Tyre sizing notation for forklifts can be confusing — especially when the same tyre appears under multiple size names. This guide explains how to read and cross-reference solid tyre size markings.
The Three Common Forklift Tyre Size Formats
Forklift solid tyres are marked in three main systems, all referring to the same physical dimensions but expressed differently. This causes confusion when replacing tyres or cross-referencing between brands.
- Imperial inch format: e.g. 18×7-8 (overall diameter × section width — rim diameter, all in inches)
- Metric format: e.g. 180/70-8 (section width in mm / aspect ratio % — rim diameter in inches)
- Hybrid format: e.g. 8.15-15 (section width in inches — rim diameter in inches, no overall diameter)
Reading the Imperial Format: 18×7-8
This is the most common format used in Asian markets and the format used by most Chinese manufacturers. Breaking it down: A real-world example of the imperial system at work is the 18x7-8 wide solid tyre, where the extra "wide" designation changes the tread section but not the rim.
- 18 = overall tyre diameter in inches (the full outside diameter when mounted)
- 7 = section width in inches (the widest point of the tyre cross-section)
- 8 = rim diameter in inches (the wheel diameter the tyre mounts onto)
Reading the Metric Format: 180/70-8
The metric format is common on European and some American machines. Breaking it down: The same logic applies to sizes like the 200/50-10 forklift tyre — millimetres for width, a percentage for sidewall height, inches for the rim.
- 180 = section width in millimetres
- 70 = aspect ratio — section height as a percentage of section width (180 × 70% = 126 mm section height)
- 8 = rim diameter in inches
Common Size Cross-References
The following pairs are direct equivalents — the same tyre sold under two different name conventions: Cross-references matter when a supplier quotes a different notation — our 6.50-10 solid tyre cross-reference page shows how the metric and imperial names of one size relate.
- 18×7-8 = 180/70-8
- 21×8-9 = 200/75-9
- 23×9-10 = 225/75-10
- 27×10-12 = 250/75-12
- 23×10-12 = 250/60-12
- 28×9-15 = 8.15-15 = 225/70-15
- 23×12-12 = 315/45-12
How to Find the Size on Your Existing Tyre
The tyre size is always moulded into the sidewall rubber. Look for a series of numbers on the flat face or angled sidewall. The size is typically followed by the word "SOLID" or "RESILIENT" and may include a load index and speed symbol.
If the sidewall is too worn to read, check the forklift's data plate (usually mounted near the operator seat or on the counterweight) which lists the tyre specification. Alternatively, measure the tyre: overall diameter, section width, and rim diameter — then cross-reference using the table above.
Have questions about your specific application?
Frequently Asked Questions
How do I read a forklift tyre size?
Two formats are used. Metric-style reads as section width-rim diameter, for example 7.00-12. Imperial-style reads as overall diameter × section width-rim diameter, for example 23×10-12. Both describe the same three things: width, diameter and the rim they fit.
Where are the markings on a forklift tyre?
Moulded into the sidewall, usually as the largest number on the tyre. On a worn tyre they can be faint — clean the sidewall and read in good light, or measure the tyre directly if the marking is illegible.
What does the X mean in a size like 18×7-8?
The × separates the two dimensions of an imperial size: 18 inches overall diameter and 7 inches section width. The following number is the rim diameter, so 18×7-8 fits an 8 inch rim.
How do I measure a tyre if the size is worn off?
Measure across the tyre for overall diameter, across the tread for section width, and measure the rim for the rim diameter. Then match the three numbers against the size chart for that tyre family.
Is a rim diameter the same as a wheel diameter?
For this purpose yes — the rim diameter is the bead seat diameter the tyre mounts on, which is the number after the dash or final × in the tyre size. It is the dimension that most often causes a returned tyre if it is misread.