Theoretically, it’s possible to equip a BMX bike with disc brakes if you’re willing to invest a lot of time, money, and effort. The process isn’t straightforward because most BMX bikes aren’t built with disc brakes in mind.
Requirements To Install Disc Brakes On a BMX Bike
To install a disc brake, the following criteria have to be met:
1. Disc Ready Hubs
Disc brakes operate with rotors that attach to the hub of the wheel via bolts. If the hubs don’t have mounting points for a rotor, you will have to buy new hubs and re-lace the wheels.
Note: Since BMX bike haves narrower hubs, you won’t be able to use one from a mountain bike.
The O.L.D. (Over Locknut Dimension) of a rear BMX hub is 110mm whereas that of a modern MTB is 135mm.
The term Over Locknut Dimension (O.L.D.) refers to the usable part of the hub or the distance between the outer sides of the two locknuts.
The narrower O.L.D. of BMX bikes greatly limits the number of hubs that you can use for a disc brake conversion.
2. Caliper Mounts
Apart from some race models which have mounts for a rear caliper, BMX bikes come without mounts for disc brake calipers.
If you want to run a front disc brake, you would have to search for an alternative solution.
One option would be to use a 20″ mod trials fork. You could also get in touch with an experienced frame builder and tell him to install caliper mounts on your pre-existing fork and frame.
Note: This welding method will void all warranties because you will be modifying the components in a manner non-approved by the manufacturer.
Disc Brake Kits
If the bike doesn’t have mounts and welding isn’t an option, one could use BMX disc brake kits which come with disc brake adapters connecting directly to the bike’s rear hub and dropouts.
RideMiSC and Eleven are two companies producing disc brake kits for BMX race bikes.
Freestyle BMX Bikes Don’t Like Disc Brakes
You would never see a serious freestyle rider with disc brakes on their bike because:
- The rotors can easily bend during tricks.
- The rotors can cut the rider during training.
- Many freestylers ride brakeless for simplicity and facilitation of certain tricks such as bar spins.
- Disc brakes add weight and extra cables to the bike.
Conversely, BMX riders who race and/or jump a lot may find disc brake beneficial. In all other cases, however, a rim brake is a better choice.
List Of Disc-Brake-Ready BMX Race Bikes
Below you will find a list of BMX race bikes and frames that support disc brakes:
1. Zenith Disc XX (full bike)
2. YESS MX-Y 20″ (frame only)
3. DK ZENITH DISK 24″(full bike)
4. GT Speed Series MK7 (full bike)
5. YESS MX-Y 24″ DIS (frame only)
FAQ: Do BMX frames need extra reinforcement to use disc brakes?
An extra bracket connecting the seatstay and the chainstay on the disc side wouldn’t hurt, but in most cases, BMX frames are stiff enough to handle the pressure even without additional reinforcement. Mountain bikes don’t have such brackets and have been operating just fine for years.
And when you think about it, some BMX frames are notably stronger than standard MTB models.
If that’s the case, why would BMX frames need extra reinforcement when they’re built super strong and stiff, to begin with?
FAQ: How Can I Maximize Stopping Power Without Disc Brakes?
You can take the following steps to improve the stopping power of your BMX without resorting to disc brakes:
1. Use a rear and front rim brake.
If you have been running a single rear brake, adding a front one will massively improve your stopping power.
2. Replace the cables, housing and the brake pads.
3. Switch to higher-end rim brakes, brake levers and rims.
Summary: What You Need To Know
All Options Listed
Since the information above could be a bit overwhelming, I’ve compiled a list of all available options for installing disc brakes on a BMX bike:
1. Do it yourself
If you want to install disc brakes on a BMX by yourself, you will have to do the following:
- Re-lace the wheels with disc-ready hubs. Install disc rotors on the wheels.
- Weld mounts to the fork and frame. This is possible only if the frame is made of steel. Aluminum doesn’t like after-market welding.
- Install the brakes
- Tidy the cable routing
Pros of This Method
- Can be done to almost any frame
- Clean look
Cons of This Method
- The hubs and the re-lacing of the wheel won’t be cheap.
- You will need a professional welder if you aren’t one. This will raise the cost even higher.
- The warranty of the frame and fork will be instantly lost.
2. Disc Brake Kits
The other option is to use a pre-made disc brake kit that mounts to the rear axle and dropouts.
The Pros of This Method
- Does not require welding
The Cons of This Method
- A disc brake can be installed only on the rear.
- The kit could be expensive, especially if you have to order it from overseas (extra fees may apply).
3. Buy a Disc Ready Frame
If you’re into BMX racing, you can buy a frame or an entire disc-ready bike.
The Pros of This Method
- You don’t have to re-purpose the bike since it’s already designed for a disc brake.
The Cons of This Method
- Disc-ready frames and bikes are expensive.
- No disc brake at the front
4. Install a Trials Fork
Another option would be to get a 20″ trials fork with disc mounts. The fork has to match the length of your pre-existing BMX one.
The Pros of This Method
- Welding is not required
The Cons of This Method
- You will be able to install only one disc brake.
- Many trials forks are made of aluminum to save weight. Aluminum is not the preferred material for BMX tricks because it’s soft and can’t handle impact like steel.
- The fit may be off.
- You will lose the classic BMX look.
Alternative Option: Switch to a 24″ or 26″ Inch MTB
If you ride big jumps rather than focusing on super technical tricks, you can consider switching to a 24″ or 26″ dirt jumper. Dirt jumpers come with a rear disc brake and a front suspension fork that can accommodate another one if you so desire.
24″ models will feel as close as possible to a BMX whereas the larger 26″ ones will be a bit faster but less technical due to the extra size.
FAQ: Is there a cheap solution?
No. Installing a disc brake on a BMX bike is technically a “mod” rather than a mass production event. For that reason, you will have to pay a premium price.
The cheapest solution is to simply stick with high-quality V-brakes. Truth be told, the stopping power of a top-of-the-line V-brake is more than enough for most people.
Is it worth it? What are the pros and cons?
Disc brakes are superior to rim brakes in all regards other than weight and discreteness (disc brakes are more in your face).
However, given the amount of work and the money required to make the project a success, it’s hard to say with great certainty that the “adventure” will be worth it.
If you don’t have a big budget and lots of patience, it will be wiser to abort the mission and stick to the classics.
