Specialized Jett: adjustable kids’ bike uses Retül data to fit ‘better for longer’

Not only do kids deserve class-leading bikes, but they also deserve a bike that fits better, for longer, according to Specialized, and that’s why the US brand has worked with Retül – who it calls the cycling industry’s best bike fitters – to develop the new Jett.

The Jett is a range of four models in three sizes – with 16in, 20in and 24in wheels – but Specialized has built 30 months of growth into the adjustability of each size in the form of 2-hole positions for cranks, a long seatpost, and adjustable handlebars for extended reach.

Additionally, Specialized has designed kid-sized components such as a specific saddle, narrow q-factor cranks for better hip-knee-ankle alignment, narrower grips and short-reach brake levers.

Specialized says parents told them they wanted a bike that fits their kids for about 30 months or three summers. According to its research, kids aged 5-12 grow in their arms and legs faster than their torso. So its aim was to make a bike that was proportional and adjustable for quickly-growing arms and legs to achieve the perfect fit multiple times in the bike’s lifetime.

“We developed the Jett using the same study tactics that we use with world-class athletes, says Specialized. “During ‘Bring Your Kids to Work Day’ at our Boulder, CO office, we gathered data from our own kids.

“The team put kids on bikes and observed the mechanics of how they were riding. Were their knees aligned in their pedal stroke? Are their shoulders stacked properly? Which kids could reach the handlebars most easily? Are the components compatible for their size?

“The data collected was optimised in the design process to increase comfort, eliminate common pain points, prevent future injuries, and improve the rider’s potential to perform on the bike.”

Specialized says the Jett is “a quality ride that weighs in at just 9.39kg/20.5 lbs (24in), enabling riders to keep up with the grown-ups or lead the pack.”

All four bikes are based around an ‘A1’ aluminium frame. Their seatposts are about 60mm longer than the seatposts typically stocked on kids’ bikes according to Specialized. For example, the Jett 20in has a 280mm seatpost.

Specialized Jett 16 Single Speed

The Specialized Jett 16 is aimed at children between 95cm-121cm. Specialized says that because it is focused on fit and skill level, parents are invited to select bikes based on the height and skill level of their rider.

The 16in Jett runs a 26x16 ratio, has V-brakes with tool-less reach-adjust levers, a 130mm Bridge saddle and a KMC anti-rust chain.

It rolls on Pathfinder Sport 2.0in tyres, which should be bombproof for any type of terrain.

There’s no weight supplied for the 16in bike. RRP £319.

Specialized Jett 20 Single Speed and Multispeed

The 20in-wheel bike is available as a singlespeed or seven-speed geared depending on the child’s ability and is for a height range of 102-132cm.

The singlespeed version gets a 34x18 ratio while the geared bike runs a 34t chainring and an 11-30 cassette.

As with the 16in, it’s specced with V-brakes with levers that are tool-less adjustable.

The geared bike gets two-hole cranks for adjusting crank length between 105mm and 125mm.

Both bikes get Pathfinder Sport 2.0in tyres

Claimed weight is 8.76kg or 19.3lb for the multispeed bike. RRP is £369.

Specialized Jett 24 Multispeed

For children from 109cm-147cm there's the eight-speed Specialized Jett 24in.

It comes with longer adjustable cranks (130mm-150mm) but the same gearing with a 34t chainring and a good spread of gears via the 11-30 cassette.

Like the other Jetts it’s shod with Pathfinder Sport 2.0 tyres.

Claimed weight is 9.39kg/20.5lb. RRP is £419

The prices are more or less in line with Specialized's competitors, such as Giant with its ARX range (read our review of the Giant ARX 20 here) while Islabikes, arguably first with kid-specific components, prices the 24in Islabikes Beinn higher at £549.99.

Find out more about choosing and buying children's bikes with our comprehensive guide here.