WTB Riddler 37mm Tires: Getting Rolling


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WTB Riddler 37mm Tires: Getting Rolling-

The tubeless gravel road class tire segment keeps getting larger and as we reported here back in April, WTB has made good on its promise to bring the 37mm Riddler tire to light and have sent a pair to RidingGravel.com for test/review. The 45mm sized Riddler tires will make it to market in August, according to the latest from WTB. So, here we will focus on the 37mm version of the Riddler and give you our initial impressions of WTB’s latest gravel road tire model.

The TCS Riddler 37mm tires have a unique tread pattern reminiscent of a Clement design.

The Riddler tire first made an appearance as a mountain bike tire design and was named after WTB athlete, Nathan Riddle. The design utilizes a small, micro-block tread design in the center portion of the casing to promote speed and blocky edge knobs to give control in the corners. WTB “shrank” this design to render a similar look on a skinnier casing suitable for gravel roads and the bicycles designed for them. The center part of the 37mm version reminds us of the Clement MSO, which is a fast rolling tire, but the additional edge knobs are a bit more unusual, and only Challenge Tire’s “Gravel Grinder” model has anything similar to this. The unique combination of these two characteristics in the Riddler 37mm tire point to an interesting possibility- Fast rolling with stability in looser gravel and in corners. Will the Riddler live up to our expectations? This is what we will find out later during my ride testing.

Technical Features and Measurements:

The Riddler utilizes WTB’s excellent TCS tubeless system design for easy tubeless set up.

The Riddler features WTB’s excellent TCS tubeless bead and casing design which we have had good experiences with here at Riding Gravel. The casing is WTB’s “Light” version which promotes a supple ride feel and renders the lightest tire. The tire also features WTB’s “Dual DNA” rubber compound which mixes a center section of the tread which has longer wearing attributes and side knobs that are slower to rebound and lend a stickier, higher grip feel in corners. The bead is designed for tubeless usage, has an Aramid, folding type design, and has a dimension which is based very closely to a UST dimension. This should make the Riddler a very difficult, if not nearly impossible, fit on a Stan’s rim, for reference.

The WTB website did not give us any expectations on weight, but the two samples sent to us clocked in at 460gm and 470gm respectively. This compares favorably with other tires in this class that are tubeless rated. The width of the tires inflated to 40psi on the Velocity A23 rims is 37.2mm averaged out over several measurements taken on the front and rear tire. That claimed width of 37mm turns out to be spot on. That puts the Riddler in the same territory in width and volume as the Clement 36mm MSO,  slightly smaller than a Clement 40mm tire, slightly smaller than a Maxxis Rambler, and far smaller than the Panaracer Gravel King 40’s.

Tubeless Performance: The WTB TCS system is obviously going to be a very robust, reliable way to set up the Riddler, so a Velocity A23 was tried to see if a similar good result could be seen. The Velocity A23 has been successfully used in testing here with a TCS Nano 40 tire, so the expected result was that the Riddler would work. It not only worked, but unlike the Nano 40 tires, the Riddler went on without the need to use an air compressor, almost going on as easily as the WTB Horizon tires did on Velocity Ailerons. Air retention was very good, and so far there is no reason to believe that the Riddler won’t be at least as impressive as the other TCS tires tried in our testing so far.

So Far…… Initial rides were done with the front tire at about 38psi and the rear at 40-42 psi. The ride feel is supple, and the Riddler seems willing to damp out vibrations well. I can say that low rolling resistance is going to be an attribute of this tire, as it was easy to spin up and held speed well on my roll down test until it was interrupted by traffic. I will revisit that later, but I am of the opinion already that this tire will be a very good performer. The TCS system and tire design is well proven, and the Riddler carries on the tradition of WTB tires fitting on Velocity rims well. Gravel roads will be up next, so stay tuned for the Checkpoint post coming in a couple of weeks or so.

NOTE: WTB sent over the Riddler 37mm tires at no charge to RidingGravel.com for test and review. We are not being paid nor bribed for this review and we strive to give our honest thoughts and opinions throughout.

