Among the groupsets that Microshift proudly offers—"ADVENT X," "ADVENT," and "ACOLYTE"—the ADVENT and ACOLYTE series feature a rear derailleur with a "Super Short Cage" that many may not be familiar with.
As the name implies, it is a rear derailleur with an exceptionally short cage, and I would like to delve a little deeper into why such a component is necessary.
The rise of giant sprockets and the long cages required to match them
As exemplified by the popularity of gravel bikes, more and more bikes these days are designed for rugged terrain. Off-road paths often feature steep climbs that you don't find on paved roads. Consequently, rear sprockets have been growing larger and larger to help riders tackle any steep incline, with monster-sized options like 51T or 52T sprockets—even larger than disc brake rotors—now hitting the market.
I’m not saying that’s a bad thing. For a rider with weak legs like myself, these sprockets are a lifesaver—enough to make me want to coin the phrase, "Thank goodness for that 50T."
On the other hand, large sprockets require a rear derailleur with a long cage.
The weakness of giant sprockets and long cages
However, from a mechanic's perspective, it is a fact that this combination of a large sprocket and a long cage can make certain bicycles difficult to use. Which bikes, you ask?
Simply put: small-wheeled bikes and children's bikes.
In other words, bikes that use smaller wheel sizes. What problems arise when you use a giant sprocket on these?
The importance of clearance
The issue is the lack of distance from the cage, caused by the small wheel diameter.
- Distance from the ground
- Distance from the tire
These two distances, in particular, become major bottlenecks.
Distance from the ground
A giant sprocket is, naturally, very large in diameter, and when installed on a 20-inch bike, it has an overwhelming presence. In such cases, there is often only a few centimeters of space between the rear derailleur and the ground.
It isn't actually touching the ground, and it would be very difficult to strike the derailleur even when leaning the bike during cornering, so you could say it isn't a problem. Still, the chances of hitting curbs or obstacles increase, and the size balance with the frame isn't ideal.
Distance from the tire
The lack of clearance isn't just vertical; it exists horizontally as well.
The derailleur cage, when shifted to the lowest gear, sits right beside the tire, and even with the relatively narrow tires of a small-wheeled bike, that gap is paper-thin.
One might argue that as long as it isn't touching, there’s no problem, but that lack of clearance is still unsettling.
Use a dedicated small derailleur for small-wheeled bikes
That is precisely why I believe the Super Short Cage is the solution to these issues of imbalance and tight clearances. While the maximum sprocket size you can use drops to 38T, all these problems are resolved, and you are no longer bothered by the awkward visual balance.
Do easy-to-pedal small-wheeled bikes even need giant sprockets?
Using a smaller sprocket means you lose your easiest gear, but this can be compensated for by changing the size of your front chainring. After all, small-wheeled bikes are easy to start pedaling with, so a 38T sprocket is more than enough.
Beyond resolving the visual imbalance, this system is a perfect match for small-wheeled bikes and children's mountain bikes that are used off-road. Compared to on-road riding, chain slap and vibrations are much more frequent off-road; if the rear derailleur is too close to the tire, there is a risk that the chain could get caught, rendering the bike unusable. The Super Short Cage helps alleviate the anxiety caused by these types of troubles.
A lineup only Microshift could provide
This Super Short Cage may be quite limited in its application and benefits, but it’s a quintessential Microshift item that scratches an itch you didn't know you had. It might not be for everyone, but I’m sure there are some of you who have been waiting for exactly this. I wrote this article hoping it would reach those of you who need it.
Please feel free to consult us about upgrading to a Super Short Cage.
MICRO SHIFT Advent Super Short Cage Clutch Rear Derailleur
