A 4.00-6 tire is a pneumatic wheelbarrow tire 4 inches wide for a 6-inch rim, with a 9.4-inch outer diameter and 300-500 lb capacity.
The designation 4.00-6 on a wheelbarrow tire tells you two things: the tire is 4 inches wide and it fits a 6-inch diameter rim. Together these numbers describe the standard replacement tire for most residential wheelbarrows, garden carts, and small utility trailers. If the sidewall reads 4.00-6, you have a match for the vast majority of homeowner-grade equipment sold in the US — and knowing the full specs helps you pick the right ply rating, avoid sizing mistakes, and keep the load within safe limits.
What Do the Numbers 4.00-6 Mean?
The 4.00-6 size breaks into two measurements. The “4.00” refers to the tire’s section width — approximately 4 inches across the tread — while the “6” indicates the rim diameter in inches. The overall outer diameter of the tire itself is about 9.4 inches, though the full wheel assembly (tire mounted on a 6-inch rim) is commonly cited as a 13-inch wheel. This two-number format is standard for small pneumatic tires used on equipment that sees slow, heavy loads rather than high-speed road travel.
The 4.00-6 size is also written as 400X6 or 4.00×6 on some packaging and sidewalls. All three notations mean the same thing: a 4-inch-wide tire for a 6-inch rim.
Full Specifications for the 4.00-6 Tire Size
Knowing the exact specs helps you compare models and avoid grabbing a mismatched replacement.
| Specification | Standard Value | Notes |
|---|---|---|
| Section Width | 4.2 inches | Ranges from 3.7 to 4.0 inches across brands |
| Outer Diameter (tire only) | 9.4 inches | Wheel assembly is roughly 13 inches overall |
| Rim Diameter | 6 inches | Must match exactly — an 8-inch rim will not fit |
| Ply Rating | 2-Ply or 4-Ply | Higher ply means heavier load capacity |
| Load Capacity | 300–500 lbs | 2-ply: 300 lbs; 4-ply: up to 500 lbs |
| Inflation Pressure | 30 PSI | Over-inflation risks blowout; under-inflation reduces load capacity |
| Tire Type | Tubeless (most common) | Some variants require an inner tube — check the sidewall stamp |
| Tread Pattern | Rib | Designed for firm, dry surfaces; not ideal for deep mud |
Common 4.00-6 Tire Models and Prices
Several manufacturers produce 4.00-6 tires with slightly different build specs. The Marathon P120 is a widely available 2-ply option rated at 300 lbs and priced around $18–$24. If you are comparing your options, our roundup of the best 4 00 6 tire and tube and wheel covers tested models with fit notes and price comparisons.
How to Verify a 4.00-6 Tire Fits Your Rim
Before buying, confirm the match with four quick checks. First, read the sidewall — if it says 4.00-6, it is the right width-to-rim ratio. Second, measure the actual rim diameter across the bead seat; it should be 6 inches. Third, check whether the tire is stamped “Tubeless” or “Tube Type” — this tells you whether you need an inner tube. Fourth, deflate the old tire completely and inspect the valve stem: if it stays in the hole when deflated, the rim is set up for tubeless tires; if it falls inside, the wheel requires a tube. Most 4.00-6 tires sold today are tubeless, but always verify before mounting.
Common Mistakes with 4.00-6 Tires
The most frequent error is confusing tire outer diameter with overall wheel diameter. A 4.00-6 tire measures 9.4 inches across when unmounted, but on a 6-inch rim the whole assembly is about 13 inches tall — and some retailers list only the 13-inch figure, causing buyers to think they need a different size. Another common mix-up is assuming the 4.00-6 takes an 8-inch rim because the number looks similar to 4.80/4.00-8 tires, which fit 8-inch rims. Ignoring the ply rating is also risky: swapping a 2-ply tire for a 4-ply (or vice versa) changes the load capacity significantly, so replace like with like unless you are upgrading intentionally.
How Does 4.00-6 Compare to Other Tire Sizes?
