Width
Tyre profile width in millimetres. This designation is noticeably less common than inches (see Width above), but it is also used quite widely.
As for the width in the frame, in this case it is indicated by the distance between the sidewalls of the tyre installed on the disk and inflated (but not loaded). This is one of the parameters that determine compatibility with a particular disc: the tyre must be slightly wider than the rim. For the selection of rubber for specific disks in width, there are special tables.
On the modern market, among the popular sizes, there are such options in width:
205 mm,
215 mm,
225 mm,
235 mm,
245 mm,
265 mm,
275 mm,
285 mm,
295 mm,
305 mm,
315 mm,
385 mm,
425 mm,
435 mm,
445 mm.
Aspect ratio
Tyre profile height. This indicator determines how much the tyre protrudes above the disk. Specifies the profile height as a percentage of the width (see above). The lower the profile, the better the stability of the car on the road and the faster the rubber wears out; in turn, higher profiles are well suited for rough roads, primers and off-road.
In truck tyres, there are such options for profile height:
40%,
45%,
50%,
55%,
60%,
65%,
70%,
75%,
80%,
85%,
90%,
95%.
Rim diameter
Tyre inner diameter in inches. This parameter determines the possibility of installing the product on a specific car, more precisely, on a rim: the bore diameter must correspond to the diameter of the rim. The dimensions of the disk can be clarified by its marking or according to the documents for the car, in extreme cases, measure it yourself.
For trucks,
17" or less is considered small, over 24" is considered large. The most popular sizes in between include
17.5",
19.5",
20",
22.5" and
24".
Load index
The load index characterizes the maximum weight under which the tyre can be safely operated. As in the case of the speed rating described above, this indicator cannot be exceeded, otherwise unpleasant consequences are possible, up to accidents. Also note that when selecting according to the load index, it is worth considering the distribution of weight along different axes of the vehicle. And it is worth considering the maximum possible weight when the truck is loaded, in accordance with what to select
truck tyres for heavy loads.
