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Tiremaxx Service Centers
340/65R18 farm tires at Tiremaxx in St. Joseph, MN

Agricultural & Farm Tires

340/65R18 Farm Tires

What 340/65R18 means, what else fits the same wheel, and how to get the right load range, from the Tiremaxx tire crew in St. Joseph, MN.

Wheel
18"
Construction
Radial
Section width
13.4"
Overall dia.
35.4"

What 340/65R18 means

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

  • 340Section width340 mm (about 13.4 in) across the widest part of the tire.
  • 65Aspect ratioThe sidewall height is 65% of the section width. A lower number means a shorter sidewall.
  • RConstructionRadial. The body plies run across the tire. Radials generally run cooler at highway speed and wear more evenly.
  • 18Wheel diameterFits a 18-inch wheel. This is the number that has to match your rim exactly.

Size is only half the answer

Two 340/65R18 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 an 18" 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.

Similar overall diameter

Within about 3% of 340/65R18's 35.4" height, on various wheel sizes.

340/65R18 questions, answered

340: 340 mm (about 13.4 in) across the widest part of the tire. 65: The sidewall height is 65% of the section width. A lower number means a shorter sidewall. R: Radial. The body plies run across the tire. Radials generally run cooler at highway speed and wear more evenly. 18: Fits a 18-inch wheel. This is the number that has to match your rim exactly. Altogether that works out to roughly 35.4 inches of overall diameter.

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 7.50-18, 440/55R18 in the same 18-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.

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 340/65R18 for the farm?

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

Schedule ServiceCall (320) 363-7246