What Are Mini V-Brakes?
Mini V-brakes are a slightly smaller version of the popular Shimano direct-pull cantilever brakes known as V-brakes.
Unlike regular cantilever brakes which operate with a transverse cable, V-brakes and mini V-brakes pull the brake arms directly, hence the term direct pull.
The only difference between mini V-brakes and regular V-brakes is the length of the brake arms.
Mini V-brake arms have shorter brake arms, usually, around 80-85mm, whereas the brake arms of standard V-brakes are 100mm.
The actual length of the brake arms depends on the manufacturer and the particular model.
What is the Purpose of Mini V-Brakes?
Due to the shorter brake arms, mini V-brakes have a lower mechanical advantage (leverage) than regular V-brakes. This is a purposefully sought effect.
The term mechanical advantage describes the ratio between the output and input force in a system.
The mechanical advantage of a tool is high when the output force is greater than the input force.
However, when the mechanical advantage is displayed as a form of displacement, the formula is reversed.
In that case, a high mechanical advantage requires the input displacement to be greater than the output displacement.
At first, this may sound a little confusing, but the confusion should clear upon observing the operation of a simple lever.
If we use the long arm of a lever to insert force, we benefit from a greater mechanical advantage multiplying our effort.
The long arm (the one with more mechanical advantage), has a longer travel than the shorter one. (image below)
Or in other words, the input is longer than the output.
In the world of V-brakes and mini V-brakes, those principles translate to the following conclusions:
1. V-Brakes = Highest Mechanical Advantage = Long Pull Levers
V-brakes have a higher mechanical than both cantilever and mini V-brakes.
Therefore, the input displacement of V-brakes, or in other words the movement of the brake lever, is greater/longer than the output displacement or the travel of the brake arm.
This creates a possibility for the lever to “bottom out” (touch the handlebars) before the brake arms have moved sufficiently to grab the rim and stop the wheel.
To avoid this issue, V-brake levers are designed to pull more cable than all other levers.
In consequence, V-brakes are incompatible with cantilever, mini-V brake, and traditional drop bar levers.
2. Mini V-brakes = Lower Mechanical Advantage = Short Pull
Mini V-brakes have shorter brake arms and a lower mechanical advantage than V-brakes.
As a result, the input displacement (brake lever travel) causes a greater output displacement (brake arm travel).
In consequence, mini V-brake levers are designed not to pull as much cable as regular V-brakes.
This characteristic makes mini V-brakes compatible with short-pull brake levers that can be mounted on a drop bar.
If mini V-brakes are combined with brake levers made for standard V-brakes, the greater amount of cable pull will result in poor modulation and unsatisfactory performance.
Conclusion: Mini V-brakes make it possible to combine direct-pull cantilevers with short-pull brake levers.
The Clearance of Mini V-Brakes Is Dependent on Their Length
80mm V-brake models have the lowest leverage whereas the 90mm versions have the highest.
Since the length of the brake arms changes the mechanical advantage, it has an effect on the brakes’ clearance too.
Here’s how that works:
Shorter arms = Lower Mechanical Advantage = Larger Output Displacement (Movement of the Arms)
Longer arms = Higher Mechanical Advantage = Smaller Output Displacement (Movement of the Arms)
Longer arms require the pad to be closer to the rim because otherwise, the lever may bottom out before full engagement of the brakes.
Conversely, shorter arms allow you to run the pads further away from the rim because they have a lower mechanical advantage and the output displacement is larger.
(In this case, the brake lever has the capacity to move the pad over a greater distance.)
In short, more mechanical advantage equals less brake pad clearance.
That said, longer arms result in greater vertical clearance because the noodle ends up sitting a bit higher.
In general, however, most people try to find mini V-brakes with less mechanical advantage and thus greater pad clearance to reduce the need for frequent truing of the wheel.
FAQ: Are there mini V-brakes designed specifically for cyclo-cross?
TRP CX 8.4 are made with cyclocross racing in mind.
