Disc brake rotor sizes vary, with some measuring 160, 185 or 203 mm. Other rotors are sold at 6”, 8” or other sizes. The brake dimensions used varies per vehicle. Generally, the larger the rotor, the less pressure is required to put on the brakes. The smaller the rotor, the more pressure is needed.
Rotors come in two variants. The first is the vented type where two plates are melded with the cooling vents sandwiched between them. These are designed for front disc brakes. However these can also be applied on the back of large vehicles (only those with four wheel brakes).
The second rotor type is the solid or single plate rotor. These are applied on rear disc brakes. Their application is for small vehicles only.
When Rotors Need to be Replaced
It isn’t the brake rotor size that determines its lifespan, but rather the geography and the weather. Generally speaking, rotors not exposed to intense winter conditions will last longer. Roads that have corrosive salt and / or sand will also reduce the lifespan of rotors.
The time needed to replace a rotor will vary, but the rule of thumb is that when the pads have to be replaced, new rotors should be installed.
How to Replace Rotors in a Truck
- Torque wrench
- SAE wrench set
- SAE socket set
- Allen wrench set
- Breaker bar
- Lug wrench
- Jack stands
Raise the truck’s front using the jack and remove the front tires.
Find the two nuts at the brake caliper’s back. Unfasten the bolts with the Allen wrench. Use a wire to support the caliper. Remove the two bolts located at the steering knuckle’s back side.
Slide off the rotor carefully from the wheel studs. Place it aside. Get the new rotor and slide it into place.
Put back the mounting bracket and the brake. Use the socket and torque wrench to fasten the bolts.
Put the brake caliper back in the mounting bracket. Put the two bolts back in. Tighten the bolts.
Install the tires and wheels. Don’t forget to thread the lug in the wheel studs. You have to torque the lugs based on the manufacturer specs. Remove the jack. Make sure to test the vehicle before you drive too far.
Note that you cannot just get a larger disc brake rotor size for your vehicle. Consult the user manual first. It may require a specific type of rotor.