At SDJ Sports we appreciate that if you are new to cycling the sport can appear to be confusing with so many different styles of riding, racing, bicycles and not forgetting the all important riding accessories, clothing and equipment!
Tyres are available in wide range of sizes. These size vary by circumference, width and tread.
To make things a little more confusing some are measured in decimal widths and others are fractional widths. It is important to note that one will not fit the same as the other. For example, a 26" x 1 3/8 tyre is a different size to 26" x 1.5.
If you have a tyre that has worn out it is best to read the size from the sidewalk of that tyre to ensure you get the correct size.
There is also an ETRTO number (European Tire and Rim Technical Organization) on the side of the tyre. These numbers are normally in the following style 32-622. This indicates the width of 32mm and the tyre inner diameter of 622 mm.
Many people change the width and tread of their tyres. This can be fairly simple if you have a 26" decimal tyre or a 700c tyre. A 26" tyre can range anywhere between 26" x 1.00 to (commonly) 26" x 2.00. Some are slick and some have a grippy tread. Restrictions to size include rim width and frame width. You need to be sure the beading of the tyre is suitable for the rim and that the tread of the tyre won't rub on the frame. The same is true for the 700c tyres.
Once you have chosen which tyre there can often be a choice of compounds. This is the layup of the tyre itself. Many brands use different compounds of rubber. This is to get the best grip for the terrain the tyre is intended.
As the compounds become more complex you quite often jump to a folding bead. This means that instead of using a wire to help the tyre lock to the rim when inflated, strands of thread, often Kevlar are used. This allows the tyre to lock into the rim perfectly as the thread follows the exact form of the rim. Folding tyre command a higher price due to the quality and ride enhancement.