have a problem with the front brakes on my 2008 Chevrolet Silverado
getting really hot. The truck is lowered and has large aftermarket
wheels. The truck has 42,000 miles on it and I put about 70 miles of
city driving on it a week.
The other day
I came home and took the temps of all four tires, wheels and brakes.
The low-profile tire road surface temps were 114 degrees average
with the front rotors at 300 degrees and the drum brakes in the back
at 98 degrees. The front wheel spokes were warm to the touch with
the area just under the tire reading between 100-120 degrees and at
the center hub about 130 degrees. Even when Iíve put the stock
tires and wheels back on I seem to be getting the same symptoms,
including the warm wheels.
brakes fine ó no spongy feel or hard-to-brake issues. The steering
wheel doesnít shake or wobble when I brake either. How do I
determine whatís causing the rotors and wheels to get so hot?
Emilio, Iím assuming you may have used an infrared temperature gun
to take these measurements. These are very cool gadgets and provide
some interesting and useful insight to various vehicle functions. I
use one also to check my trailer brake, bearing hubs and
miscellaneous temperatures while on the road. Iíve found
inoperative brakes, a dry U-joint and a binding/overheating brake. I
hope not to see bearing hub temperatures much more than youíve
a vehicleís kinetic energy to heat. It is possible, if you know
the weight of your brake rotors, to roughly calculate their
temperature increase from a single stop, at a certain speed.
Multiple stops greatly complicate this exercise.
In your case,
Iím not sure 300 degrees is such a bad thing for the brake rotor
surface after perhaps many starts and stops in city driving. Itís
best if brake rotor temperature doesnít rise too much past this,
but under very demanding conditions, rotor temperature can rise to
double or even triple this value. Iíd be curious to see what
temperature you find after driving for a moderate distance without
any stops ó perhaps 30 minutes of freeway driving and a gentle
coast to a stop. Temperature of the rotor face above
approximately125 degrees indicates the need for diagnosis. With this
number as a baseline, Iíd check temperature of both rotors after a
single firm stop from 60 mph and see if you are in the ballpark of
an on-line brake temperature calculator. Multiple stops would
increase temperature quite a bit as there isnít sufficient time
between for cool-down.
I pondered the
possibilities of lowered suspension and kinking of brake hoses;
larger tires; a binding caliper; and other braking issues that could
increase temperature. If both front brakes are very similar in
temperature and the stock tires provide similar operating results,
that rules out most of these possibilities. You mentioned also that
you havenít encountered any obvious brake pulsation, noise, or
spongy operation. How does the rotor finish look? Overheated rotors
often develop hard spots, which appear as off-colored spots.
If your brakes
arenít dragging, causing high temperature during non-use driving,
the temperature you are seeing may be attributable to the usage