Tyre Conversion for Tractors

If tractors or other agricultural machines are to be retrofitted, for example with dual wheels or row-crop tyres, it must be ensured that the vehicle complies with the German Road Traffic Licensing Regulations (StVZO) if it is also to be used on public roads.

Tyre sizes not listed in the vehicle registration certificate must be added. For this purpose, a declaration of no objection (“Unbedenklichkeitsbescheinigung”) from the vehicle manufacturer serves as consent for entry by the technical inspection authority.

For four-wheel-drive tractors with different tyre dimensions on the front and rear axles, the rotational speed ratio between the front and rear axles is specified by the vehicle manufacturer based on the vehicle’s mechanical data and the intended tyre equipment. In most cases, the tractor’s front axle has a lead, meaning the front wheels run approximately 2% to 4% faster than the rear wheels.

A tyre size that differs from the original specification when changing the tyre equipment on one of the two axles should only be selected if the rolling circumference ratio (front axle to rear axle) remains within the tolerances specified by the vehicle manufacturer.

Tyre Conversion Table

Please note: Some conversions require a different rim size.

Base Size	Series 85	Wide 70	Wide 65	Super Wide	Row-Crop
Standard	mounted on standard rims			special rims
6.50 R 16		260/70 R 16
7.50 R 16		280/70 R 16	320/65 R 16
7.50 R 18		280/70 R 18	320/65 R 18	11 LR 16
10.5 R 18			340/65 R 18
12.5 R 18
7.50 R 20		280/70 R 20	340/65 R 18
9.5 R 20	250/85 R 20	300/70 R 20
10.5 R 20			340/65 R 20
11.2 R 20	280/85 R 20	320/70 R 20
12.4 R 20	320/85 R 20	360/70 R 20	420/65 R 20
14.5 R 20		405/70 R 20			9.5 R 24
8.3 R 24	220/85 R 24
9.5 R 24	250/85 R 24	300/70 R 24		420/65 R 20
11.2 R 24	280/85 R 24	320/70 R 24		425/75 R 20	8.3 R 28
12.4 R 24	320/85 R 24	360/70 R 24	420/65 R 24	425/75 R 20	9.5 R 28
13.6 R 24	340/85 R 24	380/70 R 24	440/65 R 24	445/70 R 24	8.3 R 32
					11.2 R 28

14.9 R 24	380/85 R 24	420/70 R 24	480/65 R 24	17.5 LR 24	9.5 R 32
					270/80 R 32
16.9 R 24	420/85 R 24	480/70 R 24	540/65 R 24	19.5 LR 24	8.3 R 36
					11.2 R 32
14.9 R 26	380/85 R 26			19.5 LR 24	11.2 R 32
16.9 R 26	420/85 R 26	480/70 R 26	540/65 R 26		9.5 R 36
18.4 R 26	460/85 R 26	520/70 R 26		580/70 R 26	11.2 R 36
				19.5 LR 28
28 LR 26			750/65 R 26		13.6 R 38
11.2 R 28	280/85 R 28	320/70 R 28	440/65 R 24		8.3 R 32
12.4 R 28	320/85 R 28	360/70 R 28	420/65 R 28	17.5 LR 24	9.5 R 32
13.6 R 28	340/85 R 28	380/70 R 28	440/65 R 28	19.5 LR 24	8.3 R 36
					11.2 R 32
14.9 R 28	380/85 R 28	420/70 R 28	480/65 R 28	540/65 R 26	9.5 R 36
					12.4 R 32
16.9 R 28	420/85 R 28	480/70 R 28	540/65 R 28	19.5 LR 28	11.2 R 36
				580/70 R 26
14.9 R 30	380/85 R 30	420/70 R 30		480/70 R 28	11.2 R 36
				580/70 R 26	12.4 R 32
				19.5 LR 28
				540/65 R 28
16.9 R 30	420/85 R 30	480/70 R 30	540/65 R 30	620/70 R 26	11.2 R 38
				600/65 R 28
				710/55 R 30
18.4 R 30	460/85 R 30	520/70 R 30		620/75 R 26	8.3 R 44
				750/65 R 26	9.5 R 42
				1000/50 R 25
23.1 R 30		620/75 R 30
12.4 R 32	320/85 R32				8.3 R 36
24.5 R 32		650/75 R 32
30.5 LR 32			800/65 R 32		18.4 R 38
14.9 R 34	380/85 R 34			1000/50 R 25	9.5 R 42
16.9 R 34	420/85 R 34	480/70 R 34	540/65 R 34	620/75 R 26	9.5 R 44
				750/65 R 26	11.2 R 42
				600/70 R 28	13.6 R 38
18.4 R 34	460/85 R 34	520/70 R 34	600/65 R 34	600/70 R 30	11.2 R 44
				1000/50 R 25	300/95 R 42
				620/75 R 30
23.1 R 34		620/75 R 34			11.2 R 48
				650/75 R 32
12.4 R 36	320/85 R 36				9.5 R 40
13.6 R 36	340/85 R 36
13.6 R 38	340/85 R 38			480/70 R 34	9.5 R 44
				540/65 R 34	11.2 R 42
15.5 R 38				540/65 R 34	9.5 R 44
				480/70 R 34
14.9 R 38	380/85 R 38			620/75 R 26	11.2 R 44
16.9 R 38	420/85 R 38	480/70 R 38	540/65 R 38	620/75 R 30	9.5 R 48
				600/65 R 30	11.2 R 46
18.4 R 38	460/85 R 38	520/70 R 38	600/65 R 38	650/75 R 32	11.2 R 48
				24.5 R 32
				620/75 R 34
				800/65 R 32
20.8 R 38	520/85 R 38	580/70 R 38	650/65 R 38	680/75 R 32	320/90 R 46
				800/65 R 32	13.6 R 48
				620/75 R 34
				620/70 R 38
				1050/50 R 32
				900/55 R 32
18.4 R 42	480/80 R 42				13.6 R 48
20.8 R 42	520/85 R 42	580/70 R 42	650/65 R 42	650/75 R 38	11.2 R 54
				900/50 R 42
				900/60 R 32
				850/55 R 42
				680/85 R 32
				710/70 R 38
				710/75 R 34
				620/70 R 42
20.8 R 46	520/85 R 46	620/70 R 46		650/85 R 38	480/80 R 50
				800/70 R 38
				710/70 R 42

Our qualified specialists are at your side throughout the year, offering expert advice and hands-on support to keep your machinery fleet operational and to improve its performance.

When you order spare parts and tyres from us, we know that you are often on your own during installation. If you encounter any issues, simply use our service contact form. We will get in touch with you promptly.

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Tyre Conversion for Tractors

Tyre Conversion Table