Cycle tyres, history and nomenclature

Why is there different wheel sizes, what are their usages purposes, how they have historically evolved in cycling, why so many confusing dimensions for tyres!......

Like all beginners I have also gone through these questions and have eventually come to understand the following:.

26" wheel cycle: since the center of gravity is low and resultant control, they are better suited for trail riding, stunts, City bikes which can turn easily in the small bylanes etc, due to low turning radius.

Moreover 26" was the standard size in all MTBs when mountain biking started off initially. So we can easily get cost effective tyres and wheels in this size. ആദ്യ കാലങ്ങളിൽ ഈ size Tyre ധാരാളം മാർക്കറ്റിൽ വന്നിരുന്ന കാരണം ഇപ്പോഴും ഏറ്റവും വില കുറച്ച് കിട്ടുന്ന tyres and wheels ഈ സൈസിൽ ആണ്.

29" is for Downhill etc where rolling is the key while being off-road capable

27.5" is the midway option where more rolling is needed along with having maneuverability

 That is to say that 27.5 inch sized tyre is an in between option when maneuverability(26 wheel is more maneuverable than 27.5 due to its smaller diameter and hence smaller turning radius) is needed as well as good rolling speed (29 inches diameter wheel has more rolling speed due to its  higher diameter).

Selection of the wheel size depends upon the nature of ride planned, whether it's off road trail involving twists and turns where control, stability and precision turning is important (smaller diameter wheel is needed in these type of rides, 26" would be preferred if speed is not that important but control is, 27.5 would be preferred if speed is important but the trail involves not much of curves and turns at high speeds, 29" will be preferred if it's just Downhill and speed is important, not involving any serious curves).

Also 29" MTB is not meant for long rides on tarmac, for that a hybrid or road bike (depending on the condition of the road and speed required) with a 700mm diameter Tyre would be better.

See the explanation of Tyre sizes below, basically different places(for example the 700c nomenclature is due to the French standards)  different ways/standards of mentioning Tyre sizes, some mention in inches some mention in inches (in India we have both!

 The more accurate way of noting Tyre sizes are using the ISO standards or the ETRTO (European Tire and Rim Technical Organization) standards as explained in this video:

For more reading on the historical standards of tyres and wheels, click here https://www.centurycycles.com/tips/tech-talk-know-your-tire-size-pg1275.htm#:~:text=700C%20is%20used%20to%20refer,diameter%20of%20over%2029%20inches

Excerpt from the link above: 700C is used to refer to any tire, rim, or wheel with a 622mm BSD (Bead Seat Diameter) , but it could be on a skinny-tired road bike where the wheel has an actual diameter of only 660mm (which is actually a little LESS than 26 inches!), or a mountain bike with a wheel diameter of over 29 inches.

Read more at:  WHAT IS THE BEST WHEEL SIZE FOR A MOUNTAIN BIKE?

Want to know the pros and cons of each wheel size and what might work best for you? Read all about them here.