Advantages of Mini V-Brakes
Below you will find the advantages of mini V-brakes:
1. Compatibility with Drop Bar Brake-shifters (e.g., STI)
One of mini V-brakes’ main advantages is their compatibility with drop bar brake-shifters such as STI.
This allows the installation of mini V-brakes on bicycles with drop bar levers and mounting points for V-brakes.
The usual candidates are cyclo-cross, touring, and commuting bicycles.
2. Quicker Adjustment
Just like regular V-brakes, mini Vs do not have a straddle cable to play with. This makes the adjustment of the brakes faster and simpler because the mechanical advantage is pre-set and unchangeable.
This point alone is a strong motivation for many people to replace their cantilever brakes with mini Vs.
3. Great Stopping Power
Many say that cantilever brakes can work just as well as V-brakes or mini Vs when adjusted properly.
True or not, this doesn’t change the fact that cantilever brakes will never offer more stopping power than V-brakes for one simple reason – V-brakes are cantilever brakes operating with the highest possible mechanical advantage.
When you take into account that V-brakes offer the maximum stopping power of cantilevers in combination with a simpler installation process, it becomes obvious why the market of cantilevers is so small.
Some mini V-brakes are very affordable and offer great stopping power for the price.
5. Less Hand Force Required To Stop
The greater mechanical advantage of mini V-brakes reduces the amount of finger pressure needed to squeeze the levers and initiate braking.
Disadvantages of Mini V-Brakes
Below you will find the disadvantages of mini V-brakes:
1. Poor Clearance
The shorter arms of mini V-brakes reduce the brakes’ clearance by bringing the noodle, the quick release, the boot, and the cable very close to the tire.
This creates the following problems:
Inability to Run MTB tires. Mini V-brakes are designed with cyclo-cross tires in mind and cannot accept large mountain bike or commuter tires;
Difficult to Fit fenders. Mini V-brakes could make the installation of fenders impossible due to the lack of space.
If you plan on using fenders, go to a local store and check if they can work with your mini V-brakes.
Difficult Installation and Removal of the Wheels. Sometimes mini V-brakes make the removal and installation of a wheel more difficult due to the lack of clearance.
In some extreme cases, it’s necessary to deflate the tire prior to removing the wheel.
In general, however, the process is as follows:
- Squeeze the brake arms.
- Remove the noodle (metal cable guide) by pulling it out of the cradle’s U-shaped stirrup
- Release the brake arms.
2. Low Tolerance of Non-True Rims
To prevent bottoming out of the brake lever, the pads of mini V-brakes often have to be super close to the rim.
Consequently, the pads begin rubbing against the rim as soon as the wheel gets out of true even a little bit. This scenario can be very annoying, especially for people who don’t have the skills and the equipment needed to straighten the wheel.
Advantages of Cantilever Brakes
The next segment focuses on the advantages of cantilever brakes:
1. Better Clearance
Cantilever brakes offer better tire clearance than both mini V-brakes and standard V-brakes and give you the opportunity to fit wider tires.
Cantilevers are also less prone to accumulating dirt which is why low profile cantis were the norm for cyclo-cross bikes before the disc brake revolution.
The extra clearance has two more bonuses:
- Easier installation/removal of the wheel;
- Space for fenders;
2. Higher Non-True Rim Tolerance
Cantilever brakes are more tolerant of rim imperfections because the pads do not have to be as close to the rim due to the lower mechanical advantage. Hence why cantilevers are less likely cause brake rubbing.
3. Extra Adjustments
Cantilever brakes allow you to play with the mechanical advantage of the brakes by adjusting the straddle wire/cable. Some mechanics and riders appreciate this option.
Disadvantages of Cantilever Brakes
The disadvantages of cantilever brakes are:
1. Fork Shuddering
Cantilevers are notorious for causing intolerable vibrations within the fork when stopping. The problem occurs when the cable hanger is above the headset.
