How to choose your mountain bike?

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  1. Frame materials
  2. Suspension
  3. Brakes
  4. Gears
  5. Wheel and tyres
  6. Pedals
  7. Mountain bike types
  8. Mountain bike sizing
  9. Mountain bike accessories

With fat, grippy tyres, powerful brakes and wide-range gears, mountain bikes are the 4x4s of cycling, taking you away from the traffic and noise along forest roads and trails and deep into the countryside. Improvements in suspension, disc brakes and gears mean today’s mountain bikes are easier and more fun to ride than ever. Our range of mountain bikes will put a smile on your face whether you’re pootling along a towpath or flying down a mountain.

Mountain bikes cost from around £100 to many thousands. As you go up the price range they get lighter and more reliable and perform better. That means brakes get more powerful, gears have a wider range to make climbing hills easier, and suspension systems get better at absorbing the bumps. But there’s no need to spend a fortune to get a bike that’s capable and fun on the trails. Let’s have a look at N bikes from the Decathlon range to see what you get for your money.

For just £240 the B’Twin Rockrider 520 offers a great entry point to real off road riding with fast-rolling 27.5-inch wheels, wide-range 24-speed gears and powerful disc brakes, all hung on a lightweight aluminium frame. The B’Twin Rockrider 520 also has a suspension fork to soak up the bumps and make riding easier on your hands. It comes in four sizes so you can get a perfect fit and components such as the stem and handlebar change in size with the size of the bike for even better customisation to the rider. Less expensive mountain bikes are best suited to easy trails in parks and along towpaths, but the Rockrider 520 is equipped to take you anywhere your skill and bravery can handle. The B’Twin Rockrider 540 is ready to go straight out of the box too, with a handy accessory pack comprising water bottle, bottle cage, pump, saddle bag, a spare inner tube and three tyre levers.
BTwin Rockrider 540
For £380 the B’Twin Rockrider 520S is a great-value full-suspension bike, with shock absorbers front and rear. It has the same wide-range gearing as the Rockrider 540 with lightweight air suspension to soak up rear wheel bumps. Hydraulic disc brakes slow you down however quickly the suspension tempts you to go.
With B’Twin’s new lightweight aluminium frame, the £750 Rafal 700 is a fast front-suspension mountain bike that’s as happy blasting round the woods as it is storming away from your rivals on a race course. To keep things simple it has a 2 x 10 gear system for fast, reliable shifting, and Shimano’s rattle-resistant Shadow rear derailleur, along with top-brand Mavic wheels and Hutchinson tyres. Most importantly, at just 12kg, it’s substantially lighter than cheaper mountain bikes. That weight reduction makes it easier to flick around on the trails, and easier to get up hills.

At £1,000 nad £900 respectively, the B’Twin range is topped by a pair of top-flight bikes, the Rockrider 740S full suspension bike and the Rafal 720 Limited Edition hardtail. The Rafal 720 Limited Edition is a pro-quality hardtail that’s fully-loaded with top-end equipment including Shimano’s superb Deore XT gears, brakes and wheels and Hutchinson’s ultra-versatile all-conditions Taipan tyres. With the same frame and handling as the Rafal 700, the Rafal 720 Limited Edition is a light (just 11.5kg), versatile bike for riders who want to go fast. If your ambition runs to coming downhill fast as well, then the Rockrider 740S is for you. With 120mm of suspension travel front and rear it eats rocks and bumps, and its suspension design makes sure all your pedalling effort goes to the wheel with no energy-robbing ‘bobbing’.
So, what have we learned? Mountain bikes get lighter and more capable as you go up in price, and in this price range they get better rapidly. You could spend twice as much as a Rafal 720 Limited Edition or a Rockrider 740S costs and not get a bike that’s twice as good; diminishing returns set in. Allow some money in your budget for accessories and clothing. You’ll need at least a helmet and gloves and there are some other accessories that are very handy to have; see ‘Accessories’ below.
First, let’s take a closer look at the features of mountain bikes.

1Frame materials

Most mountain bikes are made from aluminium alloy, which is relatively easy for manufacturers to build into light, stiff frames and especially good for the complex shapes needed for mountain bikes with rear suspension.
Entry-level mountain bikes have steel frames. Steel is inexpensive and tough so makes for durable bikes that don’t cost the earth, but it’s heavier than aluminium.
btwin steel frame black

2Suspension

Suspension improves the ability of a mountain bike’s tyres to grip the terrain, and makes the ride more comfortable. Basic mountain bikes rely on just the cushion of the tyres for suspension, and are best suited to fairly smooth trails and tracks.
A bike with a suspension fork has better handing and is more comfortable than one with a rigid fork, making it work better on rough tracks. With a rigid frame, these bikes are known as ‘hardtails’.
The ultimate in comfort and handling is a bike with suspension on both wheels. Rear suspension allows you stay seated on rough trails, which helps keep the bike planted.
btwin suspension

3Brakes

Mountain bikes have either disc brakes or V-brakes.
Disc brakes have a mechanism at the end of the fork or rear stays that presses the brake pads against a disc on the wheel hub. Because the braking surface is well away from the tyre, disc brakes are less affected by wet conditions and provide powerful, reliable braking with excellent modulation (fine control of braking power).
Disc brakes can be actuated by either cables or hydraulic hoses between the levers and brake mechanism. Hydraulic brakes are more powerful, but more expensive.
V-brakes have arms that push brake pads against the rim. They stop well, but are more affected by the wet than disc brakes, and rely on the rim being straight; if it gets damaged they can become snatchy.
btwin disc brakes

4Gears

Mountain bikes have wide-range gears that equip you for both zooming down dirt roads and climbing the steepest trails. General-purpose mountain bikes usually combine three chainrings on the pedals with between seven and ten sprockets on the rear wheel.
More performance-orientated bike have two chainrings; you lose some high gears, but gain simplicity and reliability.

