Built for trails and terrain

Hardtails have front suspension only and a rigid rear. They are lighter, simpler, cheaper to own and easier to maintain. For most trail centres in the UK, a good hardtail will do almost everything a full-suspension bike will do, at a fraction of the price. Buy one if you are new to the sport, ride mostly blue and red graded trails, or if you just want the simplest bike possible.

Full-suspension trail bikes have front and rear shocks and typically between 120mm and 150mm of travel. They are the most popular format for experienced UK riders because they cover the widest range of terrain. You can ride them on flat canal paths and down the rockier sections of Welsh and Scottish trail centres. Expect more servicing costs than a hardtail.

Enduro and downhill bikes have more travel, slacker angles, and are designed to go down hills fast. They are overkill for general trail riding and are genuinely slow uphill. Only buy one of these if you know you want to ride technical descents, uplift days, or actual enduro racing. A lot of enduro bikes on the used market have been ridden hard. Inspect carefully.

Wheel size is the other choice worth understanding. 29-inch wheels roll over roots and rocks more easily and carry speed, which is why most modern bikes use them and why they suit beginners and taller riders. 27.5-inch wheels are a little smaller and feel more playful and quick to change direction on tight, twisty trails. Some bikes mix the two, a 29 up front and a 27.5 at the back, to get the roll of the big wheel with the agility of the small one. For most UK trail riding, 29-inch is the confident default.

The single best upgrade on a mountain bike is a dropper post. It is a lever on the bar that drops the saddle out of the way on descents, so you can move around and stay in control, then springs it back up for climbing. Many bikes are dropper-ready even when one is not fitted, so if a used bike does not have one, factor in adding it later. Riders who try a dropper rarely go back, so a bike that already has one is worth a little more.

Under five hundred pounds you are in older hardtail territory. Mechanical disc brakes, basic coil-sprung forks, 2x or 3x drivetrains. Fine for towpaths, fire roads and gentle blue trails. Not built for drops or jumps. A bike at this price with a fresh chain and tyres can still deliver a few seasons of fun.

Five hundred to a thousand pounds gets you a late-model hardtail with hydraulic disc brakes, an air-sprung fork, a 1x drivetrain and proper trail geometry. This is where most first-time trail riders should be looking. You also start to see older full-suspension bikes in this range, but be careful. Worn bearings, tired shocks and stripped threads are common.

Between one and two thousand pounds, full-suspension becomes viable. You will find clean late-model trail bikes from the big brands with 120mm to 140mm of travel. A dropper post, a decent fork, and tyres that still have tread. The best value bikes in this band are often three-year-old full-sus models that have already taken the steepest part of their depreciation.

Two to four thousand pounds is where the serious trail and enduro bikes live. Carbon frames become common, wheel spec improves sharply, and you will see bikes with Fox or RockShox factory-level suspension. At this level always ask when the suspension was last serviced and check the rear shock for oil weep around the seals.

Push down hard on the front end. The fork should compress smoothly and return without clunks. Any grinding or sticking means the seals are past their best, which is a service job. Do the same with the rear shock. Listen for any hiss of escaping air, which is a worse problem and often a rebuild job.

Check the bearings. Grab the cranks and try to push them side to side. Any play is the bottom bracket, the pivot bearings, or both. Lift the rear wheel and spin it. It should spin freely without any rumble. Roughness is a hub bearing issue.

Look at the chainring teeth. Teeth that are sharp and hooked like shark fins mean the drivetrain has done serious miles. A chainring, chain, and cassette is not cheap to replace together. Factor it into the price.

Look under the downtube, especially around the bottom of the seat tube and the chainstays. Mountain bikes pick up rock strikes, and carbon frames can hide damage in these spots. Pay attention to any creases in aluminium frames at the same points.

Specialized, Trek, Giant and Cannondale have the deepest used-market footprint. Parts are easy to find, resale values are predictable, and you can usually identify the model year from the paint scheme. Look out for older Stumpjumpers, Fuels and Anthems in particular. They have aged well.

Santa Cruz, Yeti and Orange have dedicated followings. The bikes are built well and hold their value, but prices can be steep. A Santa Cruz Hightower three years old will often cost more on the used market than a newer Giant Trance of equivalent spec. Whether that is worth it depends on how much the brand matters to you.

Whyte, Vitus, Nukeproof and Ragley are British brands that punch well above their weight. They are usually cheaper to buy new than the big American brands, and that works in your favour when you come to buy used. A two-year-old Nukeproof Mega is one of the best value enduro bikes on the UK market at the moment.

Calibre bikes, sold through Go Outdoors, are a common entry point for new riders. The Bossnut and the Line models offered remarkable value new, and they are plentiful on the used market. Frames are steel or aluminium, parts are standard, and they are worth a look if you are after your first proper trail bike.

Mountain bikes cost more to keep running than road bikes. Suspension needs servicing. Brake pads and rotors wear faster. Tyres cost more. Budget at least a hundred pounds a year in consumables if you ride every weekend, and more if you ride hard or in wet and muddy conditions.

Winter in the UK is brutal on mountain bikes. Grit, mud and salt will eat bottom brackets, pivot bearings, and chains. Washing the bike after every muddy ride is not optional if you want it to last. If the previous owner obviously did not do this, expect hidden wear.

Cyclesite runs every mountain bike through the UK stolen-bike databases before it goes live. Given that mountain bikes are a popular target for thieves, it is worth checking the frame number yourself as a second step. Ask to see the original receipt, service records, or any photos the seller has from when they bought the bike.