Rotor sizes
| Diameter | Typical use |
|---|---|
| 140mm | Road rear, light riders |
| 160mm | Road front, gravel, XC rear |
| 180mm | Trail, gravel front, e-bikes |
| 200 / 203mm | Enduro, e-MTB, heavier riders |
| 220mm | Downhill and heavy e-MTB |
Bigger rotors give more leverage and run cooler. Check the maximum rotor size your fork and frame allow.
How the rotor fits the hub
| Mount | What it is |
|---|---|
| 6-bolt | Six Torx bolts. Very common |
| Centerlock | A splined fitting with a lockring. Common on Shimano hubs |
Adaptors let you fit a 6-bolt rotor to a Centerlock hub. You can't go the other way.
How the caliper fits the frame
| Mount | Found on |
|---|---|
| Flat mount | Most modern road and gravel bikes |
| Post mount | Most MTBs |
| IS (International Standard) | Older MTBs |
To go up a size, you'll usually need an adaptor that moves the caliper further out, for example a +20mm post mount adaptor to go from 160mm to 180mm.
When to replace a rotor
- It's worn below the minimum thickness stamped on it.
- It's warped and can't be trued.
- It's been contaminated and won't clean up.
FAQs
Can I use a bigger rotor on the front only?
Yes. That's common, as the front does most of the braking.
Do rotor brands matter?
Use a rotor that suits your pad compound and is compatible with your brake system.
What bolts should I use?
Use the bolts supplied, with threadlock if specified, and tighten to the torque in the instructions.