brake rotor size question - from chat - StevenJay

Suspension, brake, and hydraulic/electric steering discussion.
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Navy Lifer
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Joined: Tue Mar 19, 2013 6:30 pm
Location: Canton GA

brake rotor size question - from chat - StevenJay

Post by Navy Lifer »

Steven,

Noticed you were on chat here and brought up question of rotor size.

"StevenJay • 23 Dec 2018 01:19
Looking at your post about rotor sizes doesnt look right...front rotors are always larger than rear"


"StevenJay • 23 Dec 2018 01:16
This is from a 2014 but they didnt change sizes: Front rotor: 321mm diameter Rear rotor: 315mm diameter"
- not sure I understand this comment

I do understand what seems to be an anomaly, however your statement is not accurate. There are a number of vehicles with larger rear rotors than on front.

Just to name a couple - Gen5 Camaro SS had a 355mm front (same as SS sedan Brembo brakes) and the rear rotor is 365mm. This is also true for Cadillac CTS-V (first gen). I can name others.

The thing to understand is that the engineers consider this sizing from the standpoint of wheel selection with the brake package, as well as caliper piston sizing, pad area, clamping radius, etc., to produce the desired system braking force at each end of the vehicle. Rotors serve as heat energy absorbers & radiators. Rear rotors may be larger in diameter, however in virtually every case they are also thinner, so that total rotor mass is less at the rear, which is consistent with the total amount of energy from heat that brakes generate, front vs rear, typically about 70% front, 30% rear.

Just wanted to add some background on this for you to consider.
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