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235/45 R21 Tyres

Everything we know about the 235/45 R21 tyre size: 2 owner reviews covering 16,000 miles of driving, and EU label data for the tyres you can actually buy in it.

  • 2owner reviews
  • 16,000 milescovered on them
  • 80tyres made in this size
235/45 R21 To scale, mm
Ø 745 235 106 21" 106

235/45 R21 EU tyre label data

EU label values are declared for each individual size, so the figures here are exact for 235/45 R21 rather than a range across a model. 71 tyres carry label data in this size. The most common load index is 101 (up to 825 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). 34 tyres in this size carry the 3PMSF severe snow marking.

A Best wet grip

31 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: 12 tyres in this size reach rolling resistance class A. The highest scoring on Tyre Reviews:

67dB Quietest tyres

The quietest 235/45 R21 tyres are labelled at 67 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 235/45 R21 mean?

A 235/45 R21 tyre is 235 mm wide, its sidewall is 45% of that width (106 mm) tall, and it fits a 21 inch wheel. That gives an overall diameter of roughly 745 mm.

235/45 R21 nominal dimensions
Section width235 mm
Sidewall height106 mm
Rim diameter21" (533 mm)
Overall diameter≈ 745 mm
Circumference≈ 2,340 mm
Revolutions per km≈ 427
Revolutions per mile≈ 688

Also written as

235/45R21 235/45 ZR21 235-45-21 235 45 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 drivers say about their 235/45 R21 tyres

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

76%
Michelin Pilot Sport 4 SUV 235/45 R21 Audi 15,000 miles July 7, 2026
This review is intended to be a comparison of the same tyre on different cars, having experienced a full set of PS4 SUV with my previous Q5 from start to end. In this case, I progressively installed a front pair (due to a front puncture of the OE tyres), then a rear pair (due to wear of the OE tyres) on my Q4 e-tron which I have had for about 2 years. So this is for anyone cross-referencing the same tyre but who would like to find out the difference between a regular car and an EV.

Usually, SUVs come with regular tyres, some sporty but most of them are SUV-fitted tyres. My previous full set of PS4 SUV on the Q5 was preceded by the OE, then Latitude Sport. I found the improvement from one to the other very good, and never once was fuel consumption questioned because the figures were similar.

However, this time, I have progressively installed summer performance SUV tyres on my EV over the original EV-specific tyres (Turanza Eco). As Jon has highlighted before, the half-half setup of front performance and rear EV-specific tyres gave rise to a fun (but technically less safe) oversteering car which did not impact the energy consumption too much. I was getting about 6.4km/kWh for the first 10000km with full EV tyres, then about 5.9-6.1km/kWh for about 20000km on the mixed setup, which has gone down to 5.5-5.7km/kWh on the full PS4 SUV setup.

Apart from the figures, I feel that my Q4 e-tron is not rolling as efficiently as before as the tyres just feel a bit heavier. I'm jabbing at the accelerator fractionally longer, and not getting the same about of regeneration. Numerically, going from 6.4 down to 5.7 is not a great deal (just 10%), it does bother me as a numbers person. Over time, my decision to prioritise a higher performing tyre is going to cost me a bit more in the wallet. However, it also took a little bit of fun away from getting good consumption numbers to which I will have to get used to during the life of this tyre, which I expect to last at least 35000km. So far the fronts have eked out 20000km and the tread is still looking good, while the new rears have done less than 1000km.

At the speeds I'm allowed to drive, which is less than 100km/h, with frequent tropical rain, I don't think that my car really needs the full PS4 performance, and I'm thinking of switching to the PS5 Energy when the time is up for this set. I mean, it still feels great on the road, the grip is fantastic, and the braking is really stable and straight, but I'm not sure they are a good match for an EV.

Overall, these are great tyres. If consumption or rolling resistance is not your priority, they are still suitable for EVs. However, if you are an EV driver and want to save on costs and can give up a bit of grip for an EV-specific tyre which will perform almost similarly, you will be rewarded with exactly that.
86%
Winrun R330 235/45 R21 Mercedes Benz 1,000 miles April 23, 2026
Fixed my GLC crabbing and juddering issue! Matches Expensive tyres for the fraction of the price

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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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