Reebok GT40z Treadmill Review: 18km/h and a 10-Year Motor Warranty for £549

The Reebok GT40z is a good treadmill for walkers, incline walkers and steady joggers who weigh under 100kg, and at £549 it's one of the better-backed machines in this price band. You get an 18km/h top speed, 12 levels of powered incline, Zwift and Kinomap support and a 10-year motor warranty. What holds it back is the 110kg user limit and a 130cm deck that tall runners will find short once the pace goes up.

That's the summary. The rest of this review explains who should buy it, who shouldn't, and how it stacks up against the other Reebok and value-brand machines we've covered.

Who the GT40z is for

Picture someone who walks most days, jogs two or three times a week at 8 to 11km/h, and wants an incline button for hill work. This machine was built for that person. The 2.0HP motor is comfortable at those speeds, the 12 powered incline levels make treadmill walking much harder work than flat walking, and the console has enough programmes that you won't get bored inside a month.

It also suits anyone using a treadmill to hit the NHS target of at least 150 minutes of moderate activity a week (NHS physical activity guidelines for adults). Brisk incline walking is moderate activity for most people, and doing it indoors removes the British weather as an excuse.

Who should skip it? Heavier users and taller, faster runners. If you weigh close to 110kg, you'd be running the motor and frame at their rated limit every time you step on. And if you're over about 180cm and want to do interval sessions at 14km/h or faster, a 130cm deck will shorten your stride or have you drifting towards the back roller. Either group will be happier spending more, and our best treadmill under £1000 guide covers the step up.

Check price on Amazon£549.00

Motor, speed and the 110kg limit

Reebok lists the motor as 2.0HP. That's the right size for walking and jogging, and it'll handle the odd faster session without fuss. For someone running 40 to 50km a week at a steady pace, though, a 2.0HP motor is working harder than a 3.0HP or AC unit would, and harder work over years usually means a shorter life. The listing doesn't say whether 2.0HP is a continuous or peak figure, and that distinction matters for sustained running, so treat it as a ceiling rather than a guarantee.

The 18km/h ceiling is the GT40z's best number. Reebok's own i-Run 5.0 tops out at 15km/h, and 18km/h covers sprint intervals for almost every recreational runner. Our guide on how fast treadmills go explains why most people never need more than 16km/h, so this is headroom rather than a necessity.

Now the limit. A 110kg maximum user weight is on the low side. The i-Run 5.0 is rated at 120kg for £100 less, and the KITOPA we reviewed claims 180kg. Body weight matters more on a treadmill than on a bike because each footstrike loads the deck, belt and motor at a multiple of your weight. If you're 95kg and running, you're already in the upper part of the GT40z's comfort zone.

Deck, cushioning and running feel

The running area is 45 x 130cm. Width is adequate; 45cm is a little narrower than the 51cm on Reebok's FR30z, but you won't feel boxed in at walking pace. Length is the bigger question. Walkers and joggers won't notice it. Runners will, because stride length grows with speed, and a 130cm belt leaves less room for error at 14km/h and above than the 150cm decks you'll find around £900.

Reebok uses its "One series" cushioning here. The company doesn't publish a technical breakdown of how it works, so treat it as a standard elastomer-style system rather than anything special. Owner feedback generally describes the deck as firm but comfortable, which is what you'd expect at this price.

Will running on it feel different from running outside? Less than you might think. A systematic review and meta-analysis of 33 crossover studies found most biomechanical outcomes were largely comparable between motorised treadmill and overground running, with the clearest differences in foot angle at footstrike (Van Hooren et al., Sports Medicine). That backs up what most coaches already tell runners: a treadmill is a perfectly good place to build fitness.

Incline and programmes

Twelve powered incline levels is a big draw for walkers. Walking uphill raises the energy cost of each minute considerably compared with flat walking at the same speed, which is why routines like the 12-3-30 workout have become so popular. On the GT40z you can raise the incline from the console without stopping, and that's what makes a 30-minute incline walk practical.

One honest gripe: Reebok lists incline as levels, not a percentage gradient. Without a percentage you can't compare it directly with the KITOPA's 18% or follow a plan that asks for "12% incline". Expect to experiment a little and judge by heart rate or effort instead.

The programme count is generous. Thirty-six presets, three target modes (distance, time or calories), three user profiles for a shared household and a body fat estimate from the hand pulse sensors. We'd take the body fat reading with a large pinch of salt, as hand-grip estimates are rough at best, but the presets do a decent job of varying speed and incline for you.

Console, apps and extras

The 5in blue backlit LCD shows the basics: speed, time, distance, calories, incline and pulse. It's clear rather than fancy. There's a tablet holder above it, a speaker with MP3 input and a cooling fan, which is weak on most treadmills and probably no exception here.

Zwift and Kinomap support is the more useful extra. Both connect over Bluetooth via a dongle, so you can run virtual routes or races with your tablet as the screen, and a 60-day Kinomap trial is included. Do note that the GT40z doesn't have a built-in touchscreen; if you want that experience, you're into NordicTrack territory and a much higher price.

Folding, size and warranty

In use the GT40z measures 168 x 77 x 134cm. Folded, it's 103 x 77 x 146cm, so it stands upright and saves about 65cm of floor length rather than vanishing under a sofa. The Soft Drop system lowers the deck under control, which matters with a 61kg machine, and the transport wheels let one person roll it into a corner. If you need something that slides under a bed, look at our best fold flat treadmill UK guide instead.

The warranty is where the GT40z earns its price. Ten years on the frame and ten years on the motor for home use, plus two years on parts and labour, is strong cover for £549. The KITOPA offers five years on parts and motor; many budget brands only give one or two years on everything. Parts and labour at two years is standard, so belts, consoles and incline motors are on you after that.

Check price on Amazon£549.00

Reebok GT40z vs the alternatives

Reebok i-Run 5.0 (around £449). The closest sibling. It has 12 powered incline levels and Zwift and Kinomap support too, and a higher 120kg user limit. The trade-offs are a 15km/h top speed, a 120 x 46cm deck and a 2HP peak motor. The GT40z gives you 10cm more belt length and 3km/h more speed for £100. If you run at all, that's money well spent; if you only walk, the i-Run 5.0 does the job.

KITOPA Foldable Treadmill (around £470). The KITOPA wins on numbers: 18% auto incline, 20km/h and a claimed 180kg limit. Its 120cm belt is shorter than the GT40z's, though, and KITOPA doesn't publish a motor rating. We'd pick the KITOPA for heavier walkers who want steep incline, and the Reebok for runners who value the longer deck and a known brand's 10-year motor cover.

Reebok FR30z Floatride (around £899). If your problem with the GT40z is the 130cm deck or the 110kg limit, this is the answer. It has a 150 x 51cm deck, 15 incline levels and a 150kg rating. It costs £350 more, and for walkers that extra spend buys very little.

For a broader look at the category, our best treadmills for home use roundup compares machines across every budget.

Recommended reads

• Best treadmill under £1000
• Reebok i-Run 5.0 treadmill review
• KITOPA treadmill review
• Best incline treadmill UK
• The 12-3-30 workout explained