200mm Rotor vs. 203mm Rotor – What’s the Difference?
With the emergence of both 200mm and 203mm rotors it has created some confusion about the exact difference, and more specifically, the compatibility between the two. With SRAM making both 200mm and 203mm rotors and Shimano only making a 203mm rotor, it leads to a handful of questions. What is the spacing difference between the two? Are they interchangeable with each other? Do you need a different adapter or additional spacers? All of these questions will be answered below as we go over the exact differences between the two.
Sizing
With one rotor being 200mm and the other 203mm, the sizing difference between the two is 3mm of the radius. So it is only 1.5mm difference on either side, which is the distance that the caliper sits from the rotor. At the end of the day this sizing difference is very small, but it doesn't necessarily mean you can just swap your 200mm rotor for a 203mm and you will be good to go.
Are They Interchangeable?
It depends. Typically the best solution when going from a 200mm rotor to 203mm rotor, or vice-versa, is to use additional spacers, or take them out. It does depend on what brake adapter you are using though. More often than not, it just takes adding a 1.5mm spacer to accommodate the 203mm rotor on a 200mm adapter. Or, if you are going from a 203mm rotor to a 200mm, you can either take out spacers, or will need to get a 200mm brake adapter.
Compatibility Between SRAM and Shimano
SRAM and Shimano rotors can be interchanged and are compatible with each other, however, both manufacturers recommend running their rotors with each of their respective drivetrains for maximum performance. So a SRAM 203mm rotor can be swapped out with a Shimano 203mm rotor, and vice-versa. You can also go from a 200mm SRAM rotor to a 203mm Shimano rotor, assuming you have the correct brake adapter and spacers. It is not ideal or recommended, but it will work. For best performance, we would recommend running Shimano rotors with a Shimano setup and SRAM rotors with a SRAM setup.
Can You Use SRAM Rotors With Shimano Brakes?
Sram rotors can be used with Shimano's disc brakes, but the diameter of the rotor's should match the systems settings, as mentioned above. It is also important to make sure the rotors are compatible with the wheel's hub too. Check to see if the hub is bolt-on or centerlock. If you have bolt-on hubs, you will require a bolt-on rotor. If you have a centerlock hub, you will need a centerlock rotor. You also need to be cautious of brake pad overhang. Brake pad overhang occurs when a portion of the brake pad doesn't touch the rotor. Over time, the part of the brake pad that touches the rotor will wear and get slimmer, leaving the part that doesn't touch the rotor to not wear at all. Eventually the two areas that are unworn will touch each other and render the brakes useless, because the slimmer part that touches the rotor will have nothing to grab onto. Brake overhang can also sometimes be caused by an adapter thats too big for the current rotor.
Can You Use Shimano Rotors With SRAM Brakes?
Shimano rotors can be used with SRAM brakes. In some cases as mentioned above, you will need an adapter or an extra washer to increase clearance. Making sure the rotor diameter is compatible with your current disc brake setup is the first requirement to make sure they are compatible. To ensure the rotor you have is compatible will depend on the mounts, the calipers, and the presence or absence of adapters. You will also want to make sure the rotor and the brake pads are compatible. For example, some of Shimano's lower end rotors are softer and only meant to be used with organic/resin brake pads. So you would not want to use metal brake pads with that rotor. Double check to make sure the rotor you are using is compatible with the brake pads you have. As mentioned above, you will also want to make sure that the rotor and hub are compatible, being either bolt-on or centerlock.
If you are looking for either 200mm or 203mm rotors, we carry both. Click here to shop our full selection of rotors. Remember that we also offer free shipping on all orders over $149CAD in North America. Spend less and ride the best with TBS Bike Parts!