There are dozens of standard artwork sizes, all of which are based on the size of the picture or artwork that will be placed in the frame. Our chart of standard sizes lists them all. You can still customise the look and feel of your frame after selecting one of these popular sizes. Tubular tyres require skilled fitting; if unsure, consult a suitably trained cycle mechanic. Other sizes including 26" may be encountered; these are rare and it is advisable to make a direct match with a rim before buying. Recommended pressures

The three-digit number after the dash is the more important. This is the bead diameter at which the tyre fits onto the rim. How do you know what size tyres will fit your bike? It should be easy: buy exactly the same model of tyre as those already on the bike. Of course, this isn’t much help if identical tyres aren’t readily available, if you fancy something different or if you’re looking for replacements in unusual and hard-to-find sizes.

Other

The initial two-digit number is the tyre section and roughly indicates the tyre width. Its actual width is normally less, but varies according to how the tyre is designed and the width of rim to which it is fitted. But the height of the tyre usually corresponds quite closely to tyre section, so overall diameter approximately equals the bead diameter plus twice the section. Proper fraction button is used to change a number of the form of 9/5 to the form of 1 4/5. A proper fraction is a fraction where the numerator (top number) is less than the denominator (bottom number). Tyres suitable for use with dedicated tubeless rims, or with a conversion system which employs tape to seal the rim bed, are marked using a sidewall decal such as tubeless-compatible, tubeless-ready, tubeless-easy or similar. They have a special stretch-resistant folding bead made, usually, of carbon fibre. Even worse, the same or very similar markings can sometimes be found on completely different sizes of tyre: 26×1½ and 26x1.5. It might be supposed that these two tyres are both notionally 26" diameter and one and a half inches in width, but 26×1½ is a whole inch bigger than 26×1.5.

On the other hand it increases the stress on the sidewall of the tyre. Mountain bike tyres are designed to take this extra stress but road tyres are not.

Sometimes you can’t find any ISO size on a tyre, only the old-school markings. Although they’re familiar they can be confusing. Tyres of the same size may come with lots of different markings: 28×1¼×15/8, 28×1¾×1¼ or 700×32C, for example, which are all 32-622. Tubeless tyres, as the name suggests, do away with an inner tube and, in its absence, are reliant on the shape and tightness of the tyre bead to ensure the tyre doesn’t blow off the rim at high inflation pressures; in a conventional clincher tyre, the inner tube keeps the bead securely located under the rim hook. A very popular set of standard sizes in the UK are the "A" series of paper sizes, such as A4 or A2. We have a handy guide all about "A" paper sizes too. Custom Sizes Starting with the ones digit of the bottom number, the multiplier, multiply it by the last digit in the top number