American Classic clincher tires are compatible with clincher rims that meet current global design standards set by E.T.R.T.O. and fit within the approved rim width range per tire size. We cannot guarantee tire compatibility with rims that do not meet current E.T.R.T.O. standards. To determine if your current rim meets E.T.R.T.O. standards, please contact your wheel or rim manufacturer.
For Tubeless Ready tires, if the tire and rim both meet E.T.R.T.O. standards for tubeless systems, and the tire is placed on an appropriate width rim, the combination is compatible. However, more care must be taken with regards to tire pressure in hookless systems. Tire pressures for hookless systems are lower than hook-bead rim systems. E.T.R.T.O. sets a maximum pressure for hookless systems at 72.5psi (5 bar). Some hookless rim and Tubeless Ready tire models require lower maximum pressures. Failure to abide by the lowest of these maximum pressures can lead to the tire and rim separating and harm to the rider. Based on E.T.R.T.O.’s maximum pressure limit, we request that American Classic tires with a maximum rated pressure above 72.5psi not be used on hookless rims.
When using American Classic tires on hookless rims, the following must be followed:
- Only use Tubeless Ready tires with hookless rims. DO NOT use Tube-Type tires.
- Only use Tubeless Ready tires that have a maximum pressure below 72.5 psi on hookless rims.
- Only combine tires with the appropriate width rims as set by E.T.R.T.O. (see the chart below)
- Follow all instructions provided by the rim or wheel manufacturer regarding setting up the base tape. DO NOT add more layers of tape to the rim than is recommended.
- Stay below the lowest of the two maximum pressures found for the tire and the rim.
The bicycle industry tends to cling to tradition, and rim sizes are a particular place where the nomenclature can introduce confusion. Rim sizes like 700c, 29”, and 650b come from an era where many countries had their own way of measuring tires and rims. Today there are standards, like E.T.R.T.O., which provide a system that is followed globally. American Classic uses both the traditional and the global standards sizes on each tire.
The E.T.R.T.O. standards are broken into two numbers: the width and the bead seat diameter. An example is 25-622 which refers to a 25mm wide tire designed for a rim that has a 622mm bead seat diameter.
With regard to rim sizes, 700c and 29” are both based on a 622mm BSD rim. Thus, the diameter of a 29” mountain bike rim should be the same as a 700c road or gravel rim. And both 27.5” and 650b are based on a 584mm BSD rim. Thus, the diameter of a 27.5” mountain bike rim should be the same as a 650b gravel or city bike rim. The bicycle industry tends to use 700c, or 650b, when referring to narrower tires and 29”, or 27.5”, when referring to larger volume tires. This is due to tradition.
For a thorough explanation of tire and rim sizes of the past, and why we call them what we do today, see Sheldon Brown's Tire Sizing Systems page.
Compatible Tire and Rim Widths
It is important to match the appropriate inner rim width and tire casing size to avoid rim damage, tire roll off, and to optimize performance. Too narrow of a rim for the tire forces the bead to be pulled too close together, the tire tread to be flattened, stability and cornering to suffer, and the risk of tire rolling off the rim while cornering increases. Too wide of a rim for the tire spreads the tire bead too wide moving cornering lugs to the face of the tread, exposes the tire sidewalls to damage, reduces impact absorption capabilities to the point of risking rim damage, and increases the potential of a tire blowing off the rim. Using the correct rim for the desired tire casing size will yield a better performing, longer lasting tire.
American Classic designs our tires using design size standards specified by E.T.R.T.O.. In the illustrations below, the ‘design size’ rim width is the larger number in the center of the rim width range. A tire is mounted to the designated design size rim, inflated, let sit for 24 hours, and then inflated again. At that point the tire will match the listed size. In line with this, a 32mm Torchbearer tire will measure 32mm in width when mounted on a clincher rim that has an internal width of 21mm after 24 hours of inflation. Mounting this same tire on a narrower rim will result in a narrow tire. And mounting this same tire on a wider rim will result in wider tire width.
To determine your rim’s width, measure where shown in the illustrations below.