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by James Huang
June 8, 2017
Photography by James Huang
The burgeoning all-road and gravel scene has spawned an explosion of higher-volume tires to suit. The WTB Exposure is aimed more towards the pavement side of the equation, with a 120TPI tubeless-ready nylon casing, a slick center, and a lightly knobbed shoulder tread designed for occasional jaunts off the straight-and-narrow. I tested the 32mm-wide version here, but WTB also offers it in 30mm and 34mm versions to suit different preferences and conditions.
Actual weight for my sample set was slightly under claims at 309g apiece (+/- 3g), and actual measured width on a 21mm-wide (internal width) rim was 32.5mm when inflated to 45psi.
Tubeless road tire and rim dimensions are all over the map these days, with many brands straying far off widely accepted European Tyre and Rim Technical Organisation (ETRTO) standards in search of a more secure fit. Refreshingly, WTB has stuck to a true UST-certified and tubeless-compatible bead measurement and shape for the Exposure, which I found to yield a consistently safe and secure fit on three different sets of wheels: Zipp’s new Firecrest Carbon Clincher Tubeless Disc-brake, the Enve 4.5 AR Disc, and the Industry Nine AR25.
The WTB Exposure 32 is at its best on a mix of pavement and hardpacked dirt.
The Exposure 32 mounted easily on all three of those wheelsets with no tire levers required, and yet still readily seated with a standard floor pump. For whatever reason, the supple casings were slow to fully seal, requiring 40cc of sealant per tire, several trial rides around the neighborhood to slosh the fluid around, and a couple of overnight waiting periods. Both ends have steadfastly held air after everything finally settled, though, and they’ve easily sloughed off the handful of glass slivers that had made it through the casing during almost two months of regular use.
The tires may have been a little tricky to get airtight at first, but that suppleness pays big dividends on the road. Admittedly, the Exposure 32’s vulcanized casing isn’t quite as pliable as an open tubular tire (where the tread is glued on to the casing separately instead of being molded together in one step), but it’s certainly among the more flexible vulcanized models I’ve used. The ride quality is wonderfully smooth with noticeably low rolling resistance as a result, and combined with the bigger contact patch relative to more traditional road bike tire sizes, cornering traction is simply fantastic.
In fact, it’s so confidence-inspiring that it can almost seem anti-climactic. One twisty local descent in particular felt so placid during one of my earlier test rides that I was sure I was slower than usual, but yet my Strava data confirmed afterward it was nevertheless one of my faster runs down that canyon.
The slick center and supple casing makes for a fast roll on pavement, and the micro-knob shoulder tread works reasonably well on dirt. Those little dots are prone to collecting mud, though, so it’s best to restrict the Exposure 32 to dry conditions.
That all said, the Exposure 32’s capabilities still strike me as a bit limited.
That micro-knob shoulder tread does a good job of grabbing on to hardpacked dirt surfaces where the tiny blocks can dig ever-so-slightly into terra firma. They don’t do much good if that surface is covered with anything more than fine dust, though, as the knobs simply aren’t big enough to lend much confidence in the marbles. Similarly, that rounded casing profile that provides such natural cornering manners on pavement makes for a sketchier feel when the ground is more slippery. In those sorts of situations, something like a downsized version of WTB’s Riddler might be better suited.
The Exposure 32 also isn’t at its best when its wet. The so-called Distance+ tread compound certainly helps with the low rolling resistance — not to mention long-term wear — but it’s a bit too hard to work well when the asphalt is covered in water. Likewise, the micro-knob tread not only doesn’t lend any additional grip on wet dirt roads, but also tends to collect mud instead of sloughing it off — something to be mindful of if you plan to mount these on a bike with marginal clearances.
The round profile makes for predictable cornering behavior with progressive breakaway characteristics when you’re at the limit. While overall cornering traction is excellent on pavement, it’s still a bit vague as you can feel those little shoulder knobs squirming beneath you under pressure.
As with most tires designed for mixed-use conditions, the Exposure 32 is an exercise in compromise. But if your riding tends to be in dry conditions on predominantly paved and good-quality dirt roads, this is one of the better (albeit expensive) options available to you.
Price: US$80 / AU$94 / £47 / €63