Disclosure:  Cycle Sprog were sent the Cube Acid 240 to review. We were not paid to write this review, and all opinions are our own. We do use affiliate links, so may get a small commission if you choose to buy through the links on this page. This funds the website, and we thank you for your support.

Cube Acid 240 review

About our reviewer

Rosie was 9 at the time of testing, she had just grown out of her Isla Benin 20, which had been great for riding around town and on forest roads. When she started riding the bike, Rosie was 133 cm and is now 135 cm.

As well as looking to get her onto a larger bike, Rosie's parents were also keen to see how a mountain bike and suspension would help her gain more confidence to tackle different terrain whilst also allowing her to enjoy cycling on the roads around town.

Rosie had also just grown out of her helmet so Cube sent their Cube ANT helmet a test as well as a little Cube riding bag. 

Cube offers a diverse range of kids' bikes, designed to suit various riding styles and skill levels. At the entry-level of their mountain bike lineup is the Cube Acid series, which is the focus of this review.

The Acid is designed for young riders starting to explore off-road trails, featuring front suspension, disc brakes, and a robust build. For more advanced mountain bikers, Cube offers the Elite series with lighter frames and upgraded components, while the Stereo range is for aggressive riders tackling technical terrain, boasting full suspension and enhanced geometry.

Alongside their mountain bikes, Cube also provides the Nuroad series: a lightweight hybrid option designed for kids who need a versatile bike for urban commuting and smoother surfaces. Cube’s range ensures there's a bike for every young cyclist, from casual riders to budding adventurers.

Rosie immediately liked the striking black appearance. She initially couldn’t reach the brake levers, but it was really easy to adjust the reach, which took less than a minute to do.

She had been apprehensive about using the disc brakes as she’d heard they were really good for skidding (Dad’s fault) which she doesn’t like to do. However, she’s really liked the brakes and they work very well. She is able to confidently manage her speed and avoid skids!

The next day after collecting her test bike Rosie took it to school for a Bikeability session, where the bike went down well with the keen mountain biking crew of kids. So if schoolyard looks are important, this bike certainly ticks the box there.

On the downside, Rosie did find the increase in weight a bit of a problem as she couldn’t immediately lift the bike up steps. Her old bike was around 8kg, whereas the Cube weighs 13kg as tested with the kickstand.

Riding the Cube Acid 240

Rosie has ridden the bike for about 6 months now, so has really been able to test how she likes to ride. This has ranged from gravelly forest tracks, rocky bridleways, some single track, and grassy parks. These have varied from 2-4 km rides in town to 10-15km rides out of town. To help with snack independence she added a little top tube bag and that fitted nicely. The one place Rosie hasn’t tested it - where we think it could be taken by a lot of users - is at a bike park or pump track. 

Throughout the test period, there has been no issues with the bike and it seems a great reliable bike. The only damage has been that one of the reflectors dropped off! The bike is easily small enough to fit in a car boot with the front wheel off, which as you’d expect is very easy to do. 

Off-road is where the bike really comes into its own. The tyres get great grip, the gears provide good ratios for steep up hills, the suspension helps soften bumps and the heavier weight of the bike gives confidence while descending, removing the 'skitting' feeling of bouncing between rocks.

The bike performs well on tarmac, retaining its grip on leafy, greasy park flooring as well as providing reassurance with its MTB geometry. Over the testing period, Rosie has gotten more used to how much effort she needs to use to build up speed and use the gears to go fast on the flat.

Rosie was very keen on the kickstand that the bike was provided with, which works well and comes in handy with the stop and start nature of Rosie’s riding.

Front Suspension

The Cube Acid 240 Disc comes equipped with SR Suntour SF20 XCT JR, 60mm forks which are coil-sprung, rather than air. This means they are heavier and require more bumpy terrain and heavier weight of rider for them to compress, but they are a cheaper option that requires less care and maintenance. 

At first Rosie didn’t think they moved at all, but later on she realised that they were doing their job.

Suspension on a child's mountain bike is always a weigh-up of pros and cons, you will need to consider a balance between your budget, the intended use of a bike, the weight of your child, the weight of the bike, and aesthetics.

Bikes with air suspension such as the woom OFF Air 5 and the Frog 62 are in a higher price bracket to this Cube Acid 240, but are lighter, and the suspension will be more responsive on bumpy terrain. Or there's the option of a rigid fork with large volume tyres, that might give your child enough suspension on easy off-road terrain. Check out our guide to buying a kids mountain bike for more information.

Rosie is comparing these forks with the air suspension (Spinner Grind Air 50mm) her younger sister is using on the Black Mountain Hutto bike; these do respond much better to lower weight riders (~25kg). These undoutebly absorb the bumps in the trails more than the Cube's forms, which would be expected for comparing air to coil sprung forks.

Rosie’s view is that it certainly is - “you feel like you are floating” - which is one of the best feelings on a bike- so they get a positive review from Rosie!