5Wheel and tyres

Mountain bikes usually have 26-inch wheels, which make for versatile, responsive bikes that turn and accelerate easily.
In the last few years two new sizes, 27.5-inch and 29-inch have emerged. Both offer faster rolling on rough surfaces because the bigger wheel effectively ‘flattens’ the dips and bumps. However, the extra weight of the larger 29-inch size means it’s harder to get rolling so many manufacturers have settled on 27.5-inch as the optimum size for performance mountain bikes.
Wide, knobbly tyres for gripping rough, loose and muddy surfaces are the distinguishing feature of mountain bikes.
Most mountain bike tyres are about two inches wide, which makes for a good combination of grip and cushioning. Some bikes will take even wider tyres and ‘fat bikes’ — designed for riding on snow and ice — have tyres over four inches wide.
btwin wheel and tyres

6Pedals

Most off-the-peg mountain bikes come with ‘flat’ or ‘platform’ pedals. As the name suggests these have a flat area for your feet and are broad so they’re comfortable with soft-soled shoes. Better flat pedals have steel studs that dig in and grip the rubber of your shoes, providing some security, but still allowing you to quickly get off the pedals.
The alternative is pedals with a mechanism that grips a special stud, or cleat, on the sole of the shoe. These are known as ‘step-in’ or ‘SPD-style’ pedals, after the Shimano SPD pedal system, the first mountain bike pedal of this type.
SPD-style pedals provide a firm connection to your shoes; you press down to engage and are then attached to the pedals until you twist to release. The effort needed to release from the pedals is usually adjustable.
SPD pedals need special shoes with a recess and attachment points for the cleats. These shoes have stiff soles for efficient power transmission.
B'twin pedals

7Mountain bike types

There are many different variants on the basic idea of a flat-handlebar fat tyre bike, intended for different styles of riding or, in some cases, racing. Some serve very small niches, others can be used in a wide range of tracks and trails. Let’s take a look at a few.
Cross-country bike: Low-slung, light and fast these are bikes intended for mass-start racing. In the hands of skilled riders they’re very capable on a wide variety of trails. Cross-country bikes are usually hardtails or very sophisticated full suspension bikes.
Trail bike: The most popular category in the UK, these are bikes that will handle almost any trail — hence the name. Trail bikes usually have both front and rear suspension with four to six inches of travel, though some riders favour the hardtail equivalent, often called a ‘hardcore hardtail’. Trail bikes are light enough to ride uphill, but tough and capable enough for all but the very steepest and roughest descents.
Enduro bike: the other side of very blurred line from trail bikes, enduro bikes usually have a bit more travel and handling more orientated toward descending, though they still climb well. They’re intended for the burgeoning racing format of enduro, where riders are times on technical downhill sections but have to ride between them within a fixed time.
Downhill bike: Full suspension bikes with up to ten inches of travel, these are bikes designed to descend as quickly as possible on very steep and extremely technical race courses.

8Mountain bike sizing

Mountain bikes are sized like t-shirts: small, medium, large and so on. Our size guide will help you choose, but if you’re in doubt, it’s best to visit a store and try the bike you’re considering.
You should have 3-4 inches (7-10cm) of clearance when you stand over the bike with your feet flat on the floor. You’ll often find yourself jumping off the saddle and if the front wheel is raised at the time, then you need some margin of error.
You should be able to comfortably reach the handlebar while sitting in the saddle, with a semi-upright riding position. This allows you to move around on the bike and out of the saddle, which you do a lot while riding off road.

9Mountain bike accessories

You’ll often find yourself out of mobile phone range when riding in the hills, so it’s important to be self-reliant. That means carrying a minimum set of accessories to fix mechanical problems and look after yourself.
btwin helmetHelmet: Minor spills are a mountain biking fact of life. A helmet provides some protection against minor head injuries and is great for bouncing low branches off your head. It won’t save your life if you’re hit by a truck, but it might save you a trip to A&E to have a messy scalp wound stitched.
Gloves: What do you do when you fall? Put your hands out to try and stop yourself. Without gloves, you can end up painfully picking gravel out of your palms, leaving your fingers cut and sore for days. Mountain bike gloves usually cover the whole hand, though traditional fingerless cycling gloves are great for warm days.
Tools & spares: A multi-tool with bits that fit all your bike’s nuts and bolts is a must, and should include a chain tool so you can fix a broken chain. That’s a rare problem, but one that’s very hard to bodge or limo home from.
You should also have a spare tube, tyre levers and a pump.
Water: A bottle and cage or two on your bike can carry enough water for short to medium rides. If your planning long days in the woods, then a water-carrying backpack, known as a hydration pack, can carry up to three litres and also gives you somewhere to carry your tools and spares and useful things like a jacket, wallet and so on.

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