IRC Boken Tires: At The Finish

IRC Boken Tires: At The Finish – by Guitar Ted

IRC is not a name that floats to the top of the list of gravel tires when discussing choices for back road riding. IRC wants that to change and when Grannygear met the IRC folks at Sea Otter this past April, they agreed to have us try out their latest offerings for gravel/all-road travel. We have already taken a close look at the two Boken models (HERE) and given you our mid-test impressions (HERE), but now it is time to wrap up our thoughts on these new tires for the gravel crowd.

The IRC Boken 700 X 40mm
The IRC Boken models (700 X 40mm here) are fast and smooth.

Two words kept cropping up whenever Grannygear and I discussed these Boken 700 X 40mm and Boken Plus 650B X 47mm tires. Those words were fast and smooth. The IRC Boken models are some of the fastest and most comfortable tires we’ve tried. There are a few reasons why this is. First- The casings flex easily and absorb road vibrations and bumps very nicely. This also lends the Boken models a bit more grace in the traction game since the casings can find grip where stiffer tires slip and fail. That said, we aren’t talking great gobs of traction here, since there are no real knobs to speak of, but these tires will do more than their looks would lead you to believe.

Detail shot of tread on a 700c X 40mm IRC Boken
Note how some of the tread “blocks” are muted here. Life expectancy of the Boken tread will be limited by the use of a softer rubber compound here.

The tires are also very fast, and the softer rubber compound matched up with the very forgiving casings to make for speed that is unmatched by anything else we’ve ridden. Keep in mind that this has been done at the expense of flat protection belts, (they do have side wall protection) and at the expense of longevity. Both Grannygear and I have noted a rounding off of the small, pyramid-like tread blocks on the 700c Boken, which would indicate a fast wearing tire here. IRC essentially admits that this is the case, but advises that that their goal was to make a fast, smooth tire and a lower tread life expectancy is going to be par for the course. So, another case here where a great performance advantage comes with some compromise. Buyer beware.

A couple of other things one should note about these tires- One is that the 700c X 40mm Boken will likely end up being wider than 40mm on your rims. With several bikes now out that limit tire clearances to 40mm, or slightly above that, you may find the 700c X 40mm Boken a very tight fit. Our test models stretched to a plump 42.6mm @ 38psi. The Boken Plus 650B X 47mm (claimed) also stretched quite a bit with our test model reaching a wide 49.5mm @ 35psi. (Note- IRC offers both tires in narrower widths for bikes with less clearance.)

Detail shot of an IRC Boken Plus 650B X 47mm
The pliable casing is immediately noticeable with the Boken Plus.

The other thing is the aforementioned lack of any flat protection belts in the casing. (EDITOR’S NOTE- We were informed by our contact that the Boken models do have sidewall protection. This is not indicated on their website, by the way) We did not experience any cuts or punctures during our test. It should also be noted that softer, more compliant tires tend to resist punctures. However; anyone seeking a tough, flat resistant tire may not be happy with the Boken models. So, keep all that in mind if you are looking at a potential swap to these tires for your rig.

At The Finish: IRC has a tire in the Boken that is very interesting. Fast, smooth, and compliant for days, but with the caveat of a shorter potential lifespan. This then becomes a question of whether or not that compromise is worth dealing with. Many will not be attracted to such a deal that IRC offers, but for some of you, this tire might be more fun, a benefit, and therefore well worth putting up with the potential for a shorter life cycle and perhaps something more prone to cuts and punctures on the tread area.

In our view, this is a tire that has qualities that trump all others when it comes to racing, or for the rider who primarily spends their time on dirt more so than gravel or especially pavement. This is a tire that punches above its weight in the area of traction also, but don’t expect it to corner exceptionally well on loose terrain or to winch you up out of a muddy valley. Conversely, we know of tires that are nearly as fast, have puncture protection belts, and have longer lasting treads than the Boken models do.

Asking us whether or not we’d run these tires, well, it is a hard question to answer. The speed and ride quality are addictive, certainly. However; at just a hair under $70.00 per tire, and factoring in what we have observed for wear so far into this review, please color us conflicted.

Note- IRC Tire sent over the Boken Plus and Boken tires at no charge to for test and review. We were not paid, nor bribed, for this review and we will strive to give our honest thoughts and opinions throughout.


Author: Guitar Ted

Guitar Ted hails from Iowa. Home of over 70,000 miles of gravel and back roads. An inaugural member of the Gravel Cycling Hall of Fame and Co-creator of Trans Iowa in late 2004- Guitar Ted has been at the forefront of the growth of gravel events and riding since then. Creator of Gravel Grinder News in 2008, he produced the premier calendar of gravel and back road events. GT joined forces with Riding Gravel in late 2014.

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9 thoughts on “IRC Boken Tires: At The Finish

    1. I used the Specialized Tracers in 38mm this year and they were quite fast but a little rough in the meadows at the end. Clearance limits me to about 42mm actual width so a fast, comfy 40mm that plumps out a bit would be sweet!

    1. lyford- I’ve ridden both extensively in Routt, County, CO. The Schwalbe G-Ones (in 35c) feel a little more compliant to me. The Bokens (in 36c) are still very smooth but feel firmer and definitely corner (on dirt, etc) better. Both are fast though and are great for the CO hard-pack and loose dirt. G-Ones might be a touch faster on asphalt, but its hard to say, going from memory, across two seasons. In thicker gravel you might want more tread than either provide. Before I went to the Bokens I put several hundred miles on IRC’s Serac Edge XC 32c. LOVE that tire! It is really fast and very tough. I rode them on some local single track with rough, off-camber ledge rock sections and plenty of sharp goat-heads poking through the trail – I was just waiting for a flat but it never came. On asphalt and hard-pack they haul ass. Period. Really, fun versatile tire. Not as supple, of course, and rough descents can get fatiguing. The Boken appears to have an identical tread design as the Serac Edge CX, just wider. The Seracs showed signifcant wear to the center of the diamond tread after +/- 600 miles. But I tend to over inflate these things (anywhere from 50-60PSI for the 32c), so that could have been a contributing factor to the early wear. The Bokens only have a +/- 200 miles on them, so too soon to tell on the wear. Initially, I ran the Boken 36c at ~50psi and they felt sluggish, but after lowering to 40-42 psi they feel faster and also much smoother.

  1. Are these the first or second versions? Just received the 40mm second version and they’re nearly 500g, and have added protection and bead reinforcement so curious if they’re even the same tyre reviewed here

    1. @Rob Holloway- Our versions were thought to have no puncture protection, (and we were right, sort of), but they do have sidewall protection. Might be what you have? Hard to say, as the information we received came from IRC’s US rep and the website did not reflect this at the time we were writing up the review.

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