Bike Theory: From Calipers To Vs

from Rookie’s keyboard,

Hello, friends

Due to popular demand, today I will discuss the possibility of mounting V-brakes on a frame and fork originally designed for calipers. I don’t know why, but I’ve had 3 requests to write an article on that topic in the last month. So, who am I to argue with my readers’ demands?

Let’s go straight into the technical aspects.

Requirements 

V-brake Mounts

The brake arms of V-brakes are secured to the frame/fork via two bolts threaded into the so-called brake bosses/mounts.

In the case of steel frames, the mounts are brazed to the frame or fork. Brazing is a metal-joining process during which two pieces of metal are attached by melting a third metal (usually brass or silver) over the connection area.

The advantage of brazing is that it doesn’t overheat the base material (only the filler rod) and therefore doesn’t alter the integrity of the tubing.

If the frame is made of aluminum alloy, brazing cannot be used because aluminum has a low melting point and will be damaged during the process. Hence the mounts are TIG-welded.

Meanwhile, caliper brakes are secured to the frame or fork via a single bolt passing through the fork’s crown or the seat stay bridge. For that reason, a large percentage of bikes originally designed for caliper brakes do not have V-brake mounts.

If that’s you, the options are:

Buy a New Fork

The simplest solution is to get a new fork with V-brake mounts. That option isn’t a bad choice because most stopping power comes from the front brake.

When you brake, there’s a weight shift to the front. And the rear tire is partially unweighted. The reduced traction increases the chance of sliding when the rear wheel locks.

Conversely, the front wheel has extra traction during braking and much lower chances of sliding. Hence why people consider front brakes essential.

The new fork will have to meet the following requirements:

• Compatible with the bike’s head tube

The new fork should be the same type as the old one and have the same thickness. Otherwise, it will be impossible to safely install it.

From the perspective of the retention mechanism, there are two types of forks – threaded and threadless.

Threaded forks are attached to the head tube via the threaded cup of the headset. Threadless forks do not have a threaded steerer and are fastened by the bike’s stem instead.

Тhreaded forks are considered antiquated and come with a quill stem. 

It’s technically possible to switch between threaded and threadless forks, but the swap requires a great number of properties to align correctly. It’s best to stick to the original type if possible.

Steerer Thickness

The steerer is the fork’s tube that passes through the head tube. The steerer of the new fork should match the thickness and shape of the original. If the new steerer is too thick, it won’t pass through the head tube.

Steerer Length

The fork’s length is crucial. A short fork will lower the height of the handlebars or even make the installation impossible.

Meanwhile, a long fork will elevate the handlebars and thus change the bike fit. Ideally, you will find a fork with a steerer as long as the old one.

Axle To Crown Length(ATC)

The Axle to Crown (ATC) is the distance between the fork’s dropouts and its crown. The new and the old fork should have matching (or close to it) ATCs.

If the ATC of the new fork is shorter, the wheel may fail to fit. If the ATC is a lot longer, the head tube angle of the bike will get slacker and the handling will change.

Get a New Frame

A more radical approach would be to replace the entire frame with a V-brake-ready one. This procedure is even more complicated than replacing the fork as you will have to re-install all the components.

The new frame should be:

• As big as the old one
• Compatible with the fork
• Equipped with V-brake mounts

Braze or Weld V-brake Mounts 

An elegant solution is to weld or braze a set of V-brake mounts on the frame or fork. This method requires several skills and equipment that most of us simply don’t have. 

The procedure will be more expensive when working with aluminum because the material requires more complex welding equipment. 

Also, aluminum loses strength from the heat generated during welding and requires additional heat treatment. 

The final bill will probably exceed the price of a new fork or even a bike. 

Clamp-On V-Mounts

V-brake Clamp Adapters

Another solution is to install clamp-on V-brake mounts. The obvious pro of this method is that you don’t need welding skills.

The downside is the price. Those things aren’t cheap.

Why Bother?

The main benefits of the switch from calipers to Vs would be:

Tire Clearance

Calipers limit the tire size that users can install whereas V-brakes are an MTB invention and compatible with wide, balloon tires.

The extra clearance makes it possible to run full fenders too.

Extra Braking Force

V-brakes have more leverage than calipers thanks to their longer arms and more advantageous pulling angles. Quality V-brakes are comparable to a set of disc brakes when operating in dry conditions.

The dissimilar leverage requires levers pulling a dissimilar amount of cable.

Caliper brakes have a smaller mechanical advantage and operate with brake levers pulling less cable. Otherwise, the wheel will lock before the brake lever has completed its full travel.

Meanwhile, the extra leverage of V-brakes turns them into “long pull brakes”. If they’re combined with short pull levers, the lever will reach its full travel before the brakes have maximally grabbed the wheel.

• Cheaper

Calipers are a road bike component and tend to be expensive. Meanwhile, a decent set of V-brakes can be had for a reasonable sum.

• Suspension-friendly

A caliper brake is mounted to the fork crown whereas a V-brake goes on the fork’s legs. 

Consequently, it’s possible to use a V-brake with a suspension fork.

A caliper brake cannot be combined with a suspension fork because it will move up and down along with the crown, and the brake won’t be in line with the rim at all times.

Should you do it?

Honestly, don’t bother. Stick with whatever your bike is designed for. Calipers are plenty strong for road bikes.

Don’t waste your time making silly changes, friend. Go ride. Enjoy life.

Until next time,

– Rookie