Several sizes available:
S: between 1.50m and 1.64m
M: between 1.65m and 1.74m
L: between 1.75m and 1.84m
XL: between 1.85 m and 2.00 m

If you are on the limit between 2 sizes:
Choose the smaller size for easier steering (easier to handle) and comfort (straighter back).
Choose the larger size for easier pedalling with a more stretched-out position (position more suited to performance).

Men's or women's mountain bike?
This Rockrider ST 520 mountain bike is unisex.

For greater comfort, the women on our mountain bike team recommend replacing the saddle with the Women's 500 Sport saddle, which is adapted to women's bodies.
A range of Rockrider mountain bikes specifically designed to fit female morphology is also available (specialised saddle, stem, fork and brake grips).

This ST 520 mountain bike has been entirely designed and developed at the B'Twin Village in France (Lille). We've designed, developed and tested the ST 520 MTB for comfort and efficiency. This combines to give MTBers confidence to overcome any new obstacle.
We have involved real MTBers at every stage of this bike's design process.
And we hope that the Rockrider ST 520 is everything you could hope for to give you excellent MTB rides.

For a lighter weight and more efficient pedalling, the Rockrider ST 520 frame has been designed with 6061 aluminium (only 1.9 kg in size M). Our designers have designed and developed it so it is comfortable and easy to manoeuvre. Its slope has been designed to keep your back straighter. The lower bottom bracket helps keep you more stable during turns.

Directly adjust the stiffness of the suspension to your weight, to more easily travel over roots and stones.

The 80 mm front suspension is designed for slightly uneven trails and helps you overcome your obstacles with no worries. It is based on a mechanical spring and is reliable. And it's easy to look after.

This mountain bike has no rear suspension. This is a "semi-rigid" mountain bike.
Compared to a full suspension mountain bike (with rear suspension), the advantages are clear: lighter weight, you will spend less energy on flat ground. However, if you want more comfort, the ST 520 MTB also exists in a "full suspension" version with a rear shock absorber.

3 8-speed chainwheels, or a wide range of 24 speeds.
2 quick shifters on the handlebar.
Left (chainwheels): control ascents/descents.
Right (speeds): more precise control over your pedalling.

In detail:

- Triple chainwheels: 22, 32 and 42 teeth
- Shimano Altus or Microshift FD-M22 front derailleur
- SRAM X3 rear derailleur
- SRAM X4 shifters, with speed indicators
- SRAM PG820 8-cog cassette, 11 to 32 teeth

With its adjustable stem, the ST 520 controls are close at hand. The all-aluminium B'Twin stem is 70 mm (size S), 80 mm (size M/L), or 90 mm (size XL) and can be raised using 5 adjustment intervals: + 0mm, + 7.5mm, + 15mm, + 22.5mm, + 30mm.

In detail:

- 680mm oversized aluminium handlebars
- Soft touch B'Twin sport grips for good grip and a comfortable feel.

Our teams conceived and designed an exclusive saddle for this bike. Suitable for different hip sizes, its "hammock" shape is particularly good for sport touring. The Flex 27.2mm diameter aluminium seatpost also contributes to its increased level of comfort.

Quick and easy tool-free adjustment of your saddle height using the adjustment lever on the seat post clamp.

The HAYES M-X5 mechanical double disc brakes give you gradual, powerful braking at the front and back. Whilst the aluminium Tektro brake levers are light, precise, and easy to hold. Just two fingers are all you need to brake.
Try to get your brakes adjusted at least once a year.

Take on obstacles! The aluminium wheels are effective and sturdy: 27.5" double-walled rims. Their diameter is the perfect balance between comfort and performance. With their 28 spokes, they are lightweight, stiff, and durable.The exclusive 27.5" x 2.0 B'TWIN ALL TERRAIN DRY tyres are designed for dry terrain. Their side lugs provide good traction during turns. The recommended tyre pressure according to the weight of the rider is marked on the tyre sidewall.

The ST 520 is supplied with platform MTB pedals mounted on bearings, made from resin for light weight and safety. If your foot slides on the pedal, there's less risk of injury.

Not all rides start on your doorstep. This is why we've made it easy to remove and attach the front and rear wheels. They are equipped with a quick-release system.
A bike carrier will make your life easier if you want to avoid dirtying your car.

Your ST 520 mountain bike is supplied with a bell, lights, wheel reflectors and pedals.

The frame is compatible with:
- front and rear mudguards,
- stand,
- bottle cage,
- saddle bag,
- rear pannier rack,
- child seat (add an additional pannier rack for sizes S and M to avoid touching the rear wheel)
etc.

Tip No.1
When mountain biking, there is always the risk of a fall: don't forget to wear a helmet.

Tip No.2
Even if the saddle is comfortable, cycling shorts with a pad (saddle-shaped foam) are a real plus for preventing glute pain.

Tip No.3
If you don't want to stop to drink, bring water in a bottle or water bladder to access it while riding.

Tip No.4
Punctures are always possible, remember to bring a repair kit.