Tire Flotation and Load Capacity over Sand/Soil

Wagons with large footprint air tires expand their usefulness over soft terrain. The following table represents suggested maximum loading per tire for adult hand-pulled wagons and trailers over a level surface. The table does not assume that the tire loading times the number of tires is the total safe maximum for the combination of wagon, load, terrain and person on the handle; that will vary by person pulling and variations in the terrain. Please review the notes below the table for further information. Wagon on sand experience was gathered at North Carolina's treasured Cape Lookout National Seashore.

A few notes:

*An up slope of 15 degrees will add more than 25% of the rolling weight to the drawbar force.

*The tire sizes listed are common nominal rounded number sizes, for example the 10" x 4" tire is actually 3.6" wide; the same tire could be described either way. 

*For machine-pulled full-frame wagons, the pulling force can be very high though the tire is still able to carry the maximum weight listed on the sidewall at the max inflation pressure. Reducing the inflation pressure increases the pulling effort primarily on hard surfaces while lowering capacity.

*A tire pressure of less than half the rated max is not recommended especially for tubeless tires which seal at the bead.

*Both the tread pattern and tire pressure seems irrelevant to the effort of rolling unpowered tires in soft sand.

*Most small tires are "A" speed rated for 20 mph max.

Air Tire Issues

Any air-tire item will need a tire pump at intervals of several seasons. Below are useful hints.  Check the page titled “Part Sources, Manuals Warranty Information Contacts” for sources of replacement tires and tubes.

Difficult Air Tire Valve Access

If your pump nozzle end is too big or too short to properly fill an air tire, solutions are available. Some toy wheel rims with trim covers may be made more accessible by taking apart enough of the axle to pull away the cover, exposing more stem length. A handy solution is also a valve stem extension which replaces the cap. They are usually sold in sets of four to allow filling tires on cars with access to the too short valve stem reduced by full wheel covers. Look in a hardware or auto parts store for a card with four pencil diameter black cylinders about 1.3" long. Leave it on the wheel if it is not interfering or subject to damage with use, or keep one with your pump.

Flat Tires

Flat tires from punctures are very rare especially where the tire loading is only a small fraction of its capacity. A common issue for small tubeless tires is a break in the tire to rim bead seal covered below. A new wheel/tire assembly purchase may be simpler especially if the rim is rusted, but be sure to obtain a new axle retainer if used. Most flats can be repaired without any disassembly only prying the tire half way (one side) off the rim. Tires may have have an inner tube or have a sealed rim and a tire that is coated to stop leaking- a tubeless tire. It is an option to add an inner tube where it was previously a tubeless tire.

Spotter's guide: A tubeless tire will have a valve stem that is much thicker at the base than the diameter of the hole in the rim. It is set tightly as a grommet and won't be easily pushed or pulled. An inner tube's valve stem will be only slightly tapered and you will be able to see the edge of the hole in the rim.

First verify that the valve stem is tightly set and not itself the source of the pressure leak. A drop of detergent water on the valve under the cap will bubble if leaking. It can be threaded tighter with a tool that you may already have on the outside of a plastic or metal cap on some other valve stem. If no valve stem tool is available, needle nose pliers or tweezers often work as a wrench. A leak at the valve stem base on a tubeless tire means that the valve stem is bad or the seal to the wheel hole is a problem. If a tubed tire leaks at the base of the valve stem the leak can be anywhere in the tube but just exits the rim at the stem hole.

When you get a flat with a tubeless tire look for the leak by wetting the tire with dishwater. If either side rim to tire bead seal leaks, look below for a procedure. If the flat is on the tread or sidewall there are some choices. One option to fix a cut or hole in a tubeless tire is to simply put a tube in it. Only half of the tire need be pried off the rim to insert the tube. A tire pro can also patch the inside of the tire and reseat the tire on the rim.

If there is an inner tube with a leak, it can be patched or replaced by prying the tire halfway off the rim- carefully so as not to lance the tube. Patch or replace the tube, stuff it in enough to avoid pinching possibly with a little air to fill it out. In either tube or tubeless case, make sure that the tire is well centered and seated before gradually adding air up to at most the tire's maximum pressure.

