Sitting snugly in the mid-travel category, the Rockrider AM 100 S comes kitted with 150mm of travel up front and 140mm at the rear. It rolls on 29-inch hoops but will happily run 650b wheels if that's your style. The 6061/6013-grade aluminium frame uses a mix of external cable routing and an internally routed dropper cable, which strikes a great balance between ease of maintenance and tidiness.

Hidden neatly underneath the top tube is a Manitou McLeod shock. It comes with a four-position compression adjustment and a rebound dial. The cockpit is fairly modern, comprising a 760mm handlebar and 35mm stem. There's not a lot to complain about apart from the grips.

The Rockrider AM 100 S makes a great bike if you're new to mountain biking. It's well-sorted and can handle pretty much everything thrown its way.

• Read all about its value in our Rockrider AM 100 S review.
• Buy now: Rockrider AM 100 S from Decathlon for £1,499.99

How to choose the best cheap mountain bike

It is important to consider what type of riding you will be doing when looking for any new mountain bike purchase. The basis for any mountain bike is the frame. At this price point, you should be on the lookout for an aluminium frame that has the scope to cater for some choice upgrades when your wallet or your skillset is ready. For the most part, an aluminium frame will be considerably lighter than its steel stablemates but heavier than carbon fibre.

It is highly recommended that you try a new bike out for size. You can always find size details on the manufacturer's website as a place to start, but you should at least have a short test ride at your local bike shop. A poorly fitting bike will not give you the support, confidence or comfort needed to get the most out of your mountain biking experience. 

Are cheap mountain bikes any good?

The myth that cheap bikes are bad is no longer true. The frame designs and the trickle-down of premium features are more prevalent today than ever before. Modern geometry and frame sizing with adjustable suspension forks and even dropper seatposts are everywhere. 

Keep an eye out for a frame that has up-to-date angles (have a look at our bike geometry guide) and can easily be upgraded. Attributes such as dropper-post compatibility with neat routing, ample clearance for wider grippy tyres and possibly even tubeless-ready wheels/tyres. 

What kind of money can I expect to pay for a mountain bike?

As a general rule of thumb, we advise that if you are spending £1,000 or under, you will have more choices and a better-specced mountain bike, most likely a hardtail. That is not to say that you can't get a full-suspension mountain bike - take the Carrera Titan X as an example.

With the amount of development and additional cost of a shock, hardware and moving parts full suspension bikes generally start at the £1,500 mark. Below this point, the frame will be considerably heavier with a compromised specification when compared to a hardtail of the same ilk.

Is it worth looking at second-hand mountain bikes?

Trawling the second-hand market for mountain bikes might be exciting but it does come with added risk - you will lose any warranties and money-back returns policy. It's impossible to tell how the bike was cared for and what type of terrain and conditions it was exposed to during the previous ownership.

If you're unsure about the pre-owned bike, we recommend that you visit an authorised dealer at your local bike shop and buy a new bike. They are a friendly bunch that often have years of experience selling and riding bikes. They will be able to recommend and fit you out on the correct size bike which is the best place to start for the ultimate trail experience. You can talk about budgets and your expected type of use, their feedback will often help your buying decision to ensure you have the right bike for your needs. 

Hardtail vs full suspension - which one should I buy?

For the most part, you will have realised that at the entry-level end of the market the hardtail rules when it comes to value. That's not to say you can't buy a full suspension bike at this price, but the choice will be limited and often have a compromised spec to bring the price down. If you are on a tighter budget, a hardtail mountain bike will give you a better spec. 

The modern hardtail will likely have more up-to-date geometry that will boost your confidence when out on the trail. The biggest names in mountain biking often won't risk their reputation on a budget full suspension bike because of the inherent compromises and low-cost componentry to get the bike under a particular price point. 

As you can see from our list above, there are some brands that can piece together the puzzle of full-suspension mountain bike design for the budget-minded consumer. These performed astonishingly well during our tests with little or no sacrificing the overall performance when out on the trail.  

Will I need to make any upgrades?

As evidenced from the list above of our best-performing cheap mountain bikes, they are often upgrade-ready out of the box. Every mountain biker loves to customise and make upgrades to their steed - the whole industry is based on it to some extent.

Even at the lowest point of the market, bikes will have routing for a dropper seatpost. Wide rims and acres of clearance for some serious rubber. Occasionally some will even spec tubeless-ready rims for when the cheap rubber finally wears down. We will get into tubeless upgrades in more depth later, but the best mountain bike tyres are in contact with the trail and will make some of the biggest differences to a bike's ride characteristics and handling for relatively little dosh. 

The other area that will also tweak your overall experience is the three main rider contact points with the bike. The saddle, the cockpit (bars, stem and grips) and the best mountain bike pedals can make a huge difference to the feel and confidence. 

Before you go spending hundreds of pounds on upgrading your mountain bike you should most definitely consider learning from a coach. We are fortunate to have some of the best and most experienced mountain bike athletes in the world residing in the UK, and many offer coaching so why not book a session to tidy up or improve on the very basic skills needed to make the most out of your mountain bike?  

Should I convert my cheap mountain bike to tubeless?

Upgrading or investing in the best tubeless tyre system is one of the most cost-effective ways to transform your mountain bike and improve its performance on the trail. 

You will need a tubeless-ready tyre, a tubeless valve, a sealed airtight wheel rim and of course sealant to configure a tubeless setup successfully which depending on your bike could prove costly.  We have a whole guide detailing how to convert your bike's tyres to tubeless.

The main benefits of using a tubeless setup are the reduced overall rational mass of the wheels without tubes. They almost solve the problem of punctures from trail side nasties like thorns and sharp rocks and also provide more grip thanks to being able to run lower tyre pressures without the need to worry about pinch flats.

Of course, there are some things that you need to consider with a tubeless system. The sealant can make for a messy tyre change and you should still always carry at least a spare tube just in case. The sealant doesn't last forever and typically will need to be topped up every six months so. Also, it is worth remembering that running tyre pressures too low could leave you vulnerable to damaging your wheels in a heavy impact.