• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

stopping power 10.95 rotors vs 11.75 rotors ?

R

rustytoolss

Well-Known Member
Local time
7:37 AM
Joined
Mar 4, 2018
Messages
507
Reaction score
134
Location
New Franklin, Ohio
I have the 10.95 rotors and 2.75" calipers right now. If I were to get the larger 11.75 rotors , how much more stopping power should I expect to see ? I also have 10" rear drums...this is a manual brake car.
 
Not necessarily any on a normal stop. The larger rotors will absorb more heat so they would be more resistant to brake fade under repeated hard stops. Depends also on the condition of the rest of the braking system and how much the rear brakes are adjusted as well as tires and air pressure. All effect braking.
 
My vote would be for the bigger rotors. I have a 71 Cuda with a gen 2 hemi which has put some extra heft on my front end. Prior to the Hemi I had 440 up there motivating the car. I don't race, but I have had to make some panic stops driving here in NY. I have never had the rotors fade or warp on me causing brake shudder. The larger rotors were standard on 75 and up Cordoba's giving them plenty of stopping power. To be truthful I have never had a problem with Mopar brakes, and some other cars front disc's have been a problem on a regular basis.
 
rustytoolss said:
I have the 10.95 rotors and 2.75" calipers right now. If I were to get the larger 11.75 rotors , how much more stopping power should I expect to see ? I also have 10" rear drums...this is a manual brake car.
Click to expand...

It's all about the leverage - the farther away from the center the greater stopping power
 
FYI, you will also need the caliper mount for the larger diameter rotors (and 15 inch wheels). The mounts are different between the two rotor sizes.
I'm with ChargerST, it's all about the leverage
 
Keep in mind that that will increase the brake bias which will require a proportioning valve to manually adjust. I think you're opening a can of worms.
 
The larger 11.75 rotor has 1/3 more surface area then the 10.95 rotor. The 11.75 rotor can absorb more thermal energy then the 10.95 rotor will and you get around 20-25 percent more stopping power. You will notice the difference!
Frictional clamping force from the caliper can only practically be increased so much so as to not dramatically increase rotor wear and pad wear. A larger rotor can more easily stop the car than a smaller rotor given the *same* frictional surface area *and* clamping force. A simple analogy turn you ceiling fan on high - get it going good and fast - then try stopping it by using your hand as close to the motor as you can and time how long it takes. Next, with you remaining working hand start the fan again and try stopping it from the edge of the fan blade. Note the difference and ease of performing it from the edge.
This is why they installed the 11.75 rotor on the C body cars back in the late 60s, 440 + big heavy car, makes for a hard time stopping.
 
moes said:
The larger 11.75 rotor has 1/3 more surface area then the 10.95 rotor. The 11.75 rotor can absorb more thermal energy then the 10.95 rotor will and you get around 20-25 percent more stopping power. You will notice the difference!
Frictional clamping force from the caliper can only practically be increased so much so as to not dramatically increase rotor wear and pad wear. A larger rotor can more easily stop the car than a smaller rotor given the *same* frictional surface area *and* clamping force. A simple analogy turn you ceiling fan on high - get it going good and fast - then try stopping it by using your hand as close to the motor as you can and time how long it takes. Next, with you remaining working hand start the fan again and try stopping it from the edge of the fan blade. Note the difference and ease of performing it from the edge.
This is why they installed the 11.75 rotor on the C body cars back in the late 60s, 440 + big heavy car, makes for a hard time stopping.
Click to expand...
As far as up front weight, My 318 poly weighs in at over 600 LBS, I just installed a 15/16 MC and am not getting the stopping power I want. Have only driven the car once around the neighborhood. Don't think it could slide the tires. I still need to do so more things (rebleed for possible air/ check rear brakes for adjustment, play with my adjustable rear pressure valve) The car does stop better, but still think that more can/should be done.
 
I didn't notice a huge difference.....until I added rear 8.25 disc from a 97 Grand Cherokee and prop valve. I did not have to swap the m/c. Wish I had manual brakes though. With that said I would still go with the 11.75's on the front.
 
