Mountain bikers have known for a long time that disc brakes have superior stopping power under adverse conditions over rim brakes. Hydraulic disc brakes will magnify the stopping force of your hands, while disc rotors are better at stopping even in mud, wet, and dirt. The technology is trickling over into other riding disciplines, such as gravel and road.
But what if you already have a bike you love that’s fitted with rim brakes or V-brakes? Can you retrofit disc brakes on a non-disc bike frame?
Theoretically, you should be able to retrofit your bike with disc brakes. It would definitely be one of the bike upgrades you would notice and appreciate on your rides. However, there are many reasons you probably don’t want to. In this article, we’ll take a look at what it would take to retrofit your rim brake bike with disc brakes and why it isn’t actually worth it.
Reasons to Upgrade Your Bike to Disc Brakes
Rim brakes were the standard on bikes of all types for many years. When you squeeze the brake levers, the cable running to the brakes closes the brake pads around the rim of the wheel. The friction on the wheel from the brake pads slows the spinning of the wheel, thus slowing the bike.
The problem with rim brakes is that they significantly limit the tire clearance you have on your bike. You can only fit a tire as wide as will fit inside the brakes. Rim brakes are more subject to not working as well in bad weather, and they wear down more quickly when it’s wet. Some say that the tire’s rim can heat up too much on steep descents and cause blowouts. So these are all excellent reasons to switch to disc brakes.
Disc brakes have a rotor that is attached to the wheel at the hub. The brake pads squeeze the rotor rather than the rim of the wheel. This gives you plenty more clearance for wider tires (as wide as your frames will allow), and the brakes handle better in bad weather. They also give you more stopping power with less hand strength.
Keep in mind that while hydraulic disc brakes magnify your stopping power, mechanical disc brakes do not.
With the popularity of gravel bikes, which need wider tires, disc brakes are the standard on all models. They have become the default on road bikes too, as buyers have come to expect them.
Retrofitting Your Bike with Disc Brakes
So while you can retrofit your bike with disc brakes, it isn’t a simple process because the bikes and brakes are so different. In order to convert your rim brake or V-brake bike to disc brakes, you’ll need to make some big changes and investments to your bike.
First, the bike frame is different. Your rim brake frame holds the brakes to the bike at the apex of the fork, and the brakes are fitted around the rim.
On a disc brake bike, the rotor is attached at the hub of the wheel, while the brakes are connected to the side of the fork. The frame of a disc brake bike, especially if it’s carbon, is layered and shaped differently because disc brakes apply stress to different parts of the bike frame. A rim brake frame simply isn’t created to withstand the different type of pressure from disc brakes, and this may cause premature frame damage and even injury.
If you convert from rim brakes to hydraulic disc brakes, you’ll need new brake levers, cables, and hydraulic brake fluid for bikes.
You’ll have to replace the front fork of your bike with a fork that can accommodate the mounts needed to hold the brakes in place. This can be expensive, especially if you want a carbon fork to absorb some of the road chatter.
Wheels and Hubs
You’ll also have to get new wheels with disc brake hubs. Rim brake wheels are designed to withstand the pressure of the brake on the rims, but disc brakes need to attach at the hub. So the same wheels won’t work on a disc brake bike as you would use on a rim brake bike. Wheel sets are one of the most expensive parts of your bike.
Rear Fork Conversion Kit
Since you can’t just replace the rear fork of your bike, you’ll need a conversion kit that will attach rear disc brakes to the rear fork. And while some people do find success using these types of kits, they can be finicky, heavy, and hard to attach.
While many home bike mechanics enjoy the project if they have the right bike shop tools on hand, it is not uncommon to spend four figures on the upgrade if you bring it in to a bike shop. For that price, you can purchase a pretty awesome brand-new bike already fitted with disc brakes.
Retrofitting your bike with disc brakes is expensive, time-consuming, and probably not as safe as just investing in a new frame. So if you’re currently riding with rim brakes, relax and enjoy the ride! Rather than spending all the time and money to upgrade your bike, save your pennies to invest in a bike already outfitted with disc brakes.
I recommend that you simply purchase a new or high-quality used bike, rather than taking on the very expensive task of retrofitting a bike.
Amanda Whittington is an accomplished adventure cyclist, having done some of America’s iconic bike races, century rides, gravel grinders, cross-country races, and is currently training for track racing. A ride leader and organizer, Amanda is passionate about cycling and teaching others, and works with beginner riders, teaching them group riding and bike safety as well as basic bike know-how.