American Classic Krumbein gravel tyre review

American Classic launched in 1982, manufacturing wheels, hubs and seat posts. Although it closed down in 2018, the brand relaunched in 2021 with a whole new range of tyres. 

Across the models, the design is geared towards maximum performance at minimum cost – they’re not trying to compete directly with the very best tyres on the market, instead going for functional affordability.

For a complete overview of all the tyres in the range (there are a lot!), you can check out our launch story over here. Otherwise, let’s dig into the Krumbeins

The construction: American Classic Krumbein

The Krumbeins feature the Rubberforce G compound which was designed specifically for American Classic’s gravel range. It's said to provide “excellent abrasion resistance, high tensile strength, and good tear and cut resistance for off-road riding and exploring.”

It’s paired with “Stage 5S Flat Protection”, providing bead-to-bead puncture and tear protection, courtesy of a “microfibre composite tread compound and undertread protective layer.”

The tread itself consists of smaller blocky knobs down the centre of the tyre, to minimise the penalty on rolling speed, with a transition out to larger and taller knobs on the shoulders, for added grip when banked over in the corners.

Naturally, for a gravel tyre, it’s tubeless ready and compatible with hookless (straight sided rims). There is a ‘tan’ sidewall option, but this is purely aesthetic – rather than the carcass actually being left bare to increase the suppleness. There are only available in three sizes, 40mm x 700c, 50mm x 700c, and 47mm x 650b.

Unusually for a tyre brand – it's more common for wheels – if you manage to damage the Krumbeins to the point that they can no longer hold air, American Classic will give you 50% off the MSRP of a new one to get you rolling again.

The ride

Popping the tyres on my scales before setting them up, their heft was quickly confirmed. The 50mm x 700c version came in at 752 grams, which is 17 grams over the claimed weight and notably heavy for a gravel tyre.

For context, Schwalbe’s G-One Ultrabite tyres – similarly burly and arguably more aggressively treaded – have a claimed weight of 665 grams in 50mm x 700c. The comparison with MTB tyres is even less favourable, Schwalbe’s Rocket Ron XC tyres have a claimed weight of 595 grams in 54mm x 700c. 

Then again, the Krumbeins are significantly cheaper than either of those tyres. When you’re balancing weight, protection and price, one of those is always going to be sacrificed.

Getting them inflated on a set of wheels went largely without issue. They were a little stiffer than some to get mounted on the rim and required a few more blasts with an air-chamber track pump to seal the bead against the rim. 

That said, it still wasn't a struggle, with the experience about par for the course when it comes to gravel tyres.

The Krumbeins have definite strengths and weaknesses. Even top end tyres don’t tend to be flawless – going cheaper only increases the scope for compromises. At this price point, it will always be a balance of which areas of performance are you willing to give up.

Of the good points, the puncture protection performed well when set up with sealant, never losing a significant amount of pressure when out on a ride. Equally the sidewalls stood up well against unkind, rocky descents.

I've used these tyres with Tubolito’s City/Tour inner tubes and did get a flat – which reflects pretty unfavourably on both. The tubes are supposed to be unpuncturable, but if the tyre's puncture protection was perfect, then it wouldn’t have happened anyway. All that said, when set up with even basic sealant, I never had a problem.

Writing this review in February, thoughts of dry and dusty trails feel quite a distant notion. However when riding in the tail-end of the summer, I found the size and shapes of the knobs provided a respectable amount of grip over small, shingle-y rocks and finer dust. Of course they don’t work miracles – deep patches are always unpredictable, providing ample grip right up until they don’t – but generally they were good.

On tarmac sections on the way to the trails, the rolling resistance doesn’t feel a massive drag. I’d be frustrated if I was racing – performance mountain bike tyres turn over faster than the Krumbeins – but for general riding they passed the bar. Although maximum speed isn't always a priority, it’s never fun feeling like you’re riding through treacle.

Now, to the downsides. My main complaint is regarding the tackiness of the compound. Or lack of it. On wet rocks, it’s not the tread that provides the grip, but the rubber itself. Other gravel tyres, such as the Schwalbe Ultrabites, have a pretty tacky compound that grips well in wet, rocky conditions. The Krumbeins, on the other hand, felt rather skittish and slippery, limiting how fast I could take the corners.

The other point is more an observation than a criticism. Although the tread is more aggressive than many gravel tyres out there, the knobs still aren’t tall or widely spaced enough to work well in the mud. They neither dig in deeply enough or shed the clag quickly enough. In short, if you’re after a gravel tyre that can handle the winter slop, the Krumbein isn't it.

Value

At $35.00 dollars per tyre, American Classic’s Krumbeins are notably cheap. Although Schwalbe’s aggressive G-One Ultrabite gravel tyre really impressed us – being light and having better grip on wet surfaces – it comes in at $62.00 a tyre. The Teravail Rutland, in its 47mm x 700c width and with its ‘durable’ casing, comes in at $65 per tyre.

Verdict

American Classic’s Krumbein tyres are a particularly cheap option for a high volume and more aggressive gravel tyre. They do have their drawbacks, being rather heavy and using a compound that isn’t super tacky in the wet. But they are also impressively robust, grippy in the dry and have a reasonable rolling speed. 

If you baulk at the thought of paying over $60 for a bike tyre, you’re unlikely to be disappointed – just don’t expect them to be quite as fast, light or grippy as rubber almost twice the price.

Specs

• Weight: 752g
• Sizes: 40mm x 700c, 50mm x 700c, 47mm x 650b
• Sidewalls; Black, Tan
• Contact: www.amclassic.com

FAQs