Bike Perfect Verdict
Heavy but once up to speed they roll reasonably well and offer a very predictable grip on a range of surfaces. What they lack in souplesse they more than make up for in toughness
Pros
- +
Predictable tread
- +
Reasonable rolling speed
- +
Resilient against punctures
- +
Low cost
Cons
- -
Heavy
- -
Wallows at low pressures
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American Classic is a name you probably recognize, however in the past it was for its selection of performance MTB and road wheels. After a small hiatus the brand has respawned, launching a range of direct-to-consumer tires sold through Amazon that promise performance to compete with the best gravel bike tires at an affordable price.
The American Classic Krumbein sits at the rugged end of the line-up, aimed at tackling everything from well-graded gravel to those trails you regret taking a gravel bike down. We have been racking up the miles on our test set of Krumbeins to find out if these budget gravel tires have undercut performance.
Construction
American Classic offers the Krumbein in three sizes, a 40mm and 50mm in a 700c size and the classic 47mm in 650b. We fitted our 50mm test tires to a set of Hunt 35 Carbon Gravel X-Wide wheels with a 23mm inner diameter and the tire came up a little smaller than the stated 50mm, although this very much depends on how you measure them. It did mean there was a stark contrast in size between the Krumbein and the Schwalbe G-One Ultrabites which measure significantly larger shoulder to shoulder.
The tread pattern uses shallow chamfered one, two, three-block configuration along the center of the tire for better rolling speeds whilst the shoulders are a bit more pronounced for enhanced cornering and off-camber riding. There is horizontal siping in the center section to add another edge of grip when accelerating and stopping, whilst the shoulders feature alternating horizontal and vertical siping to allow the tread to deform more when cornering.
The 120tpi casing is the foundation for American Classic’s abrasion and cut-resistant RubberForce G compound and Stage 5S Flat Protection. The Krumbein tires have a folding bead and are hookless compatible as well.
Performance
Grip is very predictable and there was really great communication between tire and steering input so I never felt that I was pushing the tire into unchartered grip territory. Even though the large tread blocks are fairly low profile they hold lines and direction well and I felt confident pushing them into corners on both greasy mud and smooth tarmac alike. When they do break free, it isn’t a massive surprise either meaning you can make the required adjustments to stop any unplanned lie-downs. On muddy sections, the tread did a decent job of shedding sticky dirt, too.
It’s the tread pattern that is mostly responsible for the grip as it’s not possible to run these tires as soft as you might other gravel tires which form a ground molding footprint. The stiffness of the sidewalls means the tire doesn’t work all that well at low pressures and when run below 25psi, there is a distinctive wallow and vagueness when cornering. That means you also don’t get the buttery suppleness on high vibration surfaces that I have enjoyed from other high-volume tires such Schwalbes G-Ones or Continental Terra Trails. Instead corrugated surfaces and sharp edges are translated quite clearly to the rider.
While all this added puncture protection should assure you don’t need to stop at the side of the track - both tires have staved off every rock attack during 1,250km of testing - the weight definitely means it’s harder to get up to speed. At almost 750g per tire, they are verging on MTB weight levels without the benefit of the extra volume along with it. Considering many 50mm tires come under 600g each, it’s quite a bit of added weight so they wouldn’t be my first choice for go-fast scenarios unless reliability was an important consideration too.
They do roll pretty quickly though and when run at around 30psi they can carry speed well for a large tire meaning they could be a good option for bikepacking where weight isn’t as much of a consideration, and durability certainly is.
Fitting was fuss-free with no need to use a pressurized blast or resort to over-inflation. They have held their air reasonably well too, needing a top-up every now and then as is expected. Longevity seems to be pretty decent as well after a good chunk of mileage. Even better is the fact that American Classic offers a Road Hazard Replacement Policy on top of its two-year warranty. So if you damage your tire to the point that it no longer holds air, American Classic will offer a like-for-like replacement for half price.
Verdict
The Krumbein tires aren’t the most comfortable and are definitely on the heavier side, yet they roll reasonably fast and have been very reliable in both grip and keeping punctures at bay.
They aren’t going to feel as buttery smooth as other lighter and thinner-walled 50mm gravel tires on the market, however, very keen pricing means these are a dependably rugged tire for $35 that are ready to take a battering.
Tech Specs: American Classic Krumbein
- Price: $35 / £N/A
- Weight: 737g (averaged from two 700 x 50mm tires)
- Colors: Black or tan
- Sizes: 700 x 50mm (tested) and 40mm, 650b x 47mm
