Last post on May 03, 2013 at 4:53 PM
You are in the Maintenance & Repair
What is this discussion about?
#1978 of 2025 Re: Why is is...? [shipo]
Dec 02, 2010 (3:36 pm)
Ah...O.K...whatever floats your boat I suppose.
As far as I'm concerned, it the rotors are within specs thay are good to go.
But then, I don't drive our cars hard.
Some European cars such as BMW's will wear out a set of rotors every time they need pads.
#1979 of 2025 Re: Why is is...? [isellhondas]
Dec 02, 2010 (4:07 pm)
And that's what I like to drive. That said, pretty much every car I've owned or maintained over the last twenty or thirty years has not been kind to its rotors, my BMWs included.
#1980 of 2025 Re: Why is is...? [shipo]
Dec 03, 2010 (7:11 am)
OK, that explains things. Nothing can outstop a BMW but they do eat rotors.
#1981 of 2025 Re: Why is is...? [isellhondas]
by Mr_Shiftright HOST
Dec 03, 2010 (9:11 am)
You know, if that's the price I have to pay to stop in 95 feet instead of 100 when I'm 98 feet behind a flatbed truck, I'll pay it.
#1982 of 2025 Re: Why is is...? [Mr_Shiftright]
Dec 03, 2010 (9:25 am)
I worry more about the semi behind me needing 200 ft to stop .
#1983 of 2025 Re: Why is is...? [srs_49]
by Mr_Shiftright HOST
Dec 03, 2010 (9:42 am)
Alas, there are some things in our control, and some out of them.
#1984 of 2025 Re: Why is is...? [Mr_Shiftright]
Dec 03, 2010 (11:50 am)
I understand and I agree but if the old rotors were well within spec I don't see how a replacement rotor could stop you any faster.
#1985 of 2025 Re: Why is is...? [isellhondas]
Dec 03, 2010 (9:49 pm)
Simple physics; the thicker the rotor the greater the thermal mass, the greater the thermal mass the better the stopping power. Why? Because the rotor stays cooler during a high energy stop. While a worn rotor may still be "in spec", that in no way means that it's able to sustain stopping power as great as it could when it was thicker.
#1986 of 2025 Re: Why is is...? [shipo]
Dec 04, 2010 (6:55 am)
the thicker the rotor the greater the thermal mass, the greater the thermal mass the better the stopping power. Why? Because the rotor stays cooler during a high energy stop
We're talking very little thermal mass here from a machined rotor to a non-machined. Hot rodders spin their rubber tires to generate heat for better road contact, so I don't see how a slightly cooler /slightly heavier rotor will stop a car quicker. It would be like spitting in the ocean and trying to measure the rise in sea level.
#1987 of 2025 Re: Why is is...? [jipster]
Dec 04, 2010 (7:28 am)
>so I don't see how a slightly cooler /slightly heavier rotor will stop a car quicker.
I do not know that the tenet is that a thicker rotor will stop the car quicker. What it will do is stay slightly cooler as the predetermined quantity of heat is transferred into it. Staying slightly cooler may mean better braking, but in my thinking it means the rotor is slightly less likely to suffer distortion at the end of the stop due to the extreme heating during a hard stop or a long braking period such as a long downhill run.
But I have another observation. That is that the inside fins of most rotors are covered with a rust material. That has to insulate an old rotor from the air going through the fins and somewhat lower the transfer of heat to the air through those openings. That's why if I drive a car hard or I have had brakes that warped slighty I feel it's time for a quality new rotor that has a cleaner surface on the fins with which to transfer heat to the air that's interior to the rotor as well as the external surface air. If it's my 180,000 mile Buick that's driven mostly gently around the suburban and rural region, I think less about new rotors.