Straight Sided Tyres

Straight sided tyres are similar in construction to wired on tyres and have inextensible wire beads. They were developed in the USA and employed either rims with a detachable flange or rims that could be reduced in diameter for tyre fitting and removal.

They were phased out for cars in the 1920s although they are still used on commercial vehicles.

The top table refers to tyre size and the bottom gives details of the detachable rims.

Tyre Size Information diameters and widths in inches
Tyre Size	Overall Diameter	Inflated Width	Recommended Rim Width	Max. Load in lbs.	Revs. Per Mile
31 x 4	31.50	4.20	2.75	900	673
32 x 4	32.45	4.20	2.75	1000	655
32 x 4.5	33.00	4.65	3.10	1250	643
43 x 4.5	34.80	4.70	3.10	1250	610
36 x 4.5	36.70	4.70	3.10	1250	578
33 x 5	33.50	5.20	3.75	1700	633
35 x 5	35.40	5.20	3.75	1700	599

Detachable Rim and Tyre Sizes - dimensions in millimetres except for tyres
Tyre Sizes	Outside Diameter	Inside Diameter	Overall width	Inside Width
18 x 3.5 25 x 3.5	492	451	87	59
19 x 3.5 27 x 4.40	518	476	87	59
20 x 3.5 30 x 5.00	543	501	87	59
21 x 3.5 29 x 4.40	568	527	87	59
22 x 3.5 32 x 5.00	594	552	87	59
23 x 3.5 31 x 4.00	619	578	87	59
25 x 3.5 32 x 3.5	670	626	87	59
18 x 4 27 x 4.75	498	451	99	68
19 x 4 28 x 4.75	522	476	99	68
20 x 4 29 x 4.50	548	500	99	68
21 x 4 30 x 4.50	573	527	99	68
22 x 4 32 x 4.00	598	552	99	68
23 x 4 31 x 4 or 33 x 5	624	578	99	68
24 x 4 or 33 x 4.5	649	601	99	68
25 x 4 or 34 x 4.5	675	626	99	68
18 x 4.5 or 28 x 5.00	502	450	111	79
19 x 4.5 or 29 x 5.00	527	476	111	79
20 x 4.5 or 30 x 5.00	552	501	111	79
21 x 4.5 or 31 x 5.00	578	525	111	79
22 x 4.5 or 32 x 5.00	603	551	111	79
23 x 4.5 or 32 x 4.5 or 33 x 5	629	577	111	79
24 x 4.5 or 33 x 4.5	654	601	111	79
25 x 4.5 or 34 x 4.5 or 35 x 5	679	626	111	79
18 x 5 or 30 x 6.00	502	449	127	95

19 x 5 or 31 x 6.00	527	476	127	95
20 x 5 or 32 x 6.50/6.20	552	500	127	95
21 x 5 or 33 x 6.00	578	525	127	95