IRC Boken Tires: Checkpoint

IRC Boken Tires: Checkpoint- by Guitar Ted and Grannygear

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Editor’s Note: IRC sent two sets of tires each to Guitar Ted in the Mid-West and Grannygear in SoCal. This “Checkpoint” post will combine their thoughts so far on the Boken 700X40mm tires and Guitar Ted’s thoughts so far on the Boken Plus 650B X 47mm tires. If you missed the “Getting Rolling” post, please click for that HERE. Now on with the Checkpoint review…..

An image of the IRC Boken 40mm tire in the country
IRC Boken 700X40mm- From The Mid-West With Love.

Guitar Ted’s Take: Here in the Mid-West, Spring has been cooler than normal, wetter than normal, and the roads have been the most challenging that they have been in years. Perfect for testing new tires! The Boken 700c X 40mm tires, as mentioned in the “Getting Rolling” post, are actually 43mm, and they present a flatter profile to the road surface than they may have at 40mm. The lack of any significant tread along with that flattish profile meant that sometimes traversing mud could be akin to riding on ice. The bike would kind of take off on me, which can be alarming. But then again, one shouldn’t expect anything more than that with such a semi-slick design.

The Raleigh Tamland Two test mule with IRC Boken 40's mounted.
The IRC Bokens seem to slough off the muck fairly well, but then they don’t have much to hold on to it with.

Once things firmed up a bit though, the Boken was predictable and fast. That supple casing contributes to these tires having a smooth, easy roll, and I am suspecting that the soft rubber compound contributes to this characteristic as well. The messy roads were no problem for the Boken to handle as the tread doesn’t have much there to hold on to the mud with. That allows the Bokens to slough it off easily and traversing some very nasty mud spots became a game of just keeping the bike upright and moving. Generally speaking I usually end up having to stop and clear out the frame of mire with other tires that hold on to mud and allow it to build up.

More normal conditions showed me the smoother ride qualities of the tire and I was pleased to have that as the roads are being patched with fresh, rough gravel. The traction isn’t great in mud, for obvious reasons, but in the rough gravel and even on more “normal” gravel and dried mud the tires have a really good feel in corners and don’t seem to lack for grip.

Grannygear's Lynskey GR250 with IRC boken 700 X 40mm tires
The Boken 700c X 40mm tires on Grannygear’s Lynskey

Grannygear’s Take: Guitar Ted already unpacked the IRC Bokens, a tire that IRC is pinning their hopes on as they seek to make inroads into the gravel market.  My experience so far?  I am thinking they might have pinned their hopes to a rising star.

I weighed them at 483g and 489g and mounted them up to the Easton EA90 SLs with a splash of Orange Seal, setting the bead easily with a floor pump and WITH the Presta cores intact.  Impressive.

Boken close up.

I measured them at 40.5mms right after mounting and now, after some time, they have plumped up to nearly 42mms.  Very nice.  I have run as low as 25psi and as high as 35psi but 30psi is about the norm.

Immediately you feel how fast they roll on hard surfaces.  Pavement and hard dirt roads are blazed over with a quiet and smooth ride.  I expected that though, just by looking at the tread.  But I was not expecting how much hook-up they deliver on out of the saddle climbs and through fast corners.  It’s surprising really, and I have to think that might be coming from the soft rubber compound.

I have also seen excellent performance through sandy patches.  Some tires just seem to do well here and others not so much. The Bokens seem to have the casing size to float well, but they also steer well in sand.  

Close up of tread wear
Soft rubber = fast wear? Looking that way.

So what is not to like? Well I am not sure how long these will last. The rear center file tread is pretty muted now with a half dozen 1 to 1.5 hour rides on the clock.  Is that the price of fame?  Maybe. I have not seen any chunking of side knobs or anything fatal looking though.

I spoke to the IRC marketing rep about this softer compound and performance vs. longevity.  It is IRC’s take that the performance gain of the softer rubber is worth the trade-off of a super long wearing tire. And that is fine for the consumer too, as long as they understand that.  And it is not like these are worn out after a couple rides…nothing that extreme.  As well, even though the center tread is pretty dulled on the rear tire at this point, I really have not noticed a drop in climbing traction.

I am thinking these are really, really good all-rounders in dry conditions and I am very much enjoying riding them.

Yje IRC Boken Plus 650B X 47mm tires on a pink Black Mountain Cycles MCD.
The IRC 650B X 47mm tires are some of the fastest tires I’ve ever tested for gravel

IRC Boken Plus Take: Grannygear hasn’t had much opportunity to ride the 650B X 47mm Boken Plus yet, but since I (Guitar Ted) have, I’ll go ahead and give you dear readers some thoughts to chew on in the meantime about these poofy tires.

And they are certainly poofy! They stretched out over the Easton EA70 AX wheels to become a shade over 49mm wide with a big, voluminous casing. This along with a very supple ride feel has contributed to the fast nature of the Boken Plus. In fact, I’d wager that these are the fastest, smoothest rolling tires I have ever tested. They are notably damped feeling also. If you want a smooth, vibration soaking tire, look no further.

A two track with the pink Black Mountain Cycles MCD
The Boken Plus had no problems muting the terrain and remaining fast feeling.

Of course, the Boken Plus has nothing to speak of for tread, so this isn’t probably going to be the tire for climbing on broken up rock, looser terrain, and the like. However; loose gravel, sand, and smooth dirt are traversed easily along with the expected great rolling performance over harder surfaces.

The Boken Plus samples I have are not light tires by the way. (See the “Getting Rollingpost for the weights and more) They are heavier than the WTB Horizon 650B X 47mm tires, and weigh in the neighborhood of some 29″ X 2.1″ tires. That said, the casings are holding air exceptionally well, and there is no hint of seeping sealant. I suspect also that these tires are a bit more resilient as a result of the beefier construction. All this with no dings on ride quality make the Boken Plus a pretty remarkable tire for the 650B rider.

So Far…… The Boken tire models are nicely constructed, feel tacky with their claimed stickier rubber compounds, and turned up to be both heavier and wider than advertised. With no puncture protection belts, we expected a smooth ride, and the IRC tires have delivered in spades. Tubeless performance was very good. Traction is better than expected for tires with minimal or basically no tread. The operative words so far are “fast”, “smooth”, and perhaps a bit on the quick wearing side.

Next we will be bringing you the final part of this review in which we plan on having Grannygear chip in on the Boken Plus tires. Stay tuned for that in a few weeks or so.

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.


About The Author: Grannygear hails from SoCal and spent most of his cycling days as a mountain biker from the formative years of mountain biking all the way up to the present day. His day job is in the tech sector, but he has spent time writing about off road 4X4’s, 29″ mountain bikes, and cycling in general. Grannygear and Guitar Ted have worked off and on together since 2009 after a chance meeting at Interbike. With gravel cycling on the rise, Grannygear has been exploring how this genre’ works in SoCal and now does guest pieces for in his spare time.



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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3 thoughts on “IRC Boken Tires: Checkpoint

  1. just recently started riding the 700×40 bokens on my squid tracklocross bike and they are the jam! very stoked on them thus far. while i haven’t had a ton of different conditions on them, i did race a dry/sandy/rocky tracklocross race in oakland and they took me to a 3rd place finish and a solid W at a dry/grassy tracklocross race in chicago. they ride fast on pavement for sure and i’m looking forward to testing them out at the ride ten thousand this weekend in western illinois. also, have a set of the 650×47 en route that i’m stoked to try out! i appreciate all your 3 part reviews of gear. sometimes stuff i love early on i wind up hating and vice versa, so thanks and keep up the good work!

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