Mounting A Tire On or Off A Rim

Easier said than done, especially putting a tire onto a rim; this may be too ambitious for some readers. Disclaimer: Use this information at your own risk. Beware of the hazards of finger pinches or a sudden slip of the tool, and eye hazards such as from a tire valve. CAUTION: Use of foul language could occur. Tire, valve stem (or tube) and wheel should be inspected or known to be in good condition. New valve stems are recommended with new tubeless tires, they easily insert from inside before the tire is on the rim. The only way to remove a tubeless valve stem is to cut it off from either side and take the two sides away. Rims are made to facilitate the tire installation from the front side of the rim.

To mount a tire onto a wheel, secure the wheel rim outside up and place the tire outside up on top of the front side of the rim. Lubricate the tire beads with a minimum amount of tire mounting lube or vegatable oil emulsifed in detergent water. Hook as much as possible of the back tire bead over the front rim edge by hand, about halfway around. Use a flattened hook-shaped prying shape to put more of back bead of the tire over the front edge of the rim. Hold the tire so that the back bead is in the deepest recess of the rim on the side opposite your pry bar. A second pry bar is useful to prevent the tire bead from coming back onto the front side after working hard to put in under the rim edge. Work the pry bar(s) around until the whole back bead is inside the rim while the front bead is still outside of the front of the rim.

Insert the tube, if used, at this point and spread it into its approximate place, but beware- avoid puncturing it. If present, inflate the tube just enough to give it a soft inflated shape. Then start about half of the front bead over the front edge of the rim by hand. Start prying the front bead over the front of the rim with the hook end pry iron. Continue to push the part of the front bead that is already in the wheel opposite the pry site into the deepest recess of the rim. This reduces the effort at the pry location and it is part of the tire/rim design. Once on all of the way around with both beads, seal small tubeless tires per instructions below, and larger ones with instructions from a tire maker.

To pull a tire off a wheel rim, start by letting out all of the air by unscrewing the valve body from inside the stem, catching it in a rag. With no pressure possible in the tire, break the bead adhesion to the rim on both sides. Pressure from a piece of wood or shoe heel will break the beads loose on small 4"-6" rim size tires. A purpose built bead-breaker with a long lever is usually the only solution for 13" and larger automotive tires. Once the beads are free to move away from the seating portion of the rim on both sides, secure the wheel outside up. Lubricate the tire beads with a little squirt of tire mounting lube or vegatable oil emulsifed in detergent water. Use a flat pry bar or "spoon" shaped end of a double ended tire iron tool. Pry the front of the tire from the front side of the rim all of the way around, while the back bead is in the deep part of the rim opposite the pry area. Then lift the tire so that the back bead is fully within the top part of the deepest recess of the rim, and get your pry tool under the bead from the front rim edge. Work the tool or tools sideways under the back bead up to the front edge of the rim, and rotate the tool with bead over the front edge of the rim. Work more of the back bead over the front of the rim until nearly the whole way around to free the tire completely. Tires are nearly perfect at trapping water so they should not be stored where rainwater can enter and foster insects.

Sealing Small Tubeless Tires on Toys

It is often hard to get a tire without an inner tube to seal all the way around both sides of a tire/rim bead. Tire pros have a device at the shop to blast a lot of air in all at once, and it works well. For the rest of us haplessly at home, try this- but WARNING: your pants could fall down. Jack up the tire so that it has no flattened side or loading and wet both beads with tire mounting lube, vegetable oil or water and detergent (dishwater?). Take a belt from your waist or a cargo strap or rope and put it around the circumference of the tire along the center of the tread. Pull it tight and then put the air in, it may also help to thump your fist on the tread to momentarily displace some trapped volume outward at the beads. When the bead seals be careful not to suddenly overinflate (especially a small tire) beyond the maximum pressure on the sidewall.

Again, please consider your own expertise before working with tires as Wagon Train Ventures, LLC takes no responsibility for the outcome of your attempts--or the words your listening children learn in the process!  For more difficult repairs, you may consider looking up your local lawnmower repair shop or bike shop.