I've got a few hundred miles on these tires now-a pretty even mix of good aged chip & seal, fresh loose chip & seal, crappy patched and potholed chip & seal, and plush marble-sized river-rock gravel. I don't notice any real rolling resistance on pavement, and they stick like Velcro even in the really deep gravel. I haven't climbed much, but the bit of climbing I've done was fine and more importantly I had full control on the descent. I am running them with tubes at 55ish psi, haven't had any flats (punctures aren't likely here, no thorns or sharp rocks) and they do a pretty good job at smoothing out all but the worst bone-shakers. I'd definitely recommend these as a good all-around tire.
I live in Kansas and am from Emporia, the heart of Dirty Kanza and Flint Hills territory. I have used these tires thru 3 Dirty Kanzas, 2 Almanzos, 1 epic fail at Landrun(mud and weather, tires were fine) and countless other rides and races through Flint Hills Gravel. Two flats, both were pinch flats and totally my fault for running too low of pressure under my 190 lbs. About 53-55 PSI rear and 48 PSI front seems to keep me out of pinch flat trouble even in the Flint Hills Gravel. Rolling resistance is minimal on hard pack, yet traction remains great in the loose stuff. They do tend to wear a little fast, but at the price and weight well worth it. As a side note, on the two flats I did have, they go on and off the rims using no levers for a quick change under the stress of race conditions. In gravel cycling the tire of the moment always seems be in every conversation, but I have found no need to experiment or go tubeless with these tires around and will continue to run the Gravel Grinders.
Got these for my CX bike and a gravel race. Running them with latex tubes. Race had some single track with hills and some mud. Surprised how well the gripped. Have now been running them on pavement and see that my average speed is not much slower than on my road bike. No flats. Very pleased.
After riding with these tires for a few weeks I am quite pleased. I ride probably 75% pavement and 25% gravel and appreciate the fast rolling qualities of this tire with ability to ride at a variety of pressures depending on conditions. So far so good!
I needed tires for a dirt road event in Vermont and after reading a lot of reviews, I settled on the Gravel Grinders. I wanted something wide, with reasonable rolling resistance on paved roads and hard-packed dirt, but aggressive edge lugs for cornering in looser conditions. This tire has all of that and excellent durability, too. I couldn't be happier with their performance.
FYI, at 174, I ran these at 50/55, frontrear and that was perfect on a hard-packed course. My 110 girlfriend ran them at 30/35.
Prior to this I have been racing on Challenges high end open tubular Grifo XS in 33mm and soon its high end open tubular Gravel Grinder in 700x36mm tire. For training and commuting I do not want to burn through [$] high end tires when I can burn through the same tread for less than half the money and have an even tougher casing than the open tubular design saving them for race day! For training I have been riding every type of nail file tread pattern I could buy, My favorite up until this tire was released was in this order, Clement Las 33mm (actually a 36mm)for fast gravel country roads and finer gravel, or for rougher gravel Clement USH 35mm, Vittoria Pro XN 32mm(actually 30mm), Schwalbe Sammy Slick 35mm (actually a 31mm), and for rougher gravel and dirt Kenda Happy Mediums in 35mm or 40mm (both slightly undersized as well. I hope that Challenge continue to make Vulcanized Versions of its already top OT tires like The Grifo Pro now, as I wish they would make a Grifo XS 32mm vulcanized soon for my wife as this is her favorite tire! Do your self a favor and get this tire, it is the best!
These tires work well for pavement, gravel and dirt. They have minimal tread on the center and are lightweight for low rolling resistance and the knobs on the sides provide traction in looser terrain.
Originally went w the 33s for tackling the (awesome!) Hoosier National Forest roads. Loved the tires but found them too narrow for some of the loose gravel. Bumped up to the 38s and they are perfect. Expertly manage the slime of sloppy lime dust but also do a better job of floating over loose gravel. Excellent on dry hard packed gravel and tough enough for the occasional bit of singletrack. Roll nicely over paved sections. About 1000 miles without a flat. Have tried them tubeless but the sidewalls leak too much - not sold as tubeless so that's fair. Great tire!
I live in the city with streets and paved bike paths, but I'm at the edge of town with gravel section roads stretching to the horizons through farmland. These tires have been a welcome upgrade over the stock 33mm tires that came on my Specialized CruX. Smoother rolling center tread, knobby on the edges to bite in the loose and chunky gravel, and enough volume to lower my pressures for a smoother ride. Near perfect.
I purchased these after experiencing reliability issues with another tire. I found myself riding hard-core gravel and wanted a tire that could withstand the punishment, but still provide good rolling resistance on pavement. For me, it was between these and the MSOs. I ran the Gravel Grinder Race for 8 months with acceptable results.
A few notes Tubeless performance was unsatisfactory. This was disappointing, but they were not sold as tubeless ready, so what can you do? This is the main reason I don't run these anymore, and why i gave only 4 stars. Another observation is those larger side knobbies. To me, they seemed like a distraction. I did not like the way they felt underneath when they engaged. It felt like the tire changed its characteristics whenever in a hard cornering situation (which is where I want it to be the most consistent). Get rid of the side knobbies, they're dumb.
The tire looks good, rolls well, and is reasonably tough. It's a good alternative to Clement MSO or even USH. Do not expect to run these tubeless. I found they wore a little faster than I'd hoped for.
I've ridden these for 2 seasons and, overall, I like them. They roll fast on pavement and dirt, they wear well (still plenty of life left on mine - I rotate FR each season), I have yet to get a flat, and they're a good value on sale thru BTD. My one con is that they bite hard in corners, especially in loose gravel and dirt. My go-to loop is a mixture of pavement, graveldirt roads and some fast stretches of singletrack. I find that when I take a loose corner at speed, these will start to slide at first and then bite hard as the outer lugs grip. For that reason, I'd say they're best suited to dirtgravel roads (as the name implies) than high-speed singletrack. It's not a deal-breaker for me, but you do need good bike handling skills so as not to over-correct.
I set these up tubeless with Stan's no-tube cyclocross kit on standard rims (Mavic Front, Powertap alloy rear), and have been playing with various pressures between 20 and 40 psi. Have done one long race (107 miles) in Minnesota, and lots of training. Will be riding this in the Chino Grinder (Arizona) this weekend, the AlmonzoRoyal 162 next week, and the DK in June. Hoping the lower pressure will allow all of these to run a bit better than with tubes and higher pressure. So far so good. I'll update if I have any problems.
I've only got one ride on these but I'm super happy with them! My clement tires aren't very confident cornering, even on the road. These challenge tires transition real well in corners and lock up nicely on gravel. Reasonably fast on road or dry hardpack as well. Corner well in gravel.
I mounted them on a pretty narrow pair of road rims (vuelta) and my micrometer says they're more like 32's on these rims.