared a couple of minutes and got me to understand it. Thanks

 

[deviledchin]

Both backing plates are 10". Look at the pads where the brakes ride. The right one is LBP axle, 2 1/2" shoe. The left one is SBP axle, 1 3/4" shoe. From what I found, you cannot get a larger drum (wider) for a 4"(SBP) axle. Larger drums are only available for LBP axles.

 

[Hotwheels sr.]

Both backing plates are 10". Look at the pads where the brakes ride. The right one is LBP axle, 2 1/2" shoe. The left one is SBP axle, 1 3/4" shoe. From what I found, you cannot get a larger drum (wider) for a 4"(SBP) axle. Larger drums are only available for LBP axles.

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I love your samples, I appreciate it. My axle used to be sbp but I bought posi, rebuild kit and lbp axles fr Dr. Diff. Thank you.