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MTB Tech: Gearbox vs Traditional Drivetrain Systems

Click here to read more about the Deviate Guide, a full carbon gearbox bike that is featured in this article.

 

Not many cyclists are familiar with the gearbox system as it has only been popular in the recent years. There are many advantages of a gearbox system as compared to a traditional drivetrain. Click here for a more comprehensive look into the internal mechanisms of the pinion gearbox. 

So, what’s so good about a gearbox system on a mountain bike? 

 

#1. Low maintenance

You will only need to replace the 60cc capacity oil in the gearbox every once a year. 

The fully enclosed nature of the gearbox protects the precision drive train components from the mud, dust, water, and rocks from the trails. Currently, the external derailleur system is entirely open to these elements. Sticks often get stuck in shifting systems and violently rip derailleurs off frames. Mud and rocks easily get stuck in the small pulley wheels and springs of a derailleur and cause the system to jam.

 

 

#2. Higher clearance from the ground

The external derailleur system on a traditional drivetrain is vulnerable to failures as the components such as the hanger and rear derailleurs are in close proximity to the ground and are fully exposed to the roots and rocks of the trails. The internal gearbox system is, therefore, a solution to these inevitable mechanical faults. This adds on to point #1 on low maintenance. 

 

Notice how the chain in a traditional drive train system is situated very low and close to the ground. Source: enduro-mtb.com

 

In comparison to… 

 

The gearbox system. There is a higher clearance of the chain from the ground.

 

 Unlike the traditional drivetrain system, the chain on a gearbox system will never be in contact with the ground because the tensioner is situated in the front and higher from the ground instead of at the back. This position also prevents chain slapping, making it a quieter system to ride with.  

 

#3. Improved Centre of Gravity 

Having the gearbox in the middle of the bike where the bottom bracket is usually located means that the weight of the bike is now shifted from the rear wheel to the centre. For a traditional drivetrain, the rear derailleur and cassette makes the bike heavier at the back.

The centre of gravity of the bike is optimised, so every time you corner or go downhill, you are rewarded with a stable ride. The back wheel feels lighter and you can feel the bike as you are navigating through the trails. 

 

 

#4. Wider Range and Ease of shifting 

This shifting system works similar to a motorbike. The Gearbox system uses grip shift instead of the traditional trigger system. You can change gear without putting a pedal stroke in. This feature is especially useful when climbing up hills; you will never get caught in the wrong gear. Even if you find yourself in a wrong gear at the bottom of the mountain, quite flick of the wrist, and you’re suddenly in the right gears, and you can pedal off. 

 

READ more:  How to fix puncture and mend inner tube

 

In comparison to the SRAM-Eagle which only has a gearing range of 500% (gear ratio 10-50), a gearbox system can accommodate a gearing range of 600% (gear ratio 10-58). Being able to switch to a lower gear also means that this system can accommodate both newbies to advanced mountain bikers. 

 

#5. No suspension “lock-down”

The gearbox system also allows the bike manufacturer to build a suspension system that is not constrained by the current drivetrain designs.

In a traditional drivetrain system, when you press on the brakes, the chain pulls on the suspension and locks it. Compared to a gearbox system, the chain still moves around with the link. This is an advantage especially when you go downhill as your suspension is still fully active even when you are pressing on the brakes. 

 

 

#6. Zero pedal kickback

Zero pedal kickback refers to the rotational movement of the pedals backwards as the suspension impacts. On a normal mountain bike, your legs are constantly absorbing the rotational pedal impact. The Deviate Guide manages to eliminate the pedal kickback, giving you a solid platform when descending. This reduces fatigue, you don’t get a jarring motion of fighting the suspension action as you are pedalling in the trails.  

 

“The bike takes care of the impacts behind you, allowing you to concentrate on picking your line”

 

 

Conclusion

The Gearbox system is definitely an up and coming technology in the mountain biking world. However, you need to know how to operate a gearbox system before making the switch, as it uses a gearshift instead of the trigger shift on a conventional drive train. Furthermore, it will take a bit longer for brands to adopt this system. You are unable to install the gearbox on any bike frame because it is built into the frame, which is the reason why very few bike manufacturing companies are producing this type of frames.

Overall, the gearbox definitely triumphs as it still accommodates a comparable gear range and capabilities of a conventional drive train, while providing increased protection, strength, durability, and performance.

 

Stay tuned to our next article where we feature this full carbon gearbox bike- The Deviate Guide.

 

 

Special thanks to Gio, Robert, and Sam from BYX

Esther Koh

Author: Esther Koh

Cycling is her drug and therapy.
She is a certified Nutritionist (BSc Nutrition, University of Leeds) and loves both road cycling and mountain biking. She hopes that more females in Singapore will discover the joy and simple pleasure of riding a bike.

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