Jargon busting the latest MTB standards

In the market for a new bike? Here’s how to navigate the minefield of modern standards.
Aaron Gwin's 2016 MTB World Championships YT Industries Tues bike with custom USA themed paint
Side on for all the splendor © Bartek Woliński
By Ric McLaughlin

The bicycle is a simple machine, right? Well, in theory yes, but these days there's a bit more to man's most noble invention. Mountain biking has always been a fan of new technologies. Some have caught on and stayed while others have failed and disappeared only ever to resurface in post-ride bar room 'Do you remember...' conversations.

The only thing that every single one of these fads will have had in common is a supposedly catchy buzzword or acronym, designed to stick them, Velcro-like, into the minds of consumers.

If you're in the market for a new mountain bike, congratulations. There aren't many better problems to have than umpteen open browser windows and an internal debate raging as to which machine best suits you. Whilst the bikes on sale now, both online and on dealers floors, are the best ever, the level of 'standards' (all those buzzwords and acronyms in the specification panels) is also at an all-time high.

Here's what they all mean...

Metric shocks

What this means: More options for frame builders equals better shock internals

This is perhaps of more relevance to bike designers than to punters, but it's a term we’re seeing used more and more in new bike literature. Designers were previously tied to imperial measurements when it came to shock lengths, but now the industry's biggest brands have introduced metric size shocks.

Ultimately, the choice is still that of the person behind the CAD package, but it potentially eliminates the need for awkward mounting fitments, which frees up more room inside shocks and equals better internals – which equals more fun.

That's not to say that you should disregard bikes with imperially measured shocks; this is likely to be a slower burn industry trend.

Boost axles

Fox Racing Shox Kabolt 15mm front axle on Julien Abalone's BMC XCO bike
Fox Racing Shox Kabolt 15mm front axle © Bartek Wolinski/Red Bull Content Pool

What this means: Slightly wider axles making for stronger wheels

10mm mightn't sound like a lot, but trust us, it matters. Boost is the term given to the industry's latest axle standard and relates to how wide a bike's hubs are. For many years, bolt-thru front axles were 100mm wide, Boost pushes them to 110mm. Rear wheels meanwhile have grown in width from 142mm to 148mm. This is no problem if your new bike comes fully equipped with Boost, but if you're upgrading a fork or wheelset then you need to be careful that you order everything to match.

The idea behind Boost is that wider hubs benefit from a better bracing angle for the spokes, which can result in a stronger and stiffer wheel. In terms of the rear wheel, it also allows frame designers to shorten chainstays, thanks to increased tyre clearance, making for a more nimble bike.

Some wheel manufacturers have been helpful enough to produce adaptor kits to convert non-Boost wheels so don't despair if you're considering a new build.

35mm bars

The Renthal carbon fibre Fatbar on Aaron Gwin's Worlds YT Mob Tues
View of the Renthal 35mm Fatbar and stem © Bartek Woliński

What this means: Handlebars that are a bit thicker in the middle

It's been a slow incubation period for the 35mm handlebar, but finally they look poised to take over. It may be tempting to think that a handlebar is just a section of metal tubing, but there's a lot more to them than that. How they deal with vibration and trail chatter can greatly change your ride experience. Key to this is how wide the diameter of a handlebar is at the point where the stem clamps on. That's where this new standard comes in.

For the last three or four years there's been a drip feed of companies launching 35mm thick bars (the previous norm being 31.8mm), but now more brands are starting to spec them as standard equipment so after market manufacturers are duly producing replacement/upgrade parts to tempt buyers.

Of course, if the clamping surface of your bars is 35mm then you'll require a corresponding 35mm stem, which does add to the cost of any upgrades you're considering.

Wide rims

The ENVE Composites M90-Ten rims on Josh Bryceland's Worlds Santa Cruz V10
ENVE Composites M90-Ten rims are pure carbon gold

What this means: More room inside tyres makes for more grip (supposedly)

Arguing about wheelsize and wheel standards in MTB is a bit like throwing a metal bucket down a well and then trying to make sense of the clangs and bangs it makes on the way down. Recently though, manufacturers started to think that perhaps there weren't enough arguments about wheels and decided to start fiddling with their width too.

Altering the internal rim width of a rim equals a wider mounting place for your tyre, which means a larger volume and an increased footprint. Can you hear those clangs and rattles? Well, that's the complex argument involving various variables such as tyre choice, tyre pressure and weight.

There is a lot of science behind this and there are a lot of interesting arguments online. How does it affect your choice on buying a new bike? Well, it's a trend the industry seems to be taking seriously and therefore we predict an increase in tyres produced specifically to work well with wider rims. A bike which comes with them as standard should be good to take advantage of them.

Loïc Bruni rides his bike during testing in New Zealandin 2017
Loïc Bruni tests a set-up in Queenstown © Miles Holden

So there you have it, there are even more standards to take into consideration than ever before. Do they each represent a little step forward in terms of performance or do they only serve to make buying your next bike all the trickier? Whatever your views on standards, one thing is certain; there will be more to come.

It's important to remember that not every bike needs every standard but how long you intend to hold on to it and any future upgrades you might fancy making need to be considered before you take the plunge.

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