315/30 R21 Tyres in Park Royal
315 mm wide, 30% profile, for a 21-inch wheel. Fitted at our NW10 workshop, with live prices online.
315/30 R21 is a 21-inch tyre, 315 mm wide, with a sidewall 94.5 mm tall (30% of the width). We fit 315/30 R21 tyres at our Park Royal garage in NW10, with balancing, a new valve and disposal of the old tyre included. The price depends on the brand: see live prices for 315/30 R21. It is fitted to cars such as the Porsche 911 and Porsche Panamera.
What 315/30 R21 means
- 315: the tyre is 315 mm wide, measured across the sidewalls.
- 30: the sidewall height is 30% of the width, so 315 × 30% = 94.5 mm.
- R: radial construction. A ZR in the same place is the same size with a speed marking for over 240 km/h.
- 21: it fits a 21-inch wheel. Overall diameter is 21 × 25.4 mm plus two sidewalls: 722.4 mm.
The load index and speed rating follow the size on the sidewall (for example 91V). Replace like for like or higher, as your handbook states.
Cars that use 315/30 R21
Manufacturer and tyre-maker fitment listings give 315/30 R21 for these models, usually as one of several wheel options. The size on your own tyres, or on the placard in the door frame, is the one to match.
| Make | Model | Generation |
|---|---|---|
| Porsche | 911 | 992 (2019-, incl. 2024 facelift) |
| Porsche | Panamera | 971 / G2 (2016-2024, incl. 2020 facelift and Sport Turismo) |
What to look for in a 315/30 R21 tyre
- Low profile, less cushion. A 94.5 mm sidewall on a 21-inch wheel leaves little to absorb a pothole or a kerb, so check for bulges and rim damage after a hard hit, and have the wheel alignment checked if the steering pulls or the new tyres wear on one edge.
- Winter or all-season. If you want winter or all-season tyres in 315/30 R21, the live list shows what is made in this size today; not every pattern is made in every size.
315/30 R21 tyres by price band
These are the brands we fit, by price band. Which of them make 315/30 R21, and at what price today, is on the live price list.
- Premium: Continental, Pirelli, Hankook, Yokohama, Bridgestone, Dunlop, Goodyear, Michelin
- Mid-range: Avon, Nankang, Roadstone, Kumho
- Budget: Accelera, Linglong
Prices for 315/30 R21 depend on the brand — see live fitted prices for 315/30 R21.
Book online, call 020 3886 2355 or WhatsApp 07476 586 589. We fit at Unit 4 Unimix House, Abbey Road, Park Royal, London, NW10 7TR, balancing and a new valve included.
Sizes next to 315/30 R21
Same 21-inch rim, one step wider, narrower, taller or lower.
Sizes with a similar overall diameter
These sizes are within 3% of the 722.4 mm diameter of 315/30 R21 on paper, and within 20 mm of its width. That alone does not make them approved for your car: check the handbook or the door placard, and keep one size across an axle.
| Size | Overall diameter | Difference |
|---|---|---|
| 305/35 R20 | 721.5 mm | -0.1% |
| 315/35 R20 | 728.5 mm | +0.8% |
| 295/35 R20 | 714.5 mm | -1.1% |
| 295/30 R21 | 710.4 mm | -1.7% |
| 295/35 R21 | 739.9 mm | +2.4% |
| 295/40 R20 | 744 mm | +3.0% |
See all tyre sizes, or read how our tyre fitting works.
Frequently asked questions
Is 315/30 R21 the same as 315/30 ZR21?
Yes, the dimensions are the same. The Z marks a tyre rated for over 240 km/h (149 mph); the exact rating is the letter after the load index, such as W or Y. Fit at least the speed rating your handbook gives for the car.
Can I fit 305/35 R20 instead of 315/30 R21?
Only if 305/35 R20 is listed for your car. On paper it is 721.5 mm tall against 722.4 mm for 315/30 R21, a 0.1% difference, so the speedometer would barely change. It also needs a 20-inch wheel instead of a 21-inch one. Wheel width, arch clearance, load index and speed rating must suit the car too, so check the handbook or the door placard, and fit one size across an axle.
How tall is a 315/30 R21 tyre?
About 722.4 mm (28.4 inches) across when new and unloaded: the 21-inch rim (533.4 mm) plus two sidewalls of 94.5 mm, which is 30% of the 315 mm width. Real tyres differ by a few millimetres between brands and patterns.
Which cars use 315/30 R21 tyres?
Fitment listings give 315/30 R21 for the Porsche 911 and Porsche Panamera. One model can use several sizes depending on its wheels, so check the sidