Prevelo Alpha Three 20-inch

The Prevelo Alpha Three 20-inch is a great choice for young riders moving up to a geared bike with larger size wheels. With its smart design and sizing, it offers a low standover height that suits younger kids earlier than bikes from many other brands. In addition to the well-considered frame, you also get well-chosen components, including custom parts designed for its target riders. Thanks to this mix of sensible geometry, good design and quality parts, both of my children have found it a confident, lightweight and fun bike to ride.

Prevelo is a US-based company dedicated to making kids' bikes, similar to Early Rider and Islabikes. Its range is easy to understand with three main models: Alpha, Zulu, and Bravo. The Alpha is an all-purpose bike, the Zulu is made for off-road riding, and the Bravo is built for Dirt Jump.

Each range increases with wheel size, starting with the 14in balance bike called Zero, and going up through common sizes to 26in with the Alpha and Zulu Five. The Alpha Three, which we tested, is the 20in wheel model. It's designed as an all-purpose bike and features components, like the tyres, that will also cope with some unsurfaced riding.

Sizing

Prevelo recommends the Alpha Three 20-inch for riders with an inseam of 19-23in (48.3-58.2cm) or a height of 42.5-49in (108 to 125.5 cm). I have one child at each end of this size range and I was able to see how both of them, despite their different riding styles, felt confident on the bike.

My youngest, who is just within the size range, needed the saddle near its lowest position. He's a confident rider and enjoys participating in local events but struggled with his Vitus 16in single-speed bike in our hilly area. Moving to gears required a 20in bike, but most 20in bikes don't offer the standover height he needed.

Even in the lowest position the Alpha Three fitted him well – he wasn't overly stretched, and the handlebar width suited his riding style. Being able to switch to a bike with a usable gear range and a comfortable fit has significantly expanded where we can ride together and increased his enjoyment of cycling in new places.

My daughter is at the upper end of the size range and already rides a 20in bike with gears. She found the Alpha Three comfortable and we managed our longest ever riders in complete comfort, but I'd consider fitting a longer stem to extend the reach for her if this was her main bike.

Frame and fork

The Alpha frame is crafted from 6061 aluminium alloy with custom-forged tubing and it's paired with an aluminium fork featuring an alloy steerer. It features internal cable routing, with the rear brake and derailleur cables entering near the headset. These full outer cables are designed to last longer and avoid snags.

The frame's geometry provides ample standover clearance, with a minimum saddle height of 21.2in (540mm). The Alpha Three has a bottom bracket height of eight inches (205mm) and a 1.5-in (38mm) bottom bracket drop, which is lower than many other 20-inch bikes. This low standover height is a key reason shorter riders can comfortably fit the bike, although it limits the upper height range.

Other notable features include an Aheadset and a sculpted 3D-forged rear dropout, which may contribute to the bike's low weight.

Key geometry figures include a 69° head angle and a 71.5° seat tube, which suit the bike's multi-purpose design.

Drivetrain & components

Prevelo is one of the companies that has helped drive the market and push suppliers, and the microSHIFT Acolyte groupset fitted to the Alpha Three is one area that shows how the market is moving, as it is specifically designed for youth bikes.

The Super Short Cage version is an 8-speed groupset with a wide-range 11-38T cassette designed to fit 20in wheels.

The shifter is also designed for smaller hands, with a short reach, and neither of my children had problems with the distance or the force needed to push to an easier gear or reach the click to move to a harder gear.

It can change up to three gears in one push, although the second and third gears require a significant push, with the third beyond what I could do comfortably.

The groupset is finished with Prevelo's own-brand Heir chainset, with 110mm cranks and a 138mm Q-Factor, figures that make it suitable for smaller riders. While other brands are also beginning to shorten their cranks, this is still among the shortest you'll find on a bike with 20in wheels. Crank length is important for comfort and pedalling efficiency, and the Prevelo's is around the same percentage scale as crank lengths on an adult bike.

The 32T chainring helps to deliver a usable gear range, with the easiest gear well below a 1:1 ratio. That said, if I were to pick any size I'd go for a 28 or 30T ring, as it did require quite an effort to use the highest 11T cassette.

The rear derailleur is not fitted with a SpringLock clutch system.

But despite using the Alpha Three on and off-road the chain didn't come off at any point, no doubt helped by the chainguard on either side of the chainring.

Wheels & tyres

The wheels are fairly simple, their 20-spoke count keeping the weight reasonably low. Out of the box they were very slightly out of true, but this didn't worsen with use.

I did need to adjust the preload tension on the rear wheel bearing, which initially had significant drag that seemed like a brake pad issue.

It was a quick fix, but it's not something everyone might know how to do or have the tools for, and it's not something you'd expect on a new bike. One small touch that might be to help save weight and simplify the build is the use of hex-key bolt-on axles.

The tyres are 1.5in Kenda Small Block Eights. Their tightly packed tread is a popular choice for youth bikes and works well on the variety of terrains the bike is intended for, including surfaced tracks and firmer off-road trails. However, they do slide on wet grass and quickly clog with mud, and there are better options for frequent use on such surfaces.

During testing, the bike was also used in several race events, and we found there was impressive clearance at the front, with a 20x2.25in WTB Ranger just fitting under the fork crown. The rear doesn't have the same clearance, but a Schwalbe Black Jack 20 x 1.9in did fit with ample mud clearance. These tyres do push the boundaries of what the bike is designed for, and the Prevelo Zulu Three would be better suited for mountain biking.

Controls and finishing kit

The Tektro brake levers can be adjusted for a very short reach and, combined with the Tektro V-brakes, they provide ample stopping power.

The brake pads themselves are okay, and if you have a demon descender, swapping these for a grippier pair will make a significant difference.

The handlebar has a 45mm rise and is 560mm wide, suiting the all-round style the bike aims for.

Both the stem and handlebar have a standard 31.8mm diameter, making any changes easy and affordable. The rubber grips are very thin, the slimmest I've seen on any bike, allowing smaller hands to hold onto the bar. This has been particularly important for my children when braking and gripping, though the potential downside is reduced comfort on longer rides.

I've received no complaints about saddle comfort, and their low rails are paired with an inline seatpost that for a low overall minimum rider height.

The quick-release seatpost clamp is a welcome addition, allowing quick height adjustments between children or for different riding styles.

The short 45mm stem is great for smaller riders, and with the frame geometry, both of my children found it confident and easy to ride. However, taller riders near the upper end of the recommended range might benefit from a longer stem.

The pedals, while not rolling very well on the axle, feature good grip studs in the plastic, which help keep the soles firmly in place.

Value

As recently as five years ago, only a handful of companies offered bikes with genuinely thoughtful designs and bespoke components.

Many credit Islabikes with pioneering this change in the market. Although it stopped making new bikes in 2023, its recent announcement to continue providing spare parts ensures its bikes remain in use. The comparable Islabikes model was the Beinn 20, available in small and large reach versions, highlighting the broad age and size range for a bike with 20in wheels.

The Prevelo Alpha Three has a claimed weight of 8.1kg (17.8lb) and came in very marginally weightier at 8.3kg (18.3lb). At £569.99 it's much dearer than the Vitus 20, which costs just £349.99. However, the Vitus's geometry is better suited to taller riders, starting from 120cm (3ft 11in), and it has a lower specification with a Shimano Altus 7-speed groupset. Weight is a claimed 8.5kg.

Among major brands, the £425 Giant ARX 20 has a similar all-purpose build, accommodating a height range of 120-140 cm (3ft 11in to 4ft 7in), and features a Shimano Altus 8-speed groupset. However, there are some notable differences, such as longer 127mm cranks and there's a lower gear range courtesy of its 12-32 cassette.

The updated Trek Wahoo 20 Path is the closest equivalent from the big brands, with a competitive price. It also features the microSHIFT Acolyte 8-speed groupset, with a suggested minimum height of 114cm (3ft 9in). While it is £145 cheaper at £425, the claimed weight of 8.7kg would make a difference for smaller riders.

Our best kids' bikes buyer's guide covers children's bikes from balance bike upwards.

Conclusion

The Prevelo Alpha Three 20-inch offers a specification and geometry that elevate it above many other all-round children's bikes. Its fit and low standover height make it an excellent option for smaller children ready to transition to a geared bike. The components are well chosen, and Prevelo's Heir own-brand parts have made it a very confident ride for both of my children. However, while not all major brands focus on high-performance kids' bikes with bespoke components, some do, which makes the Alpha Three's high price – at least at full whack – harder to justify.

But if you're a parent looking for the best all-round 20in children's bike, or simply know your child is ready to step up to gears – like my son – the Prevelo Alpha Three 20-inch remains a top choice, especially if you can get it at a reduced price.

Verdict

Excellent specification with size-specific parts and geometry that make it a confident bike to ride for younger riders