When pneumatic tires are gone, wrap a split garden hose round the rim, wind rope tightly in a spiral and coat it with pine pitch or tar, or bolt or wire strips cut from vehicle tires to the rim; each works but rides rough and drags much more. At 4 m/s a 90 kg rider on air tires uses about 17.7 W to roll, while an assumed solid-tire coefficient of 0.025 takes about 88.3 W, most of the 75-100 W a person can pedal comfortably.
Part of Bicycle Repair & Fabrication
Tire alternatives are non-pneumatic coverings, made from hose, rope, salvaged rubber or wood, fitted to a bicycle rim when air tires and tubes are unavailable.
What Rolling Costs
The power to overcome rolling resistance is the coefficient times the weight times the speed. For a rider and bicycle of 90 kg (883 N) at 4 m/s (14.4 km/h), ignoring air drag, which is small at this speed:
| Tire | Coefficient (assumed) | Force | Power |
|---|---|---|---|
| Good pneumatic | 0.005 | 0.005 × 883 = 4.4 N | 4.4 × 4 = 17.7 W |
| Hose or rope wrap | 0.02 | 17.7 N | 70.6 W |
| Solid rubber strip | 0.025 | 22.1 N | 88.3 W |
The coefficients are assumed orders of magnitude, not measurements: a pneumatic value of about 0.005 is a recalled figure for a good air tire on smooth hard ground, and the improvised values are guesses at a hard, non-flexing tire. The parent article gives 75-100 W as what a person pedalling comfortably produces (Bicycle Repair & Fabrication), so a solid tire at 4 m/s consumes most of a rider’s comfortable output. Expect to travel slowly, and plan the load and the route accordingly.
The Options
- Garden hose tire: split a garden hose lengthwise and wrap it round the rim, secured with wire or zip ties. Rough ride, but functional. Loop the ties round the rim between the spokes so they do not wear through where they cross the road surface.
- Rope wrap: wind rope tightly round the rim in a continuous spiral and coat it with pine pitch or tar for durability (Pitch Making, Tar Properties).
- Solid rubber: cut strips from vehicle tires, which are abundant in salvage, and bolt or wire them to the rim. Heavy but nearly indestructible.
- Wooden rim: in extreme cases, a thick wooden rim with a leather or rubber strip as the contact surface. This is essentially reinventing the carriage wheel; see Basic Wheel Construction.
What You Need
- Hose, rope, tire strips, or wood, in lengths to cover the rim circumference (about 2 m for a 700C wheel)
- Wire, zip ties, or bolts
- Pine pitch or tar, for rope
- Cutting tools: knife, snips, drill
- Pliers and a file to dress fastener ends
Method: Fit A Non-Pneumatic Tire
Step 1: Remove the old tire, tube and rim tape.
Step 2: Choose the covering from the options above.
Step 3: Wrap or fix it to the rim, with the joint where the ends meet made as smooth as possible.
Step 4: Fasten with wire, ties or bolts. Cut off and bend over every sharp end, and file bolt ends flush.
Step 5: Check clearance: the covering must clear the brake pads, the fork and the frame, and the wheel must still turn freely.
Step 6: Test slowly on flat, empty ground, and re-tighten after the first short ride.
Common Mistakes
- Rubber that covers the brake track — the pads then grip rubber that can slip or wear away.
- Sharp wire ends — they cut rider and tire.
- A joint that bumps — each turn of the wheel jolts the whole bicycle and loosens fasteners.
- Riding at normal speed — the coverings do not grip or cushion like air.
Safety
A covering that comes off, or brakes that cannot grip
A hose or rubber strip that works loose can jam in the fork or frame and stop the wheel, throwing the rider; a wet rim with rubber on it brakes poorly. Ride slowly, check the fastenings after the first stretch and every rest, and keep the covering off the rim’s braking surface. For the general principle, see Improvised Parts & Fabrication.
What’s Next
- Learn next: Cable & Brake Substitutes — keeping the brakes working
- Combine with: Flat Tire Repair — keeping air tires alive longer