Why measuring matters
Most fitment failures come from a quarter-inch mismatch on the axle hole, not the wheel diameter. The wheel itself looks identical at 4-7/8" vs 5", but the axle hole between 5/16" and 1/2" is the part that actually decides whether the wheel rolls or sits in the parts bin. Five minutes with a tape measure or caliper saves a return.
What you need
- A tape measure or, ideally, a digital caliper
- The broken wheel (or a clean wheel from the same cart)
- The cart itself, in case you need to look at the axle
- Phone for a quick photo if you want our team to verify
Step 1: Measure wheel diameter
Lay the wheel flat. Measure across the face from one outside edge to the other, through the center of the axle. Most US grocery carts are 5 inches. Smaller express carts are sometimes 4 inches.
Step 2: Measure axle hole
Look at the hole through the center hub. Measure the diameter of the hole itself, not the hub. Standard US grocery is 5/16 inch. Some specialty carts and a few European-import cart frames use 1/2 inch.
Step 3: Measure tread width
Tread width is the thickness of the wheel — measured across the running surface from the inside face to the outside face. Most are 1-1/4 inches. A few wider carts use 1-1/2 inches.
Step 4: Identify the cart manufacturer
Look on the cart frame near the rear axle for a stamped logo or sticker. Common manufacturers in the US are Unarco, Technibilt, Versacart, and United Steel. If your store runs a national retailer fleet, the cart was likely supplied by one of these.
Step 5: Match it
With the three numbers (diameter, axle hole, tread) and the cart manufacturer, pick the matching SKU on the matching retailer hub. If you are unsure, send a photo to our fitment team via the contact page and we will confirm within minutes during business hours.
Common measuring mistakes
- Measuring an old worn wheel — wear can shave 1/8" off the diameter. If the wheel is heavily worn, measure a sibling wheel from the same cart.
- Measuring through the hub instead of the axle hole — the hub is wider; the hole inside is what matters.
- Mixing metric and imperial — most US carts are imperial. Make sure your tape is on the imperial side.
When to ask for help
If your wheel is damaged beyond measuring, or your cart is a non-standard model, send us a photo of the cart and the wheel. Our fitment team identifies the part within minutes during business hours and emails you the matching SKU with a direct order link. There is no charge.