Skip to content
Tiremaxx Service Centers
20.8-42 farm tires at Tiremaxx in St. Joseph, MN

Agricultural & Farm Tires

20.8-42 Farm Tires

What 20.8-42 means, what else fits the same wheel, and how to get the right load range, from the Tiremaxx tire crew in St. Joseph, MN.

20.8-42 tires we carry

1 option in this size. Call (320) 363-7246 for price and availability, or request the one you want.

← Search all agricultural & farm sizes

Our lineup refreshes from the warehouse system every 30 minutes. Call to confirm availability before you drive out.

Wheel
42"
Construction
Bias-ply
Section width
20.8"
Overall dia.
—

What 20.8-42 means

Every number on the sidewall is telling you something. Here's this one, decoded:

  • 20.8Section widthAbout 20.8 inches across the widest part of the tire.
  • –ConstructionBias-ply. The plies run diagonally, which gives a stiff, tough sidewall.
  • 42Wheel diameterFits a 42-inch wheel. This is the number that has to match your rim exactly.

Equivalent sizes

The equivalent of 20.8-42 in the other construction is 520/85R42. Bias and radial versions stand close to the same height but are built differently, so tell us which one you run.

Size is only half the answer

Two 20.8-42 tires can be built for very different work. Ply rating or load index sets how much each tire carries, and the tread code sets the job: R-1 and R-1W for drive traction, F-2 for front steering, I-1 for implements and wagons. Tell us the tractor or implement and how it's used, and we'll match the tire to it.

Other sizes on a 42" wheel

These share your rim diameter. Whether one of them will actually work depends on rim width, load range and fender clearance. Ask us before you switch.

20.8-42 questions, answered

20.8: About 20.8 inches across the widest part of the tire. –: Bias-ply. The plies run diagonally, which gives a stiff, tough sidewall. 42: Fits a 42-inch wheel. This is the number that has to match your rim exactly.

Many farm sizes are made both ways. Radials put more tread on the ground, ride smoother and are easier on the soil; bias tires cost less and shrug off stubble and sidewall knocks. Equivalent bias and radial sizes are close in height but not identical, so tell us if you're mixing them on one axle or on a front-wheel-assist tractor and we'll check it works.

We carry 18.4-42 in the same 42-inch wheel diameter. Sharing a rim diameter doesn't guarantee a swap will work, though. Rim width, load range and clearance all have to line up. Call (320) 363-7246 and we'll tell you straight whether a change makes sense.

They're equivalent sizes. 20.8-42 and 520/85R42 fit the same wheel diameter and stand close to the same height, but bias and radial tires are built differently, so they shouldn't be mixed on one axle without checking. Tell us which one you run and we'll match it.

Stock moves, so the honest answer is to check. Send us the size through the availability request on this page or call (320) 363-7246. We'll tell you what we have on the shelf, what load ranges are available and how fast we can get anything we'd need to order.

← All agricultural & farm tire sizes

Pull up to the counter

Need 20.8-42 for the farm?

Tell us the size and load range and we'll prepare a no-pressure quote.

Schedule ServiceCall (320) 363-7246