IRC Boken gravel tyre

The IRC Boken is a gravel tyre that is claimed to offer good performance on a wide range of surfaces. It is a very fast tyre with minimal tread, but the actual usage is more limited than you might expect.

IRC makes some bold claims for the Boken, which is constructed using a compound it calls 'Ultra Gummy' that offers 'insane bite on obstacles'. The conditions that IRC claims it is suited to range from 'Hard Pack' to 'Loose Dry' (in its own range of criteria, which takes in 'Rocky Broken' and 'Loose Over Hard'), buts fall short of recommending it for anything loamy or wet, and looking at the tyre you can see why.

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The tread is minimal, looking very similar to a cyclo-cross tyre aimed towards sand and dunes, with a file type tread design, with some wider but still low profile tread on the far edges.

Installation was relatively simple, taking a little more effort than some to get onto the rim but by no means a challenge, and then it inflated quickly and with just a track pump.

Given the stated size, 700x36, they actually pumped up much wider, measuring 39mm. This is on a rim with a 22mm internal width, which is wider than some but by no means extreme for a gravel setup. While this difference in stated size is quite common, I checked with IRC and for the Boken 36 it has them tested at 37.6mm on a 21mm rim, and 39.5mm on a 25mm rim, both at 60psi.

The tyres show a pressure range recommendation of 45-60psi and officially IRC cannot recommend less for legal reasons. This range will seem too high for some, especially for lighter riders and those who run tubeless. (IRC is not alone – many other brands will show a pressure that is higher than many riders will choose to run, an issue that likely has its roots with the outdated ERTRO tyre size and pressure standards that are due a change.)

My initial thought when riding was how quiet they are, both on surfaced roads and hard pack. While some tyres can drone, the Bokens are incredibly smooth and quiet. They feel fast, too, really fast. Given the tread design this might not be too surprising, but even when compared to slick tyres of a similar size the Boken is rapid.

At 477g the weight is reasonable, perhaps helped by the fact that there is no puncture protection layer, and while it may just be luck, I had no punctures despite some really challenging and varied rides while testing.

Although not listed, the threads per inch (TPI) of 60 is quite basic and low; many similar tyres and especially at this price will be 120TPI or even higher. In theory, a higher TPI would make them lighter and more supple, although it's not always so simple. For example, they feel far more supple to ride than the Hutchinson Touareg I tested for off-road.cc, which has a 120TPI casing.

So do they offer the 'insane bite' that is claimed? Not really. On dry tarmac they feel incredible in the corners, like they have endless grip, and I was really able to lean sharply into the corners, but this isn't a pure road tyre. Off road, things are a little different, and on anything even slightly loose they slide out easily in faster corners, including your typical British forest road. While they're not claimed to work well on wet surfaces, on a damp track and so long as there is no mud they do grip nicely.

Initially I tested them at the lowest recommended pressure of 45psi and the drifts were quite extreme at times. Legal recommendations aside, I dropped them lower, down to 35psi front and 38psi rear, and this did improve things a little, but they will still drift through looser corners.

The grip, or lack of, can be a little disconcerting at times, but strangely I did find I got used to them and when they do slide it is predictable. The only time it became an issue was on tracks I did not know and with corners that tightened unexpectedly, or where the line became looser mid corner.

Any attempt to ride the Boken on muddy tracks and the lack of grip is very obvious: traction uphill or around corners is compromised further. It isn't a tyre recommended or aimed at wetter riding, so it isn't something I can be too critical about.

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At £50 per tyre, it isn't a budget option and there are many cheaper ones available, such as the Hutchinson Overide at just £33.99 or the Michelin Power Gravel that Stu liked recently. It is by no means the most expensive, though, with the Pirelli Cinturato Gravel H tyre being £5 more and sharing a very similar style and design, although that does at least have a higher 127TPI casing.

If racing or perhaps even KOM/PB hunting is your thing then the Boken might appeal, as it certainly does deliver a seriously quick ride. It might lack grip in some or perhaps most typical conditions, but after a while I did learn to read and adjust to the grip on offer and if you know it's going to be dry it might be worth a shot for the pure speed on offer.

Verdict

Superfast gravel tyre that could be ideal for certain terrain and conditions, but limited use for typical British riding