For the love of bikes!

Common mountain bike tech jargon explained

From gusset to gnar, mountain biking is strewn with jargon that’s hard for newbies to understand. Technical phrases can be particularly confusing as mountain bikes can be pretty complex machines these days.

If you find yourself confused by MTB-babble, fear not as we’ve handily explained some of the common terms you’ll come across when reading bike reviews or product pages…

Boost

Invented by SRAM, Boost is a the latest standard in wheel hubs that is slightly wider than standard hubs. Boost hubs are 110mm at the front and 148mm at the rear.

The extra width Boost hubs provide improves wheel stiffness and durability, makes your bike’s handling feel more precise, gives more clearance for bigger tyres and provides a wider range of chainring options.

Boost is incompatible with standard sized components and frames though, as you’ll need specific Boost width forks and/or chainstays to use Boost hub-ed wheels.

 

Butted tubing

You’ll usually find the term butted popping up when metal bike frames are being described. It refers to the tubes used in the frame that have thicker walls at one end than the centre (single butted), at both ends (double butted), or three different wall thicknesses (triple butted).

More expensive bikes will have triple or custom butted tubing and are usually lighter and stronger as a result.

 

Drivetrain

Drivetrain is a catch-all for bike’s crankset, cassette and derailleur/s. You’ll find that drivetrains are referred to in one of two ways. 11-speed or 12-speed refers to modern drivetrains that have a single ring on the crankset and 11 or 12 cogs on a wide-ranging rear cassette.

The other way you’ll see drivetrains indicated is as 1×11, or 2×10, etc. The first number refers to the number of front rings attached to the crankset and the second indicates the number of cogs on the cassette. So a 1×11 drivetrain has 11 gears and a 2×10 has 20.

Less is more with drivetrains these days, as even though modern 1x gearing has less gears than older 2x or 3x systems, the total gear range is just as wide, though with less gears available, the gaps between the gears is bigger.

 

Dropper post

This a seatpost that lets you adjust your saddle height as you ride – usually via a bar mounted lever.

Dropping your saddle for descents allows you to get into a much better body position than you would be able to otherwise. A dropper post also allows you to easily adjust your saddle into the optimum position for climbs.

 

Dropout

The point where the wheel enters and attaches to a frame or fork. With several different axle standards (QR, 15mm through-axle, etc) dropouts vary from bike to bike.

 

Frame geometry

The angles (and lengths) of a bike frame. Modern trail bikes tend to have slacker angles than they did a few years ago and many bikes have got longer too – this is also called progressive geometry.

 

Full suspension bike

A mountain bike with shock absorbers that absorb impacts to the front and rear wheels. Most commonly, the bike will have a suspension fork and a swing arm with a shock absorber to the rear. Also known as a full-sus bike or, less commonly these days, dual suspension.

 

Hardtail

A mountain bike with a rigid frame and front suspension fork. Typically, hardtails are lighter and less complex than full suspension bikes.

 

Head angle

The angle of a frame’s head tube. This also determines the angle of the front fork. A mountain bike with a head angle of 66 degrees or less is regarded as slack, while one with a head angle of 67 degrees or more would be steep.

 

Linear travel

Usually used when talking about mountain bike suspension, linear refers to the level of resistance of a shock or fork as it compresses. Linear suspension means that the shock or fork will have fairly consistent rate of resistance throughout its compression.

 

Plus-sized

Refers to wider rimmed wheels (and bikes), usually 40mm, fitted with high volume tyres, usually 3in wide or so. Usually plus-sized wheels are 27.5in (27.5+), but 29+ and 26+ versions are also available.

 

Progressive travel

Like linear, the term progressive travel refers to MTB suspension. Shocks and forks with progressive travel have more compression resistance to begin with, then less resistance once compression increases.

 

Rebound

The return phase of a suspension fork or shock to full length after it has absorbed an impact.

 

Reach

The distance between the centre of the head tube and a point taken vertically from the centre of the bottom bracket. It’s a good measurement of how long a bike will feel when standing on the pedals.

 

Seat tube angle

The angle of a frame’s seat tube. In a conventional frame, the seat tube runs from the bottom bracket to the seat post. On most modern bikes the seat tube angle is around 73 degrees.

 

Through-axle

Through-axles have replaced old style QR wheel skewers. Instead of a thin, tensioned bar, through-axles are 15mm or 20mm thick on the front wheel and 12mm to the rear. These tubular axles provide a much stiffer mount for your wheels and they also stiffen your frame and fork.

 

Tubeless

Tubeless tyres do away with puncture prone inner tubes and instead have a Latex-based solution that rapidly plugs any small holes.

While they can be frustrating to initially set up, it’s well worth any extra hassle for the amount of punctures you avoid.

 

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