Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

redpoint5 · 02-26-2012, 01:54 AM

I like to think about these types of questions like this:

Friction = energy lost to heat

Suppose I am loosing 1hp of energy due to friction. That means I am loosing 746 watts of power in the form of heat. That is a lot of heat! I can't imagine bearings that are in decent shape heating up by any significant amount. Certainly not anywhere near 1hp, which itself is a very modest amount of power.

The pads on disc brakes remain in contact with the rotor even when the brake pedal is released. This constant friction is so low as to be negligible because the force of the caliper is not pressing the pads against the rotor.

I'm sure a brake system could be designed that retracts the pad away from the rotor and eliminates friction altogether, but the tiny savings would not justify the added complexity.

Where am I going with all this; if it ain't getting hot then it ain't reducing your MPGs.

02-26-2012, 01:54 AM	#5 (permalink)
redpoint5 Human Environmentalist Join Date: Aug 2010 Location: Oregon Posts: 12,917 Acura TSX - '06 Acura TSX 90 day: 24.19 mpg (US) Lafawnda - CBR600 - '01 Honda CBR600 F4i 90 day: 47.32 mpg (US) Big Yeller - Dodge/Cummins - '98 Dodge Ram 2500 base 90 day: 21.82 mpg (US) Chevy ZR-2 - '03 Chevrolet S10 ZR2 90 day: 17.14 mpg (US) Model Y - '24 Tesla Y LR AWD Pacifica Hybrid - '21 Chrysler Pacifica Hybrid 90 day: 38.47 mpg (US) Thanks: 4,354 Thanked 4,502 Times in 3,463 Posts	I like to think about these types of questions like this: Friction = energy lost to heat Suppose I am loosing 1hp of energy due to friction. That means I am loosing 746 watts of power in the form of heat. That is a lot of heat! I can't imagine bearings that are in decent shape heating up by any significant amount. Certainly not anywhere near 1hp, which itself is a very modest amount of power. The pads on disc brakes remain in contact with the rotor even when the brake pedal is released. This constant friction is so low as to be negligible because the force of the caliper is not pressing the pads against the rotor. I'm sure a brake system could be designed that retracts the pad away from the rotor and eliminates friction altogether, but the tiny savings would not justify the added complexity. Where am I going with all this; if it ain't getting hot then it ain't reducing your MPGs. __________________ Gas and Electric Vehicle Cost of Ownership Calculator Give me absolute safety, or give me death! Last edited by redpoint5; 02-26-2012 at 02:05 AM..