Challenge have made a valiant effort with their new handmade Limus mud tire, but the burning question is: can it beat the best European tubulars? When it comes to pure performance, no. But taking other factors into account, it's a decent alternative.
It's not as quick – at the uber-muddy round 3 of the Exergy USGP of Cyclo-cross in Fort Collins, Colorado we were roughly 10 seconds slower per nine-minute lap on the Challenge tires than on our benchmark Dugast Rhinos with their super-supple cotton casings.
However, while at the top level of the sport that sort of advantage can mean UCI points, victories and team contracts, for the layman it comes at a significant cost. The Limus tires are cheaper, at a suggested US$200 a pair, don't require additional sealing to their sidewalls (avoiding further expense), and their poly-blend casings are less susceptible to rot.
The size of the knobs, and durometer of the rubber, keep the Limus from being too squirmy on hardpack and pavement
Overall, Challenge have done plenty right with the 300tpi Limus and they've come out with a solid tire. While the tread looks extremely aggressive, its wide, slightly chamfered knobs (ie. the base is wider than the tip) actually have less bite in mud than the narrower, straight-sided knobs used by some of Challenge's competitors.
What the Limus loses in terms of no-holds-barred mud performance, however, it gains in terms of reduced squirm on hard surfaces and pavement, making it much more versatile and capable of dry condition use. The large knobs do give it a fairly rough, slow-feeling ride and a little bit of buzz on the road, though, so we'd reserve it for courses needing a really aggressive, almost mountain-bike-like tire.
The big knobs leave the Limus feeling slightly sluggish
Contributing to this rough ride is the synthetic casing, which isn't nearly as supple as the best cotton casings, both in terms of cushiness for comfort and the ability to conform to and grip the ground – the ultimate performance attribute for a cyclo-cross tire. The amount of rubber used in the tread adds to the stiff feel and helps explain the tire's weight – our samples were 413g and 452g.
Even at very low pressures – 22psi in the front and 24psi in the rear – the Limus resisted folding out from under our wheels; the extra-wide Zipp 303 tubular rims they were glued to undoubtably played a part in this. The tires easily passed the UCI's go-no-go test for tire width, measuring just shy of 32mm with our calipers.
The Limus is cold vulcanized – ie. hand glued – and uses a latex tube made in-house. Challenge have struggled with quality control over the years but our tires came well put together, with good attention to detail in terms of straightness and good glue adhesion for both the tread and base tape. Even after a solid 'mudder' with ample power washing they've yet to show any signs of degradation.
The construction of our test tires was very good