Solid tires can cut flat repairs on a cargo bike. They can also fail early if the rim, load rating, or width doesn't match. Measure first, buy second.
The work is in the details. Here's how to work through it without guesswork.
Measure the rim before you shop
Start at the rim, not the product photo. Tannus Airless support tells you to find the ETRTO measurement on the rim sticker, like 622-15C, where the 15 is the internal channel width in millimeters. No sticker? Remove the tire and measure the inside channel with a caliper or ruler. This is the number that decides whether an airless tire can sit safely.
Airless tires from Tannus fit clincher rims. They do not fit tubular or hookless rims, according to Tannus Airless support. That single check rules out a lot of incompatible wheels. If you ignore it, the tire may mount but not lock correctly.
Then confirm the tire size on the sidewall. A cargo bike often uses a 20-inch wheel for stability and maneuverability, per a Ferla Family Bikes wheel size guide, but that's not universal. Your bike may use 26-inch wheels, or a mix. Write down the exact size, such as 20 x 2.4, and compare it with the solid tire listing.
Here's a simple order:
- Read the rim ETRTO and tire sidewall.
- Measure the rim's internal channel if you can't find a sticker.
- Match both numbers to the tire maker's size chart.
- Check frame, fender, and brake clearance before buying.
A tire that's 5mm too wide can rub a chainstay under load. That's not a tire defect. It's a fit problem.
Pick Airless or Armour for the right job
Tannus sells two different answers. Tannus Airless is a foam tire with no air and no tube, secured with a proprietary Locking Pin System on compatible rims, as described in the Tannus America flat protection guide. Tannus Armour is an insert that sits between the tire and the tube. It is not a solid tire.
Armour adds 13-15mm of protection at its thickest point and 2-5mm at the sidewall, with weights from 190g to 500g depending on size, according to Tannus Armour support. Because the tube remains, you can still tune pressure. Tannus says the insert can let you run lower pressure for comfort and control.
Airless changes the ride more. Tannus notes that most riders don't feel a difference, but some notice a speed decrease of 5-10%. That matters for a delivery route with tight timing. It matters less for a short urban loop where flat repairs cost more than a slight speed loss.
Pick Airless if you want to remove tubes and flats, and your rims are compatible. Pick Armour if you want puncture resistance while keeping standard rims, tubes, and pressure tuning. Neither is automatically better. The rim and load decide more than the marketing.
Match load rating to the loaded axle
Thing is, a cargo bike's payload number is not the same as the load on each tire. Put a 180-pound rider on the saddle, add a battery, a rack, and cargo, and the rear tire may carry far more than half the total. Solid tires and inserts must support that loaded axle weight, not just the bike's brochure number.
Tires carry a load rating. Rims and frames have limits too. Find the lowest limit in the chain and stay under it. An axle load calculator can help you estimate how weight shifts, but the bike maker's maximum load and the tire maker's rating are the final authority. If the numbers are close, leave margin for potholes, curb drops, and emergency braking.
Cargo bike safety standards such as EN 17860:2024 cover vehicle design and testing for cargo bikes, including heavy models, as outlined by ACT Lab. They do not prove that a specific solid tire fits your specific rim. Treat vehicle certification and tire compatibility as separate checks.
Compatibility checks that stop bad installs
A solid tire or insert can look right and still be wrong. Run these checks before you mount anything.
- Rim type: Tannus Airless needs a clincher rim, not tubular or hookless.
- Internal channel: the rim's ETRTO width must match the Airless size requirement.
- Pin size: as a general rule, Tannus says the pin should be 3.5mm wider than the rim width, per Tannus America Airless support.
- Tire width: check frame, fender, and brake clearance at full compression.
- Load: confirm the tire or insert rating covers your loaded axle weight.
- Installation support: Tannus recommends an authorized dealer for Airless installation.
If a seller can't confirm these points for your exact bike, don't buy yet. A cheap tire that detaches under load is not a bargain.
Install and test in stages
Installation steps vary by model and rim. Use the maker's manual, not a generic video.
- For Tannus Airless, confirm the correct pin size and seating method. Have a dealer install it if you're unsure.
- Check that all pins are fully engaged. If a pin shows after installation, stop and correct it.
- For Tannus Armour, mount the insert and tube, then inflate within the tire sidewall limits and your bike maker's pressure range.
- Ride unloaded first. Listen for rubbing and feel for wobble.
- Add cargo in stages and re-check pressure, clearance, and pin seating.
Do not apply air-pressure advice to Tannus Airless. It has no air chamber. Pressure guidance belongs to Armour or to a standard pneumatic tire, not to a foam airless tire.
For Armour, pressure is a personal preference within safe limits. Heavier loads usually need more pressure to protect the rim and reduce sidewall flex. Too much pressure can make the ride harsh and reduce grip. Too little can let the tire squirm or pinch. Start with the bike maker's recommendation, then adjust in small steps.
Lifespan, fleet testing, and when to replace
Tannus claims up to 9,000 km of service life in Japan cargo bike use, according to a Tannus cargo bike report. Treat that as a maker claim, not a guarantee. Real life depends on load, terrain, speed, heat, and how often the bike stops and starts. A heavy four-wheel cargo bike on rough streets will not match a light two-wheeler on smooth pavement.
For a fleet, test one bike before rolling out a full change. Track flat frequency, installation time, rider complaints, range, and wear. Check the tread, sidewalls, and pin area during normal service. Replace anything that shows cracks, loose seating, or uneven wear.
Turns out the biggest fleet cost isn't always the tire. It's the downtime. If a solid setup prevents two roadside repairs a month, the speed loss may be acceptable. If riders complain about vibration on long routes, Armour with pressure tuning may be the better compromise. To be honest, the only way to know is a controlled test on your own routes.
FAQ
Do solid tires need tire pressure?
Tannus Airless does not use air pressure. Tannus Armour uses a tube, so it does need pressure. Set it within the tire sidewall limit and the bike maker's range, then adjust for load and comfort.
Can I install Tannus Airless on hookless rims?
No. Tannus Airless support says the tires fit clincher rims, not tubular or hookless rims. Check the rim sticker or measure the internal channel before buying.
What load rating do I need for a cargo bike solid tire?
Match the tire or insert rating to the loaded axle weight, not just the bike's total payload. Use the tire maker's rating, the rim limit, and the bike maker's maximum load. Keep margin for rough roads and heavy braking.
How long do cargo bike solid tires last?
Tannus claims up to 9,000 km in Japan cargo bike use. Actual lifespan varies by model, load, terrain, and maintenance. Inspect regularly and replace at the first sign of cracking, loose pins, or uneven wear.
Are solid tires allowed on e-cargo bikes?
Local rules vary by country, state, and city. Tire and rim compatibility is a separate question from vehicle type approval. Check your local e-bike rules and the bike maker's manual before changing wheel equipment.
