I have to say that I absolutely love the way these tires ride on both dirt and and tarmac but I do not know if I would ever buy them again. We have had a very wet January/February and I have done a lot of miles in the wet on these tires. I have done 1200 miles on them since installation and suffered five flats. I have had more flats on these tires than I have had in the past 5 years. On the other hand I have ridden in the rain more than I have since moving to California.
Bike Tires direct have this to say about the tires:
“While many of Challenge’s previous tires are right at home on gravel, they wanted this one to be specially tailored for longer, more demanding rides where tire width and flat protection are at a premium. To this end, they gave the Gravel Grinder Race their Double Puncture Protection System (PPS2) and spec’ed it with a generous 38mm width, resulting in great durability and dependability with comfort and stability on uneven and loose terrain. With file tread in the center, the Gravel Grinder roles smoothly, but still grips turns thanks to its more aggressive shoulder knobs.”
I am afraid I see no evidence of an effective double puncture protection system. I think the tread wear on the back tire after 1200 miles is pretty significant.
Tread wear after 1200 mostly road miles.