What exactly is a Plus bike and what is it meant to be good for?

You’ve probably seen the phrase ‘Plus bike’ being used a lot of late. Here’s a simple breakdown of what Plus bikes are why they’ve been invented.

What is Plus?

Basically, Plus means bikes that have tyres that are 2.8-3.0in in width.

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The rim diameters of Plus wheels are 27.5 or 29in, just like regular non-Plus wheels. But the widths of the rims are significantly wider – often around 40-50mm internal width.

The extra width rims are needed to better support and give proper shape to the oversize tyre carcass.

Usually, but not always, bikes running Plus tyres have the Boost hub standard.

Plus is not the same thing Boost. Two different things. Plus is about tyres and rims. Boost is about hubs.

Not all Boost hubbed bikes are Plus bikes (some Boost hubbed 29ers just have Boost to increase regular wheel stiffness).

Not all Plus bikes have Boost hubs but the vast majority do.

>>> How to convert your 29er to a plus bike

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Why?

Plus bikes are ‘diet Fat bikes’. Fatter tyres and wider rims that sit between regular tyres/rims and Fat bike tyres/rims.

Fat bikes are quirky bikes with huge balloon-like 4.0in+ tyres. They’ve become something of a cult, especially in America.

You could say that Plus bikes have been inspired by the bike world’s experience of Fat bikes. Much in the same way that 27.5 bikes came about by the industry’s experience with 29ers.

The idea is to get some of the advantages of Fat bikes whilst avoiding most of their disadvantages.

>>> Complete guide to wheelsizes: 26in, 650b, 650b+, 29in, 29in+

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Speaking of advantages and disadvantages…

Pros

Massive increase in traction on all terrain other than slick mud. Plus tyres’ much larger contact patch offers addictive levels of grip.

Still quick-rolling. Increased contact patch means tyres can have shallower tread and still be mega grippy yet not draggy.

Increased comfort.

More forgiving of line choice and rider error.

Unleashes much more potential in hardtails especially.

>>> Scott Genius 700 Tuned Plus (2016) review

Cons

Fine-tuned air pressure is everything. A couple of psi here or there can radically alter the handling.

Flimsy and delicate tyres. To keep weight down, current Plus tyres have thin sidewalls which can result in squirmy handling and rock-ripped tyres.

Plus tyres can struggle to dig into slick mud or very loose dry terrain so can feel a bit surfy and vague.

Some Plus tyres are noticeably heavier than regular tyres and as such can take a bit more effort to get up to initially speed from a standstill.

Should you get a Plus bike?

If you’re in the market for a hardtail then you really should try to have a go a Plus tyres hardtail. Immense grip and overall speed increases can be had.

If you’re a beginner rider then Plus bikes have some serious good points. Essentially they are more forgiving, more comfortable and safer. Plus offers a lot of benefits found on full suspension bikes at a much lower cost and complexity.

Experienced riders used to full suspension trail bikes are more of a complicated proposition for Plus bikes. The extra traction is good. So is the forgiving nature of fat tyres. But the fragile and unsupportive tyre sidewalls can be frustrating. The vague handling in mud can also be an issue for some. Try before you buy. Or wait to see how the Plus scene develops.


Video: What is Boost?


What does the future hold for Plus?

It’s relatively early days still so it’s hard to say. They’re not going to disappear but perhaps where they fit into the MTB market is still a bit up in the air. They aren’t just for beginners.

Perhaps the key issue is tyre construction. Even the staunchest traditional diehard riders who have ridden Plus bikes have admitted they are a blast to ride. But they’ve also been plagued with torn tyres and pinch flats due to lightweight tyres.

Adding meat to the tyres will help prevent this but adding rotating weight to a bike is generally regarded as something of a no-no as it reduces acceleration.