The thing that seems to be left out of a lot of brake discussions are pad compounds.
There are lots of choices out there and they can make a HUGE difference in pedal pressure
and "feel".
Higher cf materials will come at a price....more wear, dust, usually less life. For cars not
driven many miles maybe a good choice.
 
Dave P, cf materials? What does that refer to?
 
Dave P said:
The thing that seems to be left out of a lot of brake discussions are pad compounds.
There are lots of choices out there and they can make a HUGE difference in pedal pressure
and "feel".
Higher cf materials will come at a price....more wear, dust, usually less life. For cars not
driven many miles maybe a good choice.
Click to expand...
Also, new pads/shoes don't grab as well until they are used a bit.
 
Demonic said:
:rofl:


I swapped to the larger rotors on my 69 Charger, it made a difference.
Click to expand...
Well it lookks like I may need to do that , Thanks
Dave P said:
The thing that seems to be left out of a lot of brake discussions are pad compounds.
There are lots of choices out there and they can make a HUGE difference in pedal pressure
and "feel".
Higher cf materials will come at a price....more wear, dust, usually less life. For cars not
driven many miles maybe a good choice.
Click to expand...
Long ago I looked into pad compound material. As I recall FF (organic) had the most bite then FE, but short pad life. Don't know if you can still get organic pads.
 
Dave P said:
The thing that seems to be left out of a lot of brake discussions are pad compounds.
There are lots of choices out there and they can make a HUGE difference in pedal pressure
and "feel".
Higher cf materials will come at a price....more wear, dust, usually less life. For cars not
driven many miles maybe a good choice.
Click to expand...
What brake pad meterial would you think would provide the best " feel for pressure and stopping power" don't care about pad life. only drive 1-2 thousand miles a year if that.
 
I'm fairly well convinced that "proportioning" was done with wheel cylinder/caliper piston bore size.

If you also put rear wheel cylinders from an 11.75" disk car on the back, you should be good to go.
 
moes said:
The larger 11.75 rotor has 1/3 more surface area then the 10.95 rotor. The 11.75 rotor can absorb more thermal energy then the 10.95 rotor will and you get around 20-25 percent more stopping power. You will notice the difference!
Frictional clamping force from the caliper can only practically be increased so much so as to not dramatically increase rotor wear and pad wear. A larger rotor can more easily stop the car than a smaller rotor given the *same* frictional surface area *and* clamping force. A simple analogy turn you ceiling fan on high - get it going good and fast - then try stopping it by using your hand as close to the motor as you can and time how long it takes. Next, with you remaining working hand start the fan again and try stopping it from the edge of the fan blade. Note the difference and ease of performing it from the edge.
This is why they installed the 11.75 rotor on the C body cars back in the late 60s, 440 + big heavy car, makes for a hard time stopping.
Click to expand...

EXCELLENT RESPONSE.....factual and to the point....or "bigger is always better" so to speak....
BOB RENTON
 
Sorry for the late return to this thread.
What I meant by cf was coefficient of friction, most, maybe all race pad manufactures provide grafts or curves
showing friction response at different temperatures of the pad material.
I don't know street brakes enough to point to something specific. In general, EBC for example, makes
several street usable compounds. Often times it's worth making phone calls to the company's tech
support for some ideas.
Dave
 
The bottom line is that the bigger Rotors are well worth the investment for better stopping power and longevity. But it was mentioned that you will need the caliper adapter for the bigger rotors. I got mine, the adapter, from a Cordoba when I converted to Discs up front. I order Cordoba rotors when I need a replacement. And order the dust cap for those rotors because it's an unusual size, Dorman 13996.
 
You must log in or register to reply here.

Similar threads

67Goldie
Disc brake conversion help
Replies
12
Views
1K
66Belv440
66Belv440
Splangj
Four vs. six piston
Replies
7
Views
779
Splangj
Splangj
Jimclo2002
70 super bee brake problems
Replies
16
Views
2K
Dartman72
D
Kern Dog
Free play in power brake systems.
2 3
Replies
49
Views
3K
66 Sat
66 Sat
Road Grabber
Need Brake Expertise to Identify Rotors
2 3
Replies
41
Views
4K
JG71B
JG71B
Auto Transport Service
Back
Top