Microshift Advent Super Short Drivetrain Review

As I mentioned in my review of the Velo Orange Neutrino, selecting an appropriate drivetrain for a tiny 20″ wheeled bike isn’t as straightforward as one might think. It’s a balancing act of finding proper gearing for how you ride, which in my case includes some off-road riding, while also ensuring you have proper ground clearance so as not to rip off a derailleur on the first root or rock you encounter.

Lots of Neutrino owners take advantage of shorter road bike drivetrains, internally geared hubs, singlespeed setups, and enduro derailleurs like Shimano Saint and Zee, and they work. But, in some cases, they aren’t totally ideal for off-road riding. Earlier this year MicroShift launched their new Super Short mountain bike drivetrain for 20″ kids bikes and it immediately caught my attention as a promising option for my dream Neutrino build. Unlike most kids drivetrains, MicroShift promised proper chain retention, durability, a wide-range cassette, as well as lighter shifting and shorter reach for small hands.

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Microshift is in the business of drivetrains, prioritizing quality and adaptability, and the Super Short range is no exception. According to Microshift, kids bikes are outfitted with nice tires, modern geometry, high-end suspension, but drivetrains haven’t caught up yet, which is why they introduced Super Short. The range is offered at two levels: Advent and Acolyte. Advent is the top-end group, based around nine-speed system with an 11-38T range and a derailleur equipped with a ratchet-and-pawl clutch. Acolyte is an eight-speed system with an 11-38T cassette and a non-adjustable spring-powered chain retention on the derailleur. Both cassettes in the range use standard Shimano HG freehubs, not freewheels like some kids bikes, and have an 11-13-15-18-21-24-28-32-38T gearing breakdown. All components are available to purchase on their own and match up with standard nine-speed chains, which are strong and readily available.

I was most interested in the Advent Super Short’s adjustable clutch system and was able to get my hands on the entire Advent group for my Neutrino build. There are a few different shifter options, but I ended up with the Quick Trigger Pro, which has no visual gearing indicator but is finished with a nice rubber pad on the thumb lever for better grip.

Advent 11-38T Cassette

At the heart of the Super Short system is a nine-speed 11-38T cassette. The cogs are made from stamped ED-coated steel, the smallest two are removable, and the rest of the cassette is pinned together. According to Microshift, pairing the 38T cog with a 20″ wheel results in a low gear that feels like a 52T low cog on a 27.5″ wheel bike. For example, calculating the gear inches afforded by my easiest climbing gear (42T ring + 38T cog) is right around 20 gear inches, while my hardtail (30T ring + 51T cog) has 17 gear inches. As far as climbing goes, 20 gear inches isn’t that bad. On the high end, the Neutrino has 69 gear inches with the setup I tested, and my hardtail mountain bike with a modern 12-speed setup has 87 gear inches. In short, you’ll make it up climbs, but don’t expect to get anywhere else blazingly fast.

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Anyone riding off-road, especially younger riders, will greatly benefit from the lower range offered by the larger cassette, giving them a fighting chance to get up steeper pitches and trails. To offer some comparison, most kids bikes come specced with 34T or smaller cogs on the cassette, often paired with grip shifters, since that that used to make the most sense for smaller hands. Not any more. It’s a a beast of a cassette at 487 grams, but it gets the job done.

As far as gear progression goes, it’s no surprise to see bigger jumps between gears compared to 11 and 12-speed systems. However, on the low end, these jumps aren’t that far off from the 12-speed drivetrains I normally ride, making the progression between shifts feel familiar enough not to bother me. I never had issues jumping up from the 32T cog into the 38T. Keep in mind that the Acolyte Super Short 8-Speed cassette has even bigger jumps between gears, with an 11-13-15-18-21-24-30-38T progression vs. the Advent’s 11-13-15-18-21-24-28-32-38T.

• Gear Range: 11-13-15-18-21-24-28-32-38T
• Material: Steel
• Weight: 487 grams
• Place of Manufacture: Taiwan
• Price: $32.99 USD
• Manufacturer’s Details: MicroShift.com

Super Short Clutch Derailleur

The Super Short Advent Clutch Derailleur packs in a lot of nice features. It has a proper steel and aluminium construction that feels solid and can take a hit or two. It uses the same build quality and design as their full-sized Advent and Acolyte groups, including reinforced link rivets and a cage length that is 50mm shorter than the full-sized derailleurs for proper ground clearance with little wheels.

The Super Short Clutch Derailleur is equipped with a proper ratchet-and-pawl clutch for chain retention that’s said to be easily repairable. It’s turned on and off using a simple on/off switch, and for the most part, it does a good job at keeping proper tension on the chain so it’s not bouncing around too much while riding off-road. I did notice a slight lag before the clutch really kicks in, so there’s some bouncing around before the mechanism actually holds on the chain tight, but it’s not bad considering it’s designed for kids bikes.

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Adjusting the clutch mechanism is straightforward. Two screws hold the clutch cover in place and a T15 Torx wrench tightens its assembly bolt a quarter turn at a time to increase the clutch strength. You simply push the derailleur forward by hand to test it. All of the parts, including the pawl and ratchet assembly are broken down on the Microshift website in exploded diagrams, and are available to purchase for full derailleur rebuilds. For a better look at how their clutch system works, check out the short video below.

• Material: Steel, Aluminum, Plastic
• Weight: 360 grams
• Place of Manufacture: Taiwan
• Price: $64.99 USD
• Manufacturer’s Details: MicroShift.com

Super Short Quick Trigger Pro

Having sold my fair share of youth bikes while working in a shop, I could see the Super Short shifters as a game changer for many kids or anyone with small hands. Compared to the competition, the Super Short Trigger shifter has a 43% shorter lever throw (around 20mm versus the 35mm of the competition). It’s a noticeable change, even for someone with big hands, and makes for an incredibly light shifting action that feels high-end. It has an aluminum bar clamp, and the rest of the shifter is mostly plastic. On the Trigger Pro version I’ve been using, the thumb lever is finished with a grippy rubber pad, which is really nice to see. The overall look and feel of the shifter had me forgetting I was using a drivetrain designed for kids bikes.

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If I had to compare the shifter feel against other drivetrains, I’d say it feels closer to SRAM 12-speed systems than Shimano 12-speed. There’s a familiar smoothness with each shift that feels less mechanical than Shimano shifters, but at the same time, there’s no second-guessing whether the gear change will happen, as it has a very positive lever action.

It’s worth noting that like their other components, the Advent Super Short derailleur and shifter are only compatible with Advent lever throw, so you might run into compatibility issues when trying to mix and match parts. That being said, the entire groupset works well together and is quite affordable, so I think it makes sense to run the complete set.

• Material: Aluminum, Plastic
• Weight: 123 grams
• Place of Manufacture: Taiwan
• Price: $27.99 USD
• Manufacturer’s Details: MicroShift.com

• Gear Range: 11-38T
• Speeds: 9-Speed
• Weight: 970 grams (cassette, shifter, derailleur)
• Place of Manufacture: Taiwan
• Groupset Price: ~$165 USD
• Manufacturer’s Details: Microshift.com

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