Noticable difference from 10" to 11" rear drums?

[miller]

I am going to be upgrading my rear end from 8 1/4 to 8 3/4. I want to know if I should redo the brakes that the 8 3/4 came with ( 11" drums) or if I should keep the brakes from the 8 1/4 (10" drums).


Also do 11" drums mean I need 15" wheels?

[b5blue]

Disk brake cars came with 10in. drums you should be fine, I don't think 15in. rims are needed for 11in. drums. 

[Mr_fixit]

You would be better to go with bigger discs on the front than 11" drums on the rear.  That 's the important end that stops.  That would require 15" wheels, though.

[Chatt69chgr]

I think the 10 inch brakes from the 8-1/4 will bolt right up to the 8-3/4.  So you could use either one.  From what I have read, the cars with front discs came with 10 inch rear drums.  The cars with 11 inch drums on the front came with 11 inch drums on the rear.  The parts will probably cost the same for each.  Not sure what front brakes you have now or what year your car is.  The correct porportioning valves and hold off valves are now available from In-Line Tube.  In any case, you will probably want to install a adjustable proportioning valve in the line going to the rear to allow you to properly set the line pressure to the rear.

[b5blue]

Also you could run 14's if you go with the smaller 10 inch rotor set up.

[miller]

Also you could run 14's if you go with the smaller 10 inch rotor set up.

Is there a way to buy front discs with 10" rotors? If so that would be fantastic, finaly get disc brakes and able to keep my 14" Magnum 500s.

[b5blue]

Yea you use the Factory Dart set up...Have you checked out the MoPar Action Disco Tech article in the online archives?  I've got a set of those (10.84 I think) caliper adapters (slider type) laying around here somewhere (I'm going with 11 3/4 rotors) Look at the info in the article first, MP Brakes sells all that stuff new I think.

[Chatt69chgr]

The caliper adapters for the 10.87 inch rotors are very common in junkyards.  I'am speaking of the sliders which is what you want anyway since good pads from Bendix are (or at least were) currently available for those unlike the pin type.  What is hard to find is the 11.75 inch caliper adapters slider type.  With all the new pieces coming out I wouldn't be surprised if someone doesn't offer aftermarket caliper adapters now for both sizes.  Also, these show up on EBAY frequently.

[b5blue]

That was my point, if he got spindles new and wanted to keep 14 in.rims, he could have the smaller caliper adapters off my spindles because I've got the 11 3/4 set-up.

[Mike DC]

 
About the 10-11" drums again -

If you're running around town in a street car that's gonna dive forward in a big way if you actually slammed the brakes hard, then the rear brake power is not very vital.  Bigger rear brakes only start to matter very much when you're cruising at 100mph and the chassis is so stiff that the weight is never gonna shift forward much no matter how hard to hit the pedal.



   

[C500]

SSBC does a disc brake conversion kit that you can use with 14 inch wheels. You keep your old spindles on too.

[bordin34]

There really is no need for 11" rear drums if you have discs up front already. With my stock disc brakes up front and 10" drums in the rear, I can lock up the rears going about 60mph.

[pettybird]

Also do 11" drums mean I need 15" wheels?

11" drums fit under 14" wheels.  we have more than a few cars here at the shop with this setup.  remember that all 1-2gen chargers came with 14" wheels standard, and R/T's came with 11" brakes...