The Compatibility Of Rim Brakes and Disc Wheels Under a Microscope

A rim brake can operate with a disc brake wheel only when the rim has a stopping surface designed for the shoes of a rim brake. Otherwise, the rim brake won’t function efficiently.

Rim Brakes Need a Brake Track

Wheels designed for rim brakes have a rim with a brake track. The brake track is wide and vertical so that the brake shoe of a rim brake can grab it effectively.

Also, the track is reinforced (thicker) so that it doesn’t wear prematurely.

Wheels designed specifically for disc brakes have no need for a brake track. This allows the producer to make the rim lighter and give it a more aerodynamic shape.

As result, a rim brake shoe cannot effectively grab a disc-only rim. To increase the contact area, one will have to run the rim brake dangerously close to the tire. This may result in rubbing and a tire blowout.

The only way to use a rim brake with a disc wheel is to buy or build a wheel that can take both – disc and rim brakes.

Such a wheel covers two requirements:

  • A Disc Brake Hub

The wheel needs to have a disc brake hub to which one can attach a brake rotor. Standard rim brake wheels do not have this option as rim brakes don’t use rotors.

  • A Brake Track

As explained above, the rim needs to have a brake track, or else it cannot be safely used with rim brakes.

Some people may think that a disc wheel needs a disc-specific rim, but that isn’t the case. A rim is a rim. Thus, a rim designed for rim brakes can be used for a disc wheel.

That said, it’s recommended to stay away from rims that use fewer spokes. When braking via disc brakes, the spokes have to deal with a lot of stress. If the bike wheel has a minimal number of spokes, it may fail to withstand the extra force.

Ultimately, it’s best to stick with 32 or 36 spokes per wheel.

The downside of using a combo wheel (designed for both braking systems) is a potential weight penalty due to the extra material needed for the brake track and the disc-ready hub.

In practice, however, the actual weight of the rim depends more on the model than the brake it’s designed for.

The table below compares the weight of 28″ rims depending on brake type. As you can see, the average weight of the rims is pretty similar.

In fact, the disc brake rims in the table are 37.28 grams heavier on average.

Rim Brake RimsWeightDisc Brake RimsWeight
Mavic Open Pro C 28″435gDT Swiss R 470450g
DT Swiss R 460460gDT Swiss G 540565g
Mavic A 119 28″540gH+SON Formation Face 28″615g
DT Swiss RR 511530gH+SON The Hydra 28″ 455g
Mavic CXP 28″510gWhite Industries G25A490g
DT Swiss X 412440gMavic E-XM 430 Disc590g
Ryde Trace R 20 OS474gDT Swiss RR 481 485g
Rim Weight Comparison

The next table compares the weight of front hubs. The first column is made of hubs designed for a rim brake whereas the second consists of disc-brake ready hubs:

Rim Brake HubWeightFront Brake HubWeight
White Industries T1192gShimano XT HB-M756239g
DT Swiss 350110gWhite Industries XMR 6-Bolt Disc175g
tune Mig Front Hub73gHope Pro 4 Disc 6-Bolt Front Hub173g
White Industries MI5 122.6gDT Swiss 240 Classic190g
Novatec A291 SB-SL 60gDT Swiss 240 Straight Pull 111g
Mavic Road UB Front Hub103gSRAM Predictive Steering Front Hub165g
Hub Weight Comparison

Conclusion: The “rim brake” front hubs are 53% lighter than the disc-brake-ready ones. Part of the reason for that is that many rim brake hubs are designed for road bikes and are thus made lighter.

Conversely, disc brake hubs are common on MTBs and are subsequently more robust to cope with the terrain.

By building a rim that’s rim and disc-brake ready, one can expect a bit extra weight (approx. 100 grams) due to the disc hub.

Summary: What You Need To Know

  • A rim brake requires the rim to have a brake track. If the rim doesn’t have one, the braking won’t be effective.
  • Most disc-ready rims are not built for rim brakes and thus do not have a brake track. This allows manufacturers to make the rim more aerodynamic.
  • It’s possible to build a wheel that can operate with both – a rim and a disc brake. To do that, you will need a rim with a brake track and a hub with mounting points for a disc rotor.

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