Condensed Answer: Standard road levers are designed for short pull brakes and do not operate properly with V-brakes. To combine the two, you will have to buy special road levers engineered specifically for V-brakes or install an adapter compensating for the different pull ratios.
Short and Long Pull Brakes
Cable-triggered brakes divide into short and long pulls depending on the cable’s travel.
The reason for the separation lies in the different mechanical advantage that the models offer.
Mechanical advantage a.k.a. leverage represents the amount of force amplification that a tool provides.
When it comes to cable brakes, the term mechanical advantage describes how hard the arms of the brakes grab the rim once the lever is squeezed.
Out of all rim brakes, V-brakes offer the greatest mechanical leverage because the cable is pulling from the most advantageous angle.
The greater mechanical advantage of V-brakes results in a longer travel of the brake lever.
This may seem a little confusing because the brain naturally associates higher mechanical advantage with less effort needed to produce results and subsequently a shorter travel of the used lever.
The effort part is true but the one about the travel isn’t.
The mechanical advantage of a tool can be measured by dividing the input displacement by the output displacement.
The formula looks as follows:
The greater the input displacement in relation to the output distance, the larger the mechanical advantage.
Let’s observe the operation of a simple lever.
In the image above, the B side of the lever is longer and subsequently has a greater mechanical advantage/leverage.
However, the longer arm also has a longer travel than the shorter one.
In the world of V-brakes, this means that the levers move more per 1mm of brake arm movement in comparison to brakes with a smaller mechanical advantage.
This creates a possibility for the lever to “bottom out” (touch the handlebars) before the brake arms have moved sufficiently to grab the rim to stop the wheel.
To avoid this outcome, V-brake levers are designed to pull more cable.
Conversely, other rim brakes (calipers, cantilevers, and mini V-brakes) offer a lower mechanical advantage.
This means that the input displacement is smaller and subsequently the levers don’t have to pull as much cable to trigger the brake.
If you combine short-pull brakes with long-pull levers, the brakes would lock the rim before the levers have reached the end of their travel. This would result in poor modulation (control over the braking force).
Summary of Part 1
1. V-brakes have a greater mechanical advantage than all other rim brakes.
2. The greater mechanical advantage results in a longer travel of the brake lever. To compensate, V-brake levers pull more cable.
3. If V-brakes are combined with a short-pull lever (e.g., road levers), the levers will be bottoming against the hoods before the brake arms have locked the rim.
4. If short-pull brakes are coupled with long-pull levers, the brake arms will lock the wheel too fast upon squeezing the lever.
How To Combine V-Brakes With Road Levers
Option 1: Switch to V-brake Road Levers
One of the possibilities is to get a set of road levers designed to work with V-brakes from the get-go.
The table below contains a list of models plus their weight:
|Tektro RL520 V
|Cane Creek V
|Dia Compe 287V Aero
The advantages of this method are:
The levers work with V-brakes right away. There’s no need to play with various adapters. As a result, the process is simple, and the bike looks streamlined.
The cons are:
V-brake road levers do not offer a dual control function. As a consequence, you won’t be able to brake and shift without changing your hand position. You will also have to install a shifting system that works independently of the brake levers.
The three most common options are:
a. Downtube shifters
b. Bar-end shifters
c. Stem shifters
Option 2: Adapters
You can also use a cable adapter that increases the amount of cable pulled by the lever. The increased cable pull allows the combination of road levers (short pull) with V-brakes (long pull).
One of the most popular models is called Travel Agent and is made by Problem Solvers. It replaces the V-brake’s noodle and doubles the cable pull via a system of small pulleys.
The main advantage of this solution is that you can keep your existing road levers.
Also, this is the only way to combine STI type of levers with V-brakes.
The downfall of adapters is that they don’t look clean and can be a bit difficult to set up.
Option 1: Switch to Mini V-brakes
Mini V-brakes are V-brakes with shorter arms offering similar braking power.
The shorter arms reduce the mechanical advantage and make mini V-brakes compatible with short pull levers such as those found on road bikes.
Nonetheless, mini V-brakes have some notable downsides, namely:
- Poor tire and mud clearance
- Complicated fender installation
- Very low tolerance of non-true rims
Option 2: Switch to Cantilever Brakes
Cantilever brakes are also short pull and are therefore compatible with road levers.
Their compatibility with road levers and great tire and mud clearance are the reasons why we find them on cyclocross bikes.
Cantilever brakes are a bit more difficult to tune but once adjusted properly they offer adequate braking power.
FAQ: Why Do Road Bikes Use Caliper Brakes Instead of V-brakes?
Road bikes favor simple, lightweight aero design. Caliper brakes fit the bill because they require a hole and a bolt to mount them. Thus, they save weight and keep the design slick in comparison to V-brakes which demand two separate bosses.
The absence of separate brake bosses in the case of caliper brakes simplifies fork and frame production.
Also, the mounting system of caliper brakes prevents the fork and frame from flexing when braking.
V-brakes, on the other hand, “encourage” flex which is the reason for the existence of V-brake reinforcers/boosters.
Caliper brakes have been the norm for many decades. Switching to V-brakes would go against a tradition. And since caliper brakes offer decent braking power, road bike users have been reluctant to start a rim brake revolution.
Summary: What You Need To Know
Standard road levers are short pull and are therefore compatible with caliper brakes, cantilevers and mini V-brakes.
There are two ways to combine road levers with V-brakes:
A. Purchase road levers designed specifically for V-brakes
This is the cleanest approach but requires you to give up your dual control levers (if you have them) and to install a separate shifting system (e.g., bar-end shifters.)
B. Purchase V-brake аdapters that increase the pull of road levers
This approach disrupts the lines of your bike somewhat but allows you to use the existing levers.