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315/40 R21 Tyres

Everything we know about the 315/40 R21 tyre size: 1 owner reviews covering 900 miles of driving, and EU label data for the tyres you can actually buy in it.

  • 1owner reviews
  • 900 milescovered on them
  • 104tyres made in this size
315/40 R21 To scale, mm
Ø 785 315 126 21" 126

315/40 R21 EU tyre label data

EU label values are declared for each individual size, so the figures here are exact for 315/40 R21 rather than a range across a model. 83 tyres carry label data in this size. The most common load index is 115 (up to 1,215 kg per tyre). Speed ratings on offer: (Y) (301 km/h), Y (300 km/h), W (270 km/h), V (240 km/h), H (210 km/h), T (190 km/h), Q (160 km/h). 34 tyres in this size carry the 3PMSF severe snow marking.

A Best wet grip

29 tyres in this size hold the top EU wet grip rating, class A. The highest scoring on Tyre Reviews:

A Lowest rolling resistance

The most fuel efficient choice: 4 tyres in this size reach rolling resistance class A. The highest scoring on Tyre Reviews:

68dB Quietest tyres

The quietest 315/40 R21 tyres are labelled at 68 dB external noise:

Label values come from the EU EPREL database and apply to the EU market versions of each tyre. Wet grip and rolling resistance run from class A (best) to E; noise is the measured drive-by figure. A good label is a floor, not a verdict - the tests and owner ratings above tell you far more.

What does 315/40 R21 mean?

A 315/40 R21 tyre is 315 mm wide, its sidewall is 40% of that width (126 mm) tall, and it fits a 21 inch wheel. That gives an overall diameter of roughly 785 mm.

315/40 R21 nominal dimensions
Section width315 mm
Sidewall height126 mm
Rim diameter21" (533 mm)
Overall diameter≈ 785 mm
Circumference≈ 2,467 mm
Revolutions per km≈ 405
Revolutions per mile≈ 652

Also written as

315/40R21 315/40 ZR21 315-40-21 315 40 21

Figures are calculated from the nominal size. A loaded, rolling tyre runs a few percent smaller, and true widths vary slightly between makes.

Comparing two sizes? Use the tyre size calculator →

What cars use 315/40 R21 tyres?

The cars most often running this size in our owner reviews. Each links to the best rated tyres for that exact car.

What drivers say about their 315/40 R21 tyres

The most recent owner reviews fitted in this size, in their own words.

89%
Vredestein Wintrac Pro 315/40 R21 Mercedes Benz GLE 350de 900 miles December 16, 2022
Was originally going for Pilot Alpin 5 SUV, but there were some delays when ordering so got these instead in 275/45/21 and 315/40/21 on a 2850kg car. There has been ice, snow, slush, dry and wet weather since I put these on and I must say I am impressed over how these perform. For a heavy SUV these tyres feel very well, cant really compare it to anything else as this is the first winter with this car, but we have a EV SUV that weighs 2650kg with Nokian R3 and I feel the Vredesteins suit a heavier car better the Nokians. Braking and grip on snow felt pretty much the same, although I had an impression of more control with the Vredesteins when braking and trying to provoke sliding. They aren’t remarkable on ice, but rarely non studded tyres are. Consumption is a bit higher than the sportcontact 6 summer tires and road noise is pretty much the same. Will probably try the Pilot Alpin 5 due to lower rolling resistance next time.

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Where this data comes from

Owner ratings are submitted through the review form on this site, naming the tyre, the size and the distance covered, and are checked by hand before publication. Test results come from independent published tyre tests indexed by size, and label values from the EU EPREL database.

About the TR Score

The Tyre Reviews Score rates each tyre out of 10 using independent test results and the full body of owner reviews, so you can check a car-specific ranking against the wider evidence.

Who does the testing

Every test published as a Tyre Reviews test is run by Jonathan Benson, who has been testing tyres independently since 2007.

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