The mechanism behind the shuddering is as follows:
1. During braking, the inertia is pushing the bike forward while the wheel is either locked (hard braking) or partially prevented from rolling forward (slower braking).
The wheel “bites” against the ground to a degree determined by the level friction. In return, the ground pushes the wheel backwards and the fork has no choice but to flex backward too.
2. When the fork flexes backward, it stretches the brake cable. The motion has the effect of squeezing the brake because the stretch of the cable pushes the pads into the rim even more.
The end result is more braking and consequently more backward flexion of the fork.
3. As the bike slows down, the kinetic energy diminishes and so does the backward force applied by the ground onto the wheel and the fork.
The reduced fork flexion releases some of the cable tension and lowers the clamping force of the pads. In consequence, the chattering effect decreases, and eventually, the fork calms down.
The springiness of the fork adds to the “tension release”. After bending, the fork begins fighting to assume its normal shape as soon as possible.
If the rider lowers the force applied on the lever, the shuddering will decrease. However, as soon as the brake is reapplied, the vicious cycle will begin once again.
The common way to resolve this issue is to mount a cable stopper on the fork (image below) and run the brake cable through it rather than the headset.
This method reduces the bow effect by bringing the two anchor points closer together.
Having said that, brake juddering may steel appear but to a small degree.
Mini V-brakes, on the other hand, do not have that problem by default.
2. Difficult to Adjust
Cantilever brakes, especially, the old versions, can be very frustrating for people who don’t have the necessary experience.
Individuals who love messing with their bikes may appreciate the extra adjustability, but the vast majority of the crowd rarely shares the same enthusiasm.
Cantilevers can theoretically offer braking power equal or close to that of V-brakes, but due to the greater number of variables, most people find it difficult to tap into that potential.
3. The Modern Models Are Expensive
Up-to-date cantilever brakes solve issues common for the older versions and perform very well. However, their price could be high for people on a budget.
FAQ: Is it possible to combine regular V-Brakes with brake-shifters?
There are two ways to combine regular V-brakes with road levers:
Option 1: V-brake Levers + External Shifters
Some companies produce drop bar brake levers adjusted for the long cable pull required by normal size V-brakes.
Unfortunately, those models come without a shifting option and require the use of external shifters such as bar-ends.
Option 2: Travel Agent Adapters + Brake-shifters
Travel Agents are special adaptors increasing the cable pull of a lever. By doing so, they allow riders to combine V-brakes with standard brake-shifters.
FAQ: Are Mini V-Brakes Heavier Than Cantilever Brakes?
To answer this question, I gathered some weight data shown in the table below:
|Mini V-Brakes||Weight (per unit)||Cantilevers||Weight (per unit)|
|Tektro RX6||144 grams||Tektro CR720||126 grams|
|Tektro RX1||150 grams||Tektro CR510||144 grams|
|Tektro 926 AL||160 grams||Avid Shorty Ultimate||129 grams|
|XLC BR-V04||150 grams||TRP RevoX Carbon||130 grams|
|Mini Moto||149 grams||Shimano BR-CX70||165 grams|
|TRP 8.4||170 grams||FSA SL-К CX||136 grams|
|Average:||153.8 grams||Average:||138.3 grams|
Conclusion: Cantilever brakes are 10% lighter on average than mini V-brakes. However, it’s unlikely for a non-pro cyclist to ever notice such a small difference.
The tables below contain the advantages and disadvantages of both brake systems:
|Decent braking power||Poor Tire Clearance|
|Easy installation and adjustment||Poor “Mud clearance”|
|Affordable models||Difficult to Install Fenders|
|Higher mechanical advantage||No Tolerance to Non-True Rims|
|Comptability with brake-shifters|
|Good Tire Clearance||Tricky adjustment|
|Good “Mud Clearance”||Lack of braking power unless perfectly adjusted|
|Space For Fenders||Squeaky|
|Compatibility with Brake Shifters||Possibly Fork Shuddering|