Several small pneumatic tire sizes look similar but will not fit the same rim. The table below shows how 4.00-6 compares to the sizes most often confused with it.
| Tire Size | Rim Diameter | Common Use |
|---|---|---|
| 4.00-6 | 6 inches | Residential wheelbarrows, utility carts |
| 4.80/4.00-8 | 8 inches | Garden tractors, larger trailers |
| 3.50-6 | 6 inches | Light hand trucks, small garden carts |
| 5.70-8 | 8 inches | Large garden carts, log splitters |
| 16×6.50-8 | 8 inches | Lawn tractors, riding mowers |
| 5.90-6 | 6 inches | Wide wheelbarrow turf tires |
| 5.30-4.3 | 4.3 inches | Specialty lawn equipment |
The safest rule: always measure the rim you have before ordering. A 6-inch rim takes a 4.00-6, 3.50-6, or 5.90-6 tire; an 8-inch rim needs a 4.80/4.00-8, 5.70-8, or 16×6.50-8. Checking that number alone prevents nearly all fit failures.
What to Check Before You Buy a 4.00-6 Tire
Start with the ply rating. If your wheelbarrow hauls dirt, mulch, or standard garden loads, a 2-ply 4.00-6 tire rated at 300 lbs handles the job. For heavier hauls — concrete mix, stone, or dense soil — step up to a 4-ply version rated at 500 lbs to build in a safety margin. Confirm the inflation spec of 30 PSI; running lower than that cuts load capacity, and running higher risks a sidewall blowout on rough ground. Finally, decide between tubeless and tube-type: if your rim has a bonded valve stem hole, stick with tubeless; if the inside of the rim has a separate slot for a tube stem, buy a tube-type tire or add an inner tube. The right 4.00-6 tire matched to your load and rim will outlast the project you are buying it for.
FAQs
What is the difference between 4.00-6 and 4.80/4.00-8 tires?
Both tires are about 4 inches wide, but the 4.00-6 fits a 6-inch rim while the 4.80/4.00-8 fits an 8-inch rim. They are not interchangeable. The 4.80/4.00-8 also has a larger outer diameter and is typically used on garden tractors and larger utility trailers rather than standard wheelbarrows.
Can I put a tube in a 4.00-6 tubeless tire?
Yes, you can add an inner tube to a tubeless 4.00-6 tire as long as the rim is compatible. The valve stem on a tubeless rim stays fixed in place, while a tube-type rim allows the stem to fall inside when deflated. Adding a tube is a common fix for a slow leak in a tubeless tire.
What PSI should I use for a 4.00-6 tire?
The standard inflation pressure is 30 PSI for most 4.00-6 tires regardless of ply rating. Exceeding 30 PSI increases the risk of a sidewall blowout under load, while under-inflating reduces the rated load capacity and causes uneven tread wear. Always check the sidewall marking for the exact recommended pressure.
Will a 4.00-6 tire fit any wheelbarrow?
It fits the vast majority of residential wheelbarrows sold in the US, but some heavy-duty contractor models use a 4.80/4.00-8 or 5.70-8 tire on an 8-inch rim. Older or lightweight wheelbarrows sometimes use a 3.50-6 tire on a 6-inch rim. Always measure the rim diameter before purchasing — 4.00-6 only fits a 6-inch rim.
How long does a 4.00-6 tire last?
Lifespan depends on load, terrain, and inflation maintenance. Under normal residential use with consistent 30 PSI inflation, a 2-ply tire lasts 2–4 years before dry rot or tread wear sets in. A 4-ply tire running at the same pressure typically lasts longer because the heavier carcass resists cuts and sidewall cracking better.
References & Sources
- Marathon Industries. “4.00-6 Pneumatic Tire P120 Product Page.” Manufacturer specs for a common 2-ply 4.00-6 wheelbarrow tire.
- Home Depot. “HI-RUN CT1006 4.00-6 Tire Product Page.” Retail listing with 4-ply specs, load rating, and pricing.
- Grainger. “HI-RUN Wheelbarrow Tire 4.00-6 Specs.” Detailed industrial spec sheet for 4.00-6 tire measurements.
- Shepherd Hardware. “4.00×6 Wheelbarrow Replacement Tire.” Manufacturer listing for 500-lb capacity variant with rib tread.