Winter Re-Wind: The Plus Size ‘Revolution’

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Chipps and the not-very-accurate Singletrack History Department explore just what has been going on with wheel and tyres sizes recently.

This article originally appeared in Issue 98 of Singletrack Magazine. Subscribers have full access to all current and previous Singletrack content as part of their subscription.

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Words by Chipps, photos by Chipps and Mark.

It seems that the mountain bikers of the UK have only just come to the realisation that the 26in wheel has fallen out of favour with the bike industry. Meanwhile, in the pursuit of progress, whatever that is, wheels have got bigger. And now they’re getting wider too.

The first sign of wheel evolution from the standard paperboy bike’s 26in wheel was the 29er. First appearing around 2001/2002, it took several years before big wheels were taken seriously in the UK. My own theory about this is that there were several reasons to hinder its acceptance. Firstly, the early adopters were mostly singlespeeders on Surlys and On-Ones, which meant that the rest of the mountain bike world viewed those 29in singlespeeds as just an added disability in that ‘Look, I’m making things harder for myself’ way that singlespeeders (and I speak from years of experience as one) love showing off about. Secondly, the only 29in tyres you could get in the early 2000s were, for want of a better description, ‘California summer tyres’ that possessed little traction on the muddy British trails. And thirdly, the lack of 700c mountain bike wheels and rims put riders back into the early mountain bike days of having to borrow components from touring bikes.

The Plus Size Revolution
Chunky tyres are what we’re here for, but just how chunky are you willing to go?


The 27.5in thing happened quicker. Although Kirk Pacenti had been championing this mid-size for several years, it was only really custom frame builders that had the luxury of making frames to fit these in-between sizes. And this is where I come in with one of my theories again…

The Plus Size Revolution
Does Plus give us that extra grip we all crave?


A disturbance in the force.

In the USA, where the majority of bike industry decisions are seeded (even though they may play out eventually in Taiwan), the mountain bike world had gone 29in for hardtails and for shorter travel full suspension bikes. The Americans have never really got the idea of the hardcore hardtail, due to never wearing their full suspension bikes out every winter. However, when these riders went to buy a bike for bigger roots, rocks and drops, they had a problem. The American bike shop could point them at long, rather heavy and unwieldy 29in trail bikes, or to the perfectly capable long travel 26in bikes. ‘Ahh, but I KNOW that big wheels roll better, why would I go for that older, smaller size?’ they would ask.

And so bikes started appearing with bigger (but not the biggest) 27.5in wheels, that worked just like the older 26in bikes, but rolled better. Even if it was just an ‘nth’ better, they were better. Downhill racers, never ones to turn down an almost imperceptible performance advantage, also started moving across to 27.5in wheels.

The Plus Size Revolution
Pretty sure Mark could have done that on a shopping bike with no tyres or tubes.

So now we have 26in bikes, still beloved in the UK, and for gravity riders who like the stronger wheels and snappier acceleration; 27.5in wheels that roll a teeny bit better than 26in, still give a playful ride and allow for more compact suspension bikes than… 29in wheels, which are adopted en masse by cross country racers and the longer-legged map-crossing riders. We’re finally happy. Oh, but don’t forget the fat bikes. The only new 26in tyres designed in the last five years have been for this new niche – that’s actually already a decade old. The fat bike started to creep from its winter home; firstly (and arguably back) to the desert sands and then to the mountains, where riders started using their fat bikes for trail riding and exploring off the beaten path, where the big wheels roll over anything.

So, now we have all the wheels we need, right…?

The Plus Size Revolution
Is Plus going to be the happy medium between floaty fats and ‘regular’ tyres?

Feeling some kramp.

Nope. A couple of years ago, Surly introduced the Krampus – a hardtail with 29in wheels, but three-inch tyres. There was initially only one tyre tread available: Surly’s Knard, which (just like the early 29in tyres) was a US-summer tread that turned into a slick when shown British mud. Nevertheless, riders liked the confidence and the hoon-a-bility of this new size in the dry. Who cares that you need a whole new bike to experience it? (Oh, OK, quite a few of you…)

Some bike companies started looking at this new tyre size. Could it be the next big thing? Drawings were drawn up, frames were tweaked to take the biggest 29in tyres then available, on rims wider than normal. And rims got bigger too, as riders discovered that more rim width allows the same tyre to run with lower pressures and often a better-supported shape. 29+ seemed to be happening.

The Plus Size Revolution
Braapp and Gnarrr

Meanwhile, in 2014, Trek showed the world a new open ‘standard’ called Boost. This involved widening the distance between hub flanges to create a stiffer wheel. While Cannondale had achieved a similar result with its F-Si race bike, offsetting the whole back end of the bike by 6mm in order to allow more front mech clearance and an un-dished rear wheel, this new Boost made the rear hub 6mm wider (and the front hub, 10mm). The chainrings were also shifted outboard by 3mm too. This needed new frames, cranks and wheels that worked with each other.

Trek justified Boost by saying that it made for stiffer 29in wheels, though some people couldn’t help but notice that it conveniently also allowed room for much bigger tyres to clear the chainset (the brand was already working on a prototype of the new 29+ Stache at the time). With 1×11 drivetrains becoming affordable, the frame designers could now justify ditching the whole front mech (even though Shimano had just spent the previous couple of years designing a super-compact front mech that was driven from the front, rather than above or below…).

The Plus Size Revolution
It’s true that new bikes are better than old, but how many wheel size are you willing to go through?

Goldilocks plus.

But – as you’ve guessed – 29+ isn’t where this story ends. One rim manufacturer I know went off to the Taichung Bike Week in late 2014, with its 29+ rim design all done and ready to make, only to be told, ‘Forget it completely. Didn’t you hear? It’s all about 27.5+ now!’…

Where had this 27.5+ movement come from? A single tyre and rim combo in this size existed at that time: WTB’s 50mm Scraper rim and 2.8in Trailblazer tyre. Together they weren’t quite ‘plus’, but they were big enough to get an idea of the ride of bigger sizes – and they’d also fit into most 29in frames without modification.

The Plus Size Revolution
Looks like a mountain bike to us

The first the world knew about them was when Rocky Mountain showed a prototype off-road touring bike called the Sherpa at the 2014 Sea Otter. As for the rest of the batch of Scraper rims and Trailblazer tyres that WTB made, it seemed that the whole first production run of this combo never made it to bike shops. They were all snapped up by bike company product managers, not wanting to miss out on a trend and eager to wedge them into a 29in frame while they worked on their own ‘plus’ frames that would take the looming tsunami of 3in tyres and even wider rims.

And that kind of brings us up to date. Several companies have recently launched ‘plus’ bikes and, come Eurobike in August, you won’t be able to move for the things as bike companies scrabble not to be left behind.

The Plus Size Revolution
More air volume means better comfort when you’re fully rigid

Why bother?

So what are the advantages of 27.5+? Some companies and riders cite better rollover and much better traction than ‘skinny’ 2.3in tyres. You can run them at 12psi and get fat bike-like traction, without the tyres weighing a kilo each; they’re easier to set up tubeless and they need less effort to spin up to speed than fat bikes, yet they give you a similar amount of flotation to smooth out the trail.

Equally importantly, though, they make your bike look like a cartoon bike. You can see why Specialized sees the wheel size as being encouraging to beginners; bikes with it look safe and capable of shrugging off trail obstacles. Plus-size wheels bring some element of fun to the ride and, as Gary Fisher famously said: “If you want to go fast all the time, get a road bike and race round and round. If you want fun, get a fat bike.”

The Plus Size Revolution
Big tyres, and suspension? Is this finally a true do it all machine?

But not everyone is so keen. A pro enduro racer said to me: “Now that bikes and suspension have gotten so capable, I’ve become really keen on having the most quiet, stable, smooth, hooked-up feeling bike I can muster. Uncontrolled pneumatic rebound isn’t part of that set-up for me.” And a soft, 3in tyre adds a lot of squish, slide and unpredictability to a bike that is sometimes aimed with inch-perfect accuracy at high speeds. Many smaller manufacturers aren’t keen either, especially since they’re being badgered to make everything in carbon these days. A move to the Boost back end needs complete retooling of every frame size they make. Wheel makers have to have new hub forgings made. All of this will cost money that will eventually show up in retail prices. And, as one wag put it: “Why are we playing with wheel sizes when tyres still go flat and we still have exposed derailleur transmission systems? Fix those first!”

Those chubby tyres do add a feeling of security (and yes, fun) to a ride, in the way that fat carving skis are welcoming to the newcomer and flattering to the intermediate skier. Not all of us are pro enduro riders, and perhaps we would appreciate some extra grip and flotation.

