Posted on August 1, 2022 by Cory Benson
Much like the gravel discipline itself, Challenge’s popular Gravel Grinder is a tire spilled over out of cyclocross. But while it was a literal cut & paste of straight-line speed & grippy cornering, now it refines the transition to create a more versatile, much more predictable gravel bike tire. Back on tarmac, Challenge adds an all-new Criterium RS tire for high-performance hookless tubeless road riding, while some giant 45mm Strada Biancas blur the lines between on-road & off-road.
The Challenge Gravel Grinder started life as just a rebadged and renamed Chicane cyclocross tire. The 33mm Chicane itself was actually a project developed by Helen & Stefan Wyman of gluing the Limus mud tire shoulder knobs onto the fast-rolling file tread center of a Grifo XS, with surprisingly successful results in cross racing at <20psi.
The Gravel Grinder itself was offered in 33, 38, 42 & 46mm sizes which necessitated slightly different treads for each (with different interstitial spacing & file sizes). But they never really nailed the transition from file center to lug shoulders, leaving a gap that sometimes made for an abrupt change in grip depending on conditions. That was, until now!
The tread change is relatively minor, but I think it will make a huge improvement in the performance of the Gravel Grinder tires going forward.
Challenge has moved the intermediary triangles all the way over into the files, cutting halfway into the first row of pyramids for a seamless transition as you lean. Plus, the triangles are bigger overall for more support, and now are the same height inboard as the files, and taller outboard to match the cornering lugs. Those cornering lugs are also larger for extra stiffness & supportive grip, and newly tapered to flow more smoothly lining up with the transition.
They’ve also tweaked the files a bit themselves, opting for the smaller files with a newly narrower nested pyramid design that is a bit less angular than before with a bit of space between each file so they can flex more independently for improved grip.
The new Gravel Grinder is available from September in Challenge’s top H-TLR handmade tubeless casing in 700 x 33, 36 & 40mm sizes, featuring a durable but supple 260tpi polyester construction with reinforced beads, bead-to-bead latex-based inner coating, and flexible Ganzo puncture protection under the gravel-specific (higher durometer) SmartPlus natural rubber tread compound. (Look for the transition knob cutting into the files to be sure to get the updated version!) Claimed weight of 470g per tire (40mm) and retail price of $90 / 78€. No immediate plans for a 46mm version at least this year.
The cyclocross Chicane has been updated with the same refined tread too, but for now only the top handmade TLR tubeless version. The tubulars still all use the more blocky design, while the vulcanized versions use something in the middle with the pronounced gap from files to shoulders.
While many cyclists – including myself – have the most experience with Challenge tires in gravel, cyclocross, and alt-road (think bigger volume and rougher surfaces)… they also have done plenty of traditional performance road tires, too. Now with a new hookless tubeless Criterium RS, it seems like they’ve combined the best tech of both worlds.
The supple 350tpi handmade cotton Criterium RS promises an ultimate level of road performance. It gets a new slick center with textured cornering tread pattern using a new SmartPrime compound that mixes natural and synthetic rubbers to find a sweet spot of increased grip in both dry & wet conditions, “one of the lowest rolling resistance tires in the market”, plus increased durability & puncture resistance.
That’s a lot of performance claims from a single, supple tire but likely one worth checking out.
Hitting more of the tech details, the Criterium RS tucks a flexible fabric Ganzo puncture protection belt under the tread (like the Gravel Grinder) and gets the same black Chafer Protection Strips at the bead to resist wear from sharp carbon rim hooks. The bead itself uses reinforced Zylon (1.6x stronger than Kevlar) to resist stretching even at higher pressures.
The new Challenge Criterium RS comes in 25 & 27mm widths in hookless-compatible tubeless or conventional tubulars and in black or white sidewalls. Claimed weight of 225g per 25mm tire, 260g per 27mm and a retail price of $95 / 85€ with availability from October 2022. There will also be a TLR kit that includes a pair of tires and two bottles of Challenge’s sealant for easy tubeless setup.
We knew the bigger volume 700 x 45mm Strada Bianca was coming soon, as I tested the 40mm version. It’s a surprisingly versatile gravel tire at such high volume since you get a lot of grip on a mix of surfaces running low pressures that allow the tiny herringbone tread pattern to find unexpected grip. Now from October, you can pick up the ~550g 45mm tanwall tire for $90 / 78€ (in addition to 30, 33, 36 & 40mm sizes).
Plus, now the full range of gravel and cyclocross treads have gotten the same upgraded, extra-supple handmade tubeless casings with reinforced beads that have been quietly rolling out over the past two seasons, both in UCI-approved 33mm versions and bigger 36/40mm versions for more mixed surface riding.
Cory Benson is the EU Tech Editor of Bikerumor.com.
Cory has been writing about mountain bikes, enduro, cyclocross, all-road, gravel bikes & bikepacking for over 25 years, even before the industry gave some these names. Prior to Bikerumor, Cory was a practicing Architect specializing in environmental sustainability, has designed bike shops & bike components and worked as a bike shop mechanic.
Based in the Czech Republic for 15+ years, he is a technical mountain biker, adventurous gravel rider, short & medium-haul bikepacker. Cory travels extensively across Europe riding bikes, meeting with key European product developers, industry experts & tastemakers for an in-depth review of what’s new, and what’s coming next.
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These all look amazing, to be honest. I’ll take those Gravel Grinders and Criteriums.
The Criteriums have the same stats as a Veloflex Corsa Race TLR… Which are the best tyres I’ve ever ridden.
why is there a 45mm strada but no gravel grinder?? strange. I was about to throw down some cash for a 46mm challenge gravel tire, but alas.
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