In order to ensure that tires have sufficient frame clearance, tire manufacturers generally prefer to keep production closer to the lower end of the permitted tolerance (+/- 3 mm).
Carcass casing materials have become more and more sophisticated over time. That reduces the tire widening after the fitting.
Furthermore, inflation pressure also plays a major role. With maximum inflation pressure the tire becomes wider than with low pressure. And a recently fitted tire still widens over time. This can make a difference of 1 to 2 mm.
The tire width is measured at the widest point, i.e. outside the lug.

The question whether tires will fit into a particular frame is often asked in relation to our ultra-wide tires.
Please bear in mind that with the large number of different bicycle models it is impossible to check the compatibility of all frames and tires.
The following list shows the exact diameters and widths of our ultra wide tires. This should allow you to identify if there is sufficient frame clearance for the selected tire.
Inches | Size | Tire | Maximum width (A) |
Maximum diameter (B) |
Bead seat diameter with maximum width (C) |
24" |
60-507 | Crazy Bob | 61 | 631 | 570 |
26" |
60-559 | Big Apple | 58 | 683 | 625 |
Big Ben | 60 | 689 | 628 | ||
Crazy Bob | 64 | 685 | 629 | ||
Dirty Dan | 65 | 694 | 623 | ||
Fat Frank | 61 | 687 | 630 | ||
Hans Dampf | 60 | 684 | 621 | ||
Ice Spiker/Ice Spiker Pro | 60 | 686 | 615 | ||
Magic Mary | 60 | 687 | 621 | ||
Nobby Nic | 60 | 686 | 624 | ||
Rock Razor | 60 | 683 | 620 | ||
Rocket Ron | 60 | 687 | 628 | ||
Space | 63 | 693 | 621 | ||
Super Moto | 58 | 684 | 624 | ||
65-559 | Magic Mary | 67 | 701 | 636 | |
27,5" |
60-584 | Dirty Dan | 66 | 714 | 649 |
Hans Dampf | 63 | 710 | 645 | ||
Magic Mary | 62 | 713 | 641 | ||
Nobby Nic | 62 | 712 | 648 | ||
Rock Razor | 61 | 708 | 637 | ||
65-584 | Magic Mary | 67 | 720 | 695 | |
Nobby Nic | 68 | 719 | 691 | ||
Rock Razor | 67 | 713 | 690 | ||
Ice Spiker Pro | 69 | 724 | 697 | ||
70-584 | Magic Mary | 72 | 727 | 697 | |
Nobby Nic | 72 | 723 | 692 | ||
75-584 | Nobby Nic | 77 | 732 | 694 | |
28" |
50-622 | Big Apple | 48 | 722 | 670 |
Big Apple Plus | 51 | 729 | 677 | ||
55-622 | Big Apple | 55 | 741 | 688 | |
Big Ben | 57 | 744 | 688 | ||
Marathon Almotion | 55 | 744 | 687 | ||
60-622 | Big Apple | 59 | 750 | 691 | |
29" |
Hans Dampf | 62 | 749 | 684 | |
Magic Mary | 61 | 751 | 678 | ||
Nobby Nic | 59 | 751 | 687 | ||
Racing Ralph | 59 | 747 | 686 | ||
Super Moto | 59 | 750 | 691 | ||
65-622 | Nobby Nic | 64 | 754 | 726 |

The inner diameter of the tire must match the rim bead seat diameter. For instance, a tire size 37-622 fits on a 622 x 19C rim.
Furthermore, the tire width must match the inner rim width. The following table shows possible combinations of tire widths and inner rim widths according to ETRTO, complete with additional Schwalbe recommendations.

In order to accurately program a bicycle computer, it is generally necessary to enter the exact tire circumference.
The tire circumference varies depending on the rim, the inflation pressure and the load on the tire. For these reasons, it is not possible to list an exact tire circumference. In order to accurately program a bicycle computer, we recommend a simple rolling test with the rider on the bicycle.
Inch | ETRTO | Approximate Tire circumference |
16" |
50-305 | 1265 mm |
35-349 | 1315 mm | |
37-349 | 1330 mm | |
18" |
40-355 | 1380 mm |
50-355 | 1440 mm | |
20" |
23-406 | 1420 mm |
28-406 | 1450 mm | |
35-406 | 1510 mm | |
40-406 | 1540 mm | |
47-406 | 1580 mm | |
50-406 | 1600 mm | |
54-406 | 1620 mm | |
24" |
47-507 | 1900 mm |
50-507 | 1910 mm | |
54-507 | 1930 mm | |
24" |
57-507 | 1955 mm |
60-507 | 1980 mm | |
26" |
35-559 | 1990 mm |
40-559 | 2030 mm | |
47-559 | 2050 mm | |
50-559 | 2075 mm | |
54-559 | 2100 mm | |
57-559 | 2120 mm | |
60-559 | 2160 mm | |
37-590 | 2100 mm |
Inch | ETRTO | Approximate Tire circumference |
27" |
32-630 | 2200 mm |
27,5" |
54-584 | 2195 mm |
57-584 | 2215 mm | |
60-584 | 2240 mm | |
28" |
20-622 | 2100 mm |
28" |
23-622 | 2125 mm |
25-622 | 2135 mm | |
28-622 | 2150 mm | |
30-622 | 2160 mm | |
32-622 | 2170 mm | |
35-622 | 2185 mm | |
37-622 | 2200 mm | |
40-622 | 2220 mm | |
42-622 | 2230 mm | |
47-622 | 2250 mm | |
50-622 | 2280 mm | |
40-635 | 2250 mm | |
29" |
54-622 | 2310 mm |
57-622 | 2330 mm | |
60-622 | 2340 mm |

The approximate tire circumferences for the most common sizes are listed in the table below.