For the moment, we do have choice – and plenty of it. There’ll only be more appearing this year, too, as more brands jump on the plus-size bandwagon. Unlike the US and much of the rest of Europe, though, it seems that experienced British mountain bikers don’t tend to go out and buy new bikes every two years. The majority of Brits prefer to buy a frame and swap the bits across, perhaps switching a fork next year and a pair of wheels after that. A shift to a new wheel size means buying frame, forks, wheels and tyres at the very least in one go, and so there’s understandable reluctance for change. However, would we really want to go back to 25.4mm handlebars? Quill stems? 1.8in tyres? Some change is good.

As the Sage of Alsager (Sideways Cycles’ Tim Johnson) put it so well to me: “Do you think this is the end of it? Do you think that the bike industry will say ‘Right, that’s tyre sizes perfected. Let’s move on’? No, this will never end, so just get used to it.”

The Plus Size Revolution
Oi, looking at my knobbly rubber?

Below are some quotes from industry folks on their opinions on Plus tyres and the wheel size debate. Do you agree with what they have to say? If you have anything else to add feel free to visit the comments section.

“Every surfboard feels different, some have five fins, some no fins, five-foot through to 14… and it’s a sensual thing, feeling the boards’ strengths and weaknesses, working with them and getting the most out of it, focusing on what it excels at. There is a honeymoon period where you explore what a board can do, you are learning the board. So many bikes are the same, they do the same thing… ride two bikes blindfold and you will crash… but you won’t know what bike you crashed on.”

Charlie ‘Bikemonger’ Hobbs


“The industry has been disappearing up its own arse for years… giving us more BB standards and headsets, and axles than we can cope with. So why the weird anti-wheel size debate when the industry eventually gives us something that really does make a difference?”

Charlie ‘Bikemonger’ Hobbs


“Isn’t it exciting to see a cycling discipline (MTB) that is so willing to embrace product innovations so quickly and readily? No other discipline comes close.”

Dave Taylor, Marketing Manager, Schwalbe


“If you’re happy with the Trailblazer or other 2.8in tyres on the rear rather than the full 3.0in tyres that are coming now, you don’t need Boost 148 or dedicated 1x. You simply need a 29er with sorted geometry and good clearances.”

Cy Turner, Cotic


“My guess is that the sweet spot for our bikes will be a light, narrower rear which helps keep the bike lively, and a wider front to help support the tyre where we have had ‘squish’ issues with the narrower rim.”

Cy Turner, Cotic


“Basically all the same pros/attributes as full fat 26×4.0in, albeit in a lighter, faster accelerating, more manageable and agile package (no John Wayne q-factor, sub-900g tyre weights) that should strike a better balance for all-round riding.”

Albert Steward, Genesis


“I’d say 3in tyres would make for some very capable, lightweight short-travel full bouncers. Time will tell but I reckon Mr Pro Enduro could be eating his words (and 1.8in mud tyres) in six months’ time.”

Albert Steward, Genesis


“For Turner Bikes these changes are extremely difficult and costly, and certainly I could wring my hands and blame it on the major corporations and their push to sell more bikes. But, changes to the equipment makes a difference in our riding experience… New bikes are better than older bikes.”

David Turner, Turner Bikes.


“Riding a plus bike in SoCal, I didn’t really get it at first; it rolled better than the traditional fat bike but you still noticed the extra weight. Traction was great, but it wasn’t light years ahead of a good 27.5 tire. I have since ridden the same bike up here in Canada on the North Shore and Whistler and I am starting to get it now. It does make a big difference when you start throwing a lot of rocks and roots into the mix, plus you can really plough through stuff with it.”

Mike Dunn, RST USA


“(Plus-size tyres) don’t offer the float in truly questionable terrain, or snow, in the same way a true fat bike tyre does, but I find myself aiming for the ill defined trail with a positive attitude.”

Dr Jon


“How hard is it going to be for the trade and for consumers to keep up with this ‘progress’ – most riders in the UK are still coming to terms with the apparent sudden death of their beloved 26in wheels and the move to 142mm dropouts and thru-axles. Now we’re telling them that it’s all 7+ and 9+ and Boost 148. I suspect only the committed and lucky few will take these trends up this year. But I see no reason to fear progress or options.”

Dr Jon


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