Krumbein
The compound engineered for dependable grip and off-road adventures.
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Casing protection and secure hold for rough terrain.
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Ultimate construction of speed, comfort and flat protection. Tubeless compatible tires feature an airtight casing and bead designed for easy mounting on tubeless rims. We recommend tubeless tape and 45-60 ml of sealant for road and gravel applications.
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Krumbein
The Krumbein is American Classic's most aggressive gravel tire ideal for gravel roads, loose trails, and fast singletrack. The all-weather design includes tall side lugs for cornering grip on loose and rocky conditions, chamfered center knobs minimize rolling resistance, and there is plenty of space between knobs to prevent mud build-up. Combined with our signature Rubberforce G tread compounds and Stage 5S Armor construction, this tire provides impressive grip in the dirt and improves both ride quality and abrasion resistance compared to its predecessor.
Features
- Fast and efficient tire from loose gravel to single track
- 700x40C, 700x50C, 650Bx47
- Tubeless Ready
- Stage 5S Armor construction
- Rubberforce G gravel tire compound
- Chamfered center tread minimizes rolling resistance
- Black, tan, or brown sidewall
| Type | Gravel |
| Compound | RUBBERFORCE G |
| Protection | Stage 5S Armor |
| Color Options | Black Tan Brown |
| Rim Fitment | Tubeless |
| TPI | 120 |
| Bead | Folding |
| Size Options | 700x40C (ETRTO 40-622) Weight: 540-545 g Max Pressure: 55 PSI (TC/TT) 700x50C (ETRTO 50-622) Weight: 670-680 g Max Pressure: 50 PSI (TC/TT) 650Bx47mm (ETRTO 47-584) Weight: 625-630 g Max Pressure: 50 PSI (TC/TT) |
2-Year Warranty
American Classic tires have a 2-year warranty against defects in materials and workmanship. Any defective tires will be replaced at no charge. This warranty applies to the original owner with proof of purchase and is non-transferable and non-assignable. The original owner is responsible for all postage costs and transportation risks of the returned product(s). The warranty covers American Classic products purchased through authorized dealers, www.amclassic.com, or the American Classic branded Amazon store, and product included as original equipment components of a new bicycle purchase. The warranty does not cover normal wear and tear, product abuse, commercial usage, shipping damage, improper installation and/or maintenance, negligence, reckless handling, and/or unauthorized modification.
Please contact support@amclassic.com for warranty information and claim forms.
Hookless Compatibility
Some American Classic tires are compatible with hookless (Tubeless Straight-Side/TSS) rims. To be compatible, the following must be met:
- The tire must be a Tubeless-Ready model,
- The tire must not include Stage 3 Flat Protection or Stage 3S Flat Protection,
- The tire must be placed on an appropriate width rim,
- The rim must meet current E.T.R.T.O. standards for tubeless systems, and
- The air pressure must be below the lowest maximum pressure as listed by both the rim and the ISO recommended pressure for Tubeless-Ready tires on hookless rims.
More information on hookless compatibility can be found on our Tire and Rim Compatibility page.
Not approved for use on hookless rims:
- Lamplighter (all versions)
- Timekeeper Tube-Type (all versions)
- Timekeeper TLR with Stage 3 Flat Protection
- Torchbearer Tube-Type (all versions)
- Torchbearer TLR with Stage 3S Flat Protection
- Any, and all, tube-type tires
Warning: the maximum air pressure listed on American Classic tires is for hook bead systems. Hookless systems require a lower maximum pressure. ISO provided maximum air pressures for hookless systems can be found in the Tire Pressure section on our Tire Basics page.
ISO - International Organization of Standards
E.T.R.T.O. - The European Tire and Rim Technical Organization