Words by Flow | Images by Flow

In the scrappy battlefield of wheel sizes, the 29er and 27.5 armies are dug in tight, with well-established trench lines (forgive us, we’ve recently been listening to a podcast about WW1). But 27.5+ has been a late entrant to the fray and now it finds itself running around in no-man’s-land, searching for a place to establish its own position.

Will it survive past the first salvo and build its strength? Or will its life on the battlefield be a short one? Or, perhaps, will it launch its own attack, and blow the 27.5 forces to pieces?


We’ve ridden a good handful of 27.5+ bikes now, certainly enough of them to give us a decent picture of their merits. We’re firm fans. In the sandy, rubble-filled, rocky and generally slower-speed trails near Flow HQ, the Plus format is ideal. The bikes float over sand, find braking and climbing traction where we’ve never had it before, and corner on the slippery turns like crazy.

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Hardtails are prime for a Plus invasion.

For us, the Plus format is really just an evolution of how we’ve been setting up our personal bikes too; we, like many people, have been running ‘Plus-ish’ configurations, with wide rims and big rubber, for a couple of years.

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We’ve long been semi-mid-fatting our bikes with mods like 40mm rims.

We’re well aware that the style of trails we often ride aren’t what everyone else encounters. On the hardpacked trails of Canberra or Adelaide, or the red dirt and clay of Cairns for instance, a Plus bike mightn’t be the right tool for the job.

On the fast, handpicked trails of Canberra for example, perhaps 27.5+ would be out of place.

On the fast, hardpacked trails of Canberra for example, perhaps 27.5+ would be out of place.

We’ve had numerous chats with designers about their frustration with having to add another wheel format to their range.

Either way, in many instances, Plus bikes do have some pretty clear advantages over a regular 27.5 bike, certainly enough to justify their existence. This doesn’t make everyone in the industry happy, and we’ve had numerous chats with designers about their frustration with having to add another wheel format to their range. One engineer, who we won’t name, summed it up when we asked him if 27.5+ would survive: “There’s something to it (27.5+). Which is frustrating in a way, because they’re not beneficial enough to take over, but the format has enough advantages in some situations that it’s not just going to disappear either.”

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The Norco Optic in a 29er has virtually identical dimensions and handling to the 27.5 version.

It wasn’t long ago we assumed we’d all be on 26″ wheels forever, so the possible demise of the 27.5 wheel isn’t so silly really.

So it that it? End of story? Are we going to have three common wheel formats – 27.5, 27.5+ and 29er –  from now on? Maybe.

And we say maybe, because what if we’re looking at this the wrong way. What if we shouldn’t be debating the survival of 27.5+, but should be asking if this is actually the beginning of the end for regular 27.5″ wheels? Hear us out here. It wasn’t long ago we assumed we’d all be on 26″ wheels forever, so the possible demise of the 27.5 wheel isn’t so silly really.

There’s plenty of evidence to support this notion. We see three main points. 1) Improvements to 29ers 2) The potential benefits for manufacturers 3) The sequence of development.

First point:

29ers don’t suck now. In fact, they kick arse. Without a doubt, 27.5 emerged at least partly in response to 29ers initially handling like a Winnebago, and that just isn’t the case any longer.

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Boost rear hub spacing has allowed 29ers to be more fun and agile than in the past.

Let’s take a look at what’s happening with frame design and geometry for 29er bikes. With the emergence of Boost hub standards, single-ring drivetrains, new fork offsets and other design improvements, we’re beginning to see the convergence of 29er and 27.5″ frame geometries. 29ers aren’t big boats any more, in fact, it’s totally possible to put together a 29er which echoes the dimensions of a 27.5″ bike now, and which handles, in many peoples’ opinions, just as well as a smaller wheeled bike.

We’re beginning to see the convergence of 29er and 27.5″ frame geometries

The new Norco Optic is a case in point; one of the overarching goals of that bike’s design was to make the 29er and 27.5″ versions handle as close to identically as possible. And the bike’s designer Owen Pemberton freely admitted to us that if they had their time again they might not have developed the 27.5″ version at all, so good is the 29er.

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Pivot’s Mach 429 Trail is another example of how 29ers emphatically don’t suck.

We can point to stacks of examples that show just how far 29er geometry and frame design has evolved, and how many of the handling traits we previously associated only with 27.5 (or 26″) can now be found in some 29ers.

Second point:

There are big benefits to bike manufacturers if 27.5″ goes the way of the dodo.

Consider this: unlike 29ers and 27.5″, 29ers and 27.5+ bikes can share the exact same frame. 

We’re already starting to see manufactures cotton onto this and develop bikes that can happily run 27.5+ or 29er wheels. Take the new Pivot Switchblade for example, or the Santa Cruz Hightower, both of which will run either 29 or 27.5+.

 It’s like a half and half pizza – same pizza, two very different flavours, everyone is a winner.

Bikes like the Pivot Switchblade allow you to run either 29" or 27.5+ wheels in the same frame.

Bikes like the Pivot Switchblade allow you to run either 29″ or 27.5+ wheels in the same frame.

Sure, you might have to make some small tweaks (like using slightly longer travel fork for the marginally smaller 27.5+ wheels), but essentially with one frame you can offer up two very different bikes, for two very different rider or trail types.  It’s like a half and half pizza – same pizza, two very different flavours, everyone is a winner.

At this stage, most people are inclined to view these bikes as a manufacturer hedging their bets, but maybe they’re actually just ahead of the curve.

Last point:

Please allow us to indulge in quick bit of ‘what if’ thinking here for a second, and let’s pretend the sequence of development was reshuffled.

Imagine for a moment that the 27.5+ format was developed before 27.5″.  If that were the case, do you really think ‘regular’ 27.5 would exist? We doubt it. Every aspect of bike development has been moving towards increasing grip, larger tyre volumes, wider rims – if 27.5+ had been developed first, it’s fair to assume that ‘regular’ 27.5″ would be seen as a backwards step.

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If 27.5+ had arrived first, would we have ever developed ‘regular’ 27.5?

In this alternative reality, there’d have been 29″ wheels for the people who wanted lighter, faster-rolling wheels with a more precise feel, then there’d be 27.5+ for everyone else. (Ok, maybe downhill bikes would still have 27.5 wheels, but you get the drift).

Instead, just because 27.5 got here first, it’s now 27.5+ which has to prove its worth. It could have just as easily been the other way around.


This is all pure crystal ball gazing, of course, but with the mad pace of bike evolution now, who’s to say where we could end up. 27.5+ may well end up just being a diversion in the course of bike development. More likely, it may end up sticking around as a third option. Or maybe, it might end up on equal footing with 29er and we’ll see classifieds full of 27.5” bikes soon! What do you think?

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