Geometry

The short stem and wide handlebars mean that Rosie is confident handling the bike and steering around obstacles.

The Cube Acid 240's geometry appears to strike a good balance between relatively upright (by today’s super-slack styles) and slack head angle. This makes it good for longer family rides where Rosie likes to sit up and pedal. However, at the same time as testing this bike, Rosie's 6-year-old sister has been riding the Hutto 20 inch Mountain bike, which has a much slacker geometry and really seems to make a difference on the descents.

This bike is therefore brilliant for children wanting to ride a variety of terrain, but perhaps not ideal for someone looking to progress onto technical mountain bike trails, jumps and drops.

Weight of the Cube Acid 240

For Rosie the weight of this bike was initially a bit of a challenge, for example she found it hard to manoeuvre between bike gates (as she has to reposition her hands to drag the back end round and pull quite hard). She’s been unable to take the bike up steps.

Whilst this has made it harder for Rosie most of the time, the extra weight can provide advantages, as it helps lighter riders on rougher ground by holding the line better and avoids the bike skitting around over bumps. I was certainly pleasantly surprised by how confident Rosie was riding down rougher bridleways. 

The weight of the Cube is on the heavier side compared with other bikes in this price bracket at 13kg. For example, the top of the range Woom OFF AIR 5, and Frog 62 bikes also reviewed by Cycle Sprog are 10.3kg and 11.3kg respectively. In the less high end category of mountain bikes, the BTwin Rockrider ST900 24" wheel MTB at £349 is 12.29kg and the Cannondale Trail 24 Plus at £470 weighs 11.6kg. 

Thoughts from the Sprog

Overall the bike’s really good. The gears are really good to use and turn really easily. The brakes are very very good brakes and they stop you really quickly. They work really really well. The suspension took a while to kick in but now it's really helpful. When I come off some rocks when we go mountain biking or a curb or something like that it makes it quite smooth and like you are on a bouncy castle - but you’re on a bike! The saddle and handlebars are really comfy unless I hold it like for a million hours (what I mean is like more than 1 hour or 2 hours and then I need a break).

I really like riding it down steep grassy hills, the tyres get a really good grip. I like to feel in control on my bike, and the Cube bike helped me feel in control. The bike could be a lot lighter because we live on a hill and to get the bike out of the house you need to lift it up stairs. 

I really like having a stand because if I park it then it's really easy to make it stand up, so I don’t have to put the handle bars at the correct angle when I lean it against the wall to stop it falling over. I’ve ridden it quite a lot in the rain and I think it is fine without mudguards.

Cube ANT Helmet

We received the Cube ANT helmet for Rosie to wear while riding the Cube Acid 240 bike. The helmet comes with a built-in light, large vents, insect screens on the vents and a padded ratchet chin closure.

The helmet is quite good when you put it on. It was a bit hard to adjust to the right size at first. It’s quite light, like all the other helmets I’ve worn. The rear light is a good touch but it's quite hard to turn on [you have to really push the middle and the kids found that difficult], it’s a bit tricky to find the bit you push to switch on the light, but it's easier once you’ve learnt it. 

The rear light also seems firmly attached. We’ve lost both the rear lights that came with the Specialized stuff that we have. The Specialized helmet is still Rosie's favourite, as ”I can wear a ponytail at the bottom which I need to do when I ride it to swimming". 

Cube backpack: Pure 6 Rookie

Cube also sent us the Pure 6 Rookie backpack. A 6L backpack designed to enable your child to carry their own tools and snacks on the trail.

When I’m riding it for cycling it's very good, it's the right size so it doesn’t whack my bum when I’m riding my bike. It stays still, which is nice. The zips are totally good and I can open them with my gloves on too.

Overall verdict

Overall the  Cube Acid 240 is a reliable and really good value bike. Great to get disc brakes, and front suspension on a bike at this price point. The components have all worked really well and so whilst weight can be saved by looking for higher-spec components, the ones for this price point on the Cube Acid 240 have done the job perfectly. So we would definitely recommend the Cube for anyone who is looking for a strong and reliable first mountain bike, particularly if you have a heavier child. 

If the weight of the bike is a concern then you may want to look at our guide to the best 24″ kids’ mountain bikes.

Rosie has been a big fan of the Cube and says “it’s the best bike I’ve ever had … It’s very good. If it was the same but lighter then I would give it the best review ever.”

Other articles you may be interested in:

• Best 24″ kids’ mountain bikes ages 7 to 10 years
• Best kids' bike helmets
• Best 24″ kids’ bikes for 7-10 year-olds
• woom kids bikes- a comprehensive guide.
• Buying a kids mountain bike; things you need to know
• The best family bike rides in the Lake District, Cumbria
• Cheaper alternatives to Islabikes
• 12 things you need to know before buying a kids bike