20.8-30 Tractor Tires

Buying 20.8-30 tractor tires

20.8-30 is a wide rear tire for heavy utility and front-wheel-assist tractors. It carries more load and floats better than the 18.4-30 on the same rim diameter, and it is shorter overall than the 20.8-34 and 20.8-38. It is about 20.8 inches (528 mm) wide on a 30-inch wheel.

Most tires in this size are bias R-1. A radial version, 20.8R30, is also made for tractors that do a lot of field and road hours.

Easy to confuse

• 20.8-28, 20.8-30, 20.8-34 and 20.8-38 share the same width but fit different wheels.
• Moving up from 18.4-30: same rim diameter, but it needs a wider rim, more fender room and a front-to-rear ratio check.

What to check

• Tread: R-1 is the standard farm lug; ask about R-1W for wet ground and longer wear.
• Ply rating: match or exceed your current tires, especially if the tractor runs a loader or heavy three-point implements.
• Tube or tubeless: tell us what you run now, and whether the tires are filled with liquid ballast.
• Front-wheel-assist tractors: changing the rear size or construction changes the front-to-rear ratio. Check it before you order.
• Used tires: ask for the tread depth, the date code and photos of both sidewalls, and look for weather cracks.
• Pairs: replace both rears together so the tractor pulls straight.

Send the quantity, new or used, and the delivery location for a quote. More rear sizes are on our tractor tires page.

What do 20.8-30 tires cost on our site?

This size is not on a model listing yet. Send us the size and we check what we can supply.

How tall is the 20.8-30 tire?

The nominal overall diameter is about 65.4 in (1,660 mm), which gives a rolling circumference near 205 in (5,215 mm). That figure is an estimate that assumes an 85% aspect ratio, the usual rule for old inch sizes. Real tires vary by make and load, so treat it as a guide and use the tire diameter calculator or the lead-lag calculator before you change size on a front-wheel-assist tractor.

Is 20.8-30 a radial or a bias tire?

It is a bias-ply size. The dash in the size marks bias construction, which costs less and has stiffer sidewalls. See the radial vs bias guide.