A disc rotor only fits a hub that uses the same interface. The two common interfaces are 6-bolt, where six bolts hold the rotor, and Center Lock, where the rotor slides onto splines and a lockring holds it in place. Park Tool says a 6-bolt rotor can be adapted to a Center Lock hub, but a Center Lock rotor cannot be adapted to a 6-bolt hub.
What fits what
| Hub | 6-bolt rotor | Center Lock rotor |
|---|---|---|
| 6-bolt hub | Fits directly | Cannot be adapted |
| Center Lock hub | Fits with an adapter kit made for the purpose | Fits directly |
Check the hub before you order a rotor or a wheel. Rotor diameter is a separate question: Park Tool lists 140, 160, 180 and 203 mm as the four main sizes, and generally recommends a like-for-like diameter when you replace a rotor. For sizes and caliper mounts, see disc brake rotor sizes and mounting standards; this page covers only the interface.
How each interface holds the rotor
6-bolt
The rotor lines up with the mounting holes in the hub and is fastened with six bolts. Park Tool’s tool list for the job is an appropriate wrench, usually T25 Torx compatible, a torque wrench with a matching bit, and threadlocker (TLR-1) for bolts that do not come with any. Park Tool has you work in a star pattern, hopping to every other bolt each time, while SRAM says to take one turn at a time in an alternating sequence.
Do not oil or grease the bolts, because of the contamination risk covered below. Threadlocker is a separate step: check new bolts for threadlocker that is already on them. If there is none, Park Tool says thread prep such as TLR-1 can go inside the hub’s rotor mounting holes, a single drop with the excess wiped away. SRAM specifies new, threadlock-prepped bolts.
Center Lock
The rotor goes onto the hub splines, tapered side first in SRAM’s instructions, and a lockring threads into the hub over it. Lockrings come in two styles that need different tools:
| Lockring style | How to recognize it | Tool Park Tool names |
|---|---|---|
| External notches | Notches on the outside of the ring | BBT-9, BBT-69.4 or similar |
| Internal splines | Notches on the inside, none on the outside | FR-5.2 family |
Other makers name their own tools. SRAM’s lockring takes a Ø44 mm 16-notch external bottom bracket tool, and Shimano’s June 2023 torque chart pairs its rotor lockring with a TL-LR15 tool and an adjustable wrench. Find out which style you have before you buy a tool.
There is one known snag. Park Tool notes that with some hub axle sizes an internally splined lockring may not be compatible, because the lockring tool cannot engage it. Its remedy is to switch to a lockring with external notches. If no tool will seat on your lockring, stop and take the wheel to a shop instead of improvising with pliers or a punch.
Adapting a 6-bolt rotor to a Center Lock hub
An adapter kit lets a 6-bolt rotor sit on a Center Lock hub. Park Tool notes that kits vary from design to design and shows two:
- Shimano example: the adapter mates with the hub, the rotor bolts thread through the rotor into the adapter, and the lockring goes on and is torqued last.
- DT Swiss example: the rotor engages six fittings on the adapter, then the lockring is threaded on and torqued.
Because the designs differ, follow the instructions and torque figures that came with your adapter. Park Tool says the reverse, a Center Lock rotor on a 6-bolt hub, is not possible. If your wheels have 6-bolt hubs, buy 6-bolt rotors.
Torque figures from the makers
Torque is tightening force, measured in newton-meters (N·m). The sources do not agree on one number for 6-bolt rotor bolts:
| Fastener | Figure | Source |
|---|---|---|
| 6-bolt rotor bolts | About 4 to 6 N·m, typical | Park Tool |
| SRAM 6-bolt rotor bolts | 6.2 N·m (55 in-lb) per bolt | SRAM manual |
| Shimano 6-bolt rotor bolts | 2 to 4 N·m (18 to 35 in-lb) | Shimano service instruction, January 2009 |
| SRAM Center Lock lockring | 40 N·m (354 in-lb) | SRAM manual |
| Shimano lockring (Center Lock) | 40 N·m (350 in-lb) | Shimano, 2009 instruction and June 2023 chart |
| Lockring from another maker | That maker’s figure | SRAM manual |
The spread is the point. Shimano’s low figure comes from an older document about its own bolt-and-plate design, so do not carry it over to a SRAM rotor. Use the figure in the instructions for your specific rotor, and use a torque wrench to hit it. For lockrings, SRAM and Shimano both give 40 N·m, and Park Tool’s example is also 40 N·m, but its instruction is to torque to the manufacturer’s specification.
Fitting rules that apply to both
- Direction. If the rotor has a direction arrow, fit it so the arrow points the way the wheel turns (Park Tool).
- Keep it clean. Shimano warns that oil or grease on the rotor and pads may stop the brakes working correctly. Park Tool says not to grease or oil rotor bolts, because braking heat can draw the oil out onto the rotor, and not to grease Center Lock parts either. Avoid touching the braking surface, then wipe both sides with isopropyl alcohol on a clean rag. Our bike washing guide covers degreaser near the brakes.
- Recheck the caliper. Spin the wheel after refitting. Rotors differ slightly, so the caliper may need realigning; the brake servicing guide explains caliper alignment.
- Allow for bed-in. SRAM says new pads and rotors need a wear-in process called bed-in, and Shimano says braking force increases gradually through the burn-in period. Do your pre-ride check, then test somewhere safe at low speed.
- Mind your hands. Shimano warns that a rotor is sharp enough to cause severe finger injury, and that calipers and rotors become hot in use. Let everything cool first.
When to stop and see a shop
- The rotor is bent. Park Tool says a bent rotor announces itself with a rhythmic rub or noise, and that it can sometimes be straightened but sometimes has to be replaced, so let a shop judge it. A rub right after fitting is not always a bent rotor: rotors differ slightly, so the caliper may only need realigning.
- The rotor is below its minimum thickness. Limits differ by maker. Park Tool says Shimano rotors are 1.8 mm when new and that Shimano wants them replaced before they wear below 1.5 mm. SRAM says to change a rotor once it is thinner than the minimum figure on the rotor, and gives 1.55 mm for its 1.85 mm rotors and 1.7 mm for its 2 mm rotors. Park Tool adds that brand-specific limits come from the manufacturer.
- Oil or grease reached the pads, or reached the rotor and braking does not return to normal after an isopropyl-alcohol wipe.
- The lockring tool will not seat or reach the lockring, or you cannot tighten the lockring to the maker’s figure.
- Braking feels weak, uneven or inconsistent after fitting and bed-in. Shimano’s rule is to make sure the front and rear brakes work correctly before you ride. Do not ride until they do.
Sources
- Park Tool: Disc Brake Rotor Removal & Installation
- SRAM: MTB disc brakes and shifters user manual
- Shimano: Technical Service Instructions SI-0095A-001, Installation of the rotor
- Shimano: DM-TORQUE-01 Dealer’s Manual, Torque Chart
Last reviewed: October 2026.