When you’re looking for a 700x35c Bike Tire, you might expect it to measure exactly 35mm in width. However, the world of bike tire sizing isn’t always that straightforward. There’s a long-standing discussion in the cycling community about whether tire size markings accurately reflect the actual dimensions of a tire. This article explores the potential reasons behind this discrepancy, particularly focusing on the 700x35c tire size.
One theory suggests that the issue dates back to when tire sizes were primarily marked using imperial measurements. Inches were often rounded to the nearest eighth, even if the true size was slightly different. Manufacturers might then round up or down to these nominal sizes (like 1/8″ increments), or to convenient metric equivalents such as 25mm, 28mm, or 32mm.
This practice could lead to a tire that’s actually slightly wider or narrower than its stated size, depending on the rim width used during measurement and whether the manufacturer rounded up or down. For instance, a tire that measured just under 35mm might be rounded up and labeled as 35mm, while a slightly larger tire might also be called 35mm.
Even with the metric system now widely adopted in tire sizing, we still see remnants of this nominal sizing approach. You rarely find tire markings in odd metric sizes like 27mm or 29mm above 25mm, and similarly, sizes like 19mm or 22mm are less common than one might expect if sizes were perfectly precise.
It’s worth noting that this concept of nominal sizing isn’t unique to bike tires. Many industries use nominal dimensions, where the labeled size is a close approximation rather than an exact measurement. A common example is the standard 2×4 lumber in construction, which in reality doesn’t measure a full 2 inches by 4 inches.
So, when choosing a 700x35c bike tire, it’s wise to be aware that the actual width might vary slightly. Factors like rim width and tire pressure can also influence the final mounted size. While the 700x35c marking provides a general guideline, understanding the history of tire sizing helps explain why it might not always be an absolute, precise measurement.
