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Questions and answers about sports

How to chose the correct hydraulic disc brake rotor size for touring bike?

5 min read

Asked by: Maurice Olsen

How do I know what size brake rotors I need?

Call your local OEM dealer and ask for the original rotor sizes or OEM rotor/pads part numbers based on your vehicle’s VIN number (VIN# is referenced in your ownership papers). The dealership may not tell you the rotor size, but they will give you the genuine part numbers for your vehicle.

How do I know my bike rotor size?


  1. ID = Inside Diameter: Measure from inside edge to inside edge.
  2. OD = Outside Diameter: Measure from outside edge to outside edge.
  3. Measurement from inside edge of mounting hole to inside edge of bolt hole.
  4. Bolt hole diameter: measure from inside edge of bolt hole to opposite inside edge.

How do I choose brake disc size?

The best way to ensure you get the correct brake discs is to check the diameter of the brake discs already fitted. The diameter and thickness of the disc is illustrated below. To measure the diameter you may not have to remove the wheel, however it would make the measuring process easier.

Does size of brake rotor matter?

Size And Weight

A larger brake rotor has more surface area for the heat to spread across, making it more thermally efficient. This means that your brakes will perform better. The downside to the larger rotor is increased weight, caliper size, and the need for larger wheels.

How do I choose rotors?

How to Select Brake Rotors

  1. Smooth rotors offer the quietest operation, lowest dust and longest pad life. …
  2. Drilled rotors offer slightly more bite and friction than slotted rotors. …
  3. Slotted & Drilled rotors offer a compromise, midway between the benefits of slotted rotors and drilled rotors.

Are front and rear rotors the same size?

The front and rear brake rotors are not the same. The front rotors are bigger than the rear rotors. So, technically, they do not perform the same job. The front rotors handle most of the braking power, and that’s why the front pads wear faster than the rear pads.

Can I put a bigger rotor on my bike?

Yes, but there isn’t much in it at all. SRAM and Shimano both claim a weight gain of just 20g per rotor when switching from a 140 to a 160mm size, and if your frame is designed to take 160mm rotors natively, you can throw away the adaptor that many setups use.

Do bigger rotors stop better?

Having bigger rotors means better heat transfer and better performance stopping.

Why are front rotors bigger than rear?

The front rotor is bigger because you CAN brake more with the front before losing traction. The rear rotor is smaller because a whole lot of extra braking force is just going to make the wheel lock up anyway, so a bigger rotor would just be a waste.

How many mm should brake discs be?

Two to three millimetres of wear are generally acceptable. Natural brake disc wear is relatively easy to detect. When a disc is worn, a burr can be felt at the rim, as the disc only becomes worn where the brake pad is applied. The more pronounced the burr, the worse the disc wear is.

Can I use any rotor with disc brakes?

You can use any rotor you like with any brake, within reason. Some rotors have narrower brake tracks than others, i.e. Shimano, but generally, it’s just a metal disk.

How do you measure a rotor height?

Hold a gauge across the top of the brake rotor hat. Then using a detailed measuring tool, measure the distance from the face of the brake rotor to the hat height gauge.

Are drilled rotors better than solid?

Some drivers feel that drilled rotors perform better in wet conditions than any other rotor design. Drilled rotors are lighter than traditional smooth rotors. Because of this, drilled rotors have lower rotational inertia. That means your vehicle can accelerate and stop faster with drilled rotors.

Do all brake rotors fit?

Brake rotors and pads are not universal to all cars but can be interchangeable between certain vehicles. The sizing of the pads and rotors, hub bore/pattern, and wheel size are just a few factors that have to be checked before even attempting a swap.

Can I put bigger rotors on my car?

Just installing larger rotors won’t do anything for performance and you may have clearance issues with the smaller caliper brackets, not to mention out of spec rotor wear that might cause braking issues. If you want to change rotor size, you should be installing calipers to match.

Are all brake rotors the same?

When it comes time to replace your rotors, keep in mind that not all rotors are made the same. In fact, there are four different types to choose from, so before replacing your vehicle’s rotors, make sure you’re choosing the right one for your needs.

How do you measure brake pads without removing wheels?

Quote from video: Until you have a clear picture of your brake caliper caliper bracket and the actual brake pad. And as you say the brake pad outer brake pad is sunken down pretty good on this particular vehicle.

How do you measure rotor thickness?

To measure your rotor’s minimum operational thickness, place a micrometer at the thinnest point on the rotor’s surface where it meets the brake pads. If your rotor has worn past this thickness or needs to be cut, you need new rotors.

How thick should my rotors be?

Quote from video: You can find the minimum operational thickness engraved on the side of the rotor. Within the veins of the rotor. Or on the head of the rotor.

What happens if rotors are too thin?

When a rotor is too thin, it overheats and warps, leading to an annoying vibration or pedal pulsation. When rotors were thicker, they could take the wear from the brake pads, be machined and still have enough metal left to dissipate the heat.