Discuss and share your questions or thoughts about gravel bikes, gear, events and anything else on the Riding Gravel Forum


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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10 thoughts on “WTB Riddler 37mm Tires: Getting Rolling

  1. In reference to your statement that the TCS bead won’t fit Stans rims, just wondering why you assume that. I have been running the nano 40c TCS light on my Stans grail wheels tubeless and they mount just fine with no trouble at the rim bead interface. If the riddler has the same bead as the nano then there should be no fit problem. It could be that the TCS bead is not exactly the same dimensions as the UST. I had a Geaux mtb UST tire that would not fit my Stans crest wheels due to the tire diameter being too small to even fit over the rim. This is certainly not the case with the TCS bead, at least on the Nano. Maybe you should consider updating your review considering that many riders might avoid certain combinations based on what you say.

  2. @Jimmy Smith- The statement comes from trying those tires on Stan’s rims. There is also quite a bit of feedback confirming that the tires are a difficult/not optimum fit on Stan’s rims. Note- I did not say it was impossible. You can put a 700c tire on a 27″ rim if you are determined enough. (I’ve done it back in my early mechanic days.) However; if one were to have an issue in the field necessitating a tube to be utilized, it may prove to be an issue that requires a bail out. Maybe. I have actually seen this happen where a rider had to bail out of an event due to such a circumstance, so it does happen.

    The bottom line is, as a media source that does reviews, we have to be careful to give reliable, factual, information to the best of our abilities. In my personal experience as a rider, reviewer, and bicycle mechanic, with the added input of riders from all over, it is my opinion that the WTB tires and Stan’s rims are a poor fit and should be avoided. Well, in fact, many times it is near to impossible to mount those two brands products to each other.

    So, my statement will remain.

  3. I’m trying out the 700 x 37 Ridler and they’re mounted on the WTB rims and I’m running them tubeless at 35 psi. By comparison my other bike has 650 B x 42 WTB resolute tires on WTB rims, tubeless at 30 to 40 psi. I have much more time on the resolute and feel very confident on that tire on rough gravel. I’m considering trying 30 psi on the Ridler as it just feels too hard. It also feels like a very square tire. Do you have any comments or insights to share regarding my comments. Thank you much, Greg

    1. @Greg- Well, as I see it, you have a couple of things going on here. (1)- The 650B tire is nominally 5mm wider and probably more volume to the casing than the Riddler 700 X 37mm. (2)- Yes, the Riddler is a bit more “squared off” in profile.

      So, I like to try to think of tires as springs. Smaller, less forgiving springs = Less voluminous tires versus bigger, more forgiving springs = bigger volume tires. Even 5mm makes a BIG difference here. Lowering your air pressure on the Riddler will not equal the same ride with the Resolute 42mm tires at the same pressure due to the volume differences. Besides that, at a certain point you are going to start diminishing the performance attributes of the 37mm Riddler as lowered pressures will at some point make for higher rolling resistance, squirmy feel, and a higher chance for cutting the sidewalls or burping the tire. (By the way, you don’t mention rider weight or terrain- both of which factor into all of this)

      Then there is the casing shape, which you note. For some the more squared off profile works and for some it doesn’t. We find that in looser, deeper, and chunky gravel that a squared off profile works up and over the rocks rather than what a more traditionally crowned tire would do. Those more rounded in cross section have a tendency to plow, pushing through more gravel than they do riding up over it. Your mileage may vary (greatly) in this regard.

  4. At 200lbs, would you still recommend 38 / 40-42 (front/rear) psi, or would you suggest adding more? I use it as gravel bike generally, but often for city commute as well.

    1. @David – I outweigh you by a fair amount and never go above 40psi for any riding with any tires I have now. That includes the WTB tires in question.

      That said, you do you. What you feel works best, you should do. However; there is mounting scientifically arrived at data and many riders experiences that would lead me to not air up this tire that high at your weight. Loads added will modify my response somewhat. I am assuming your weight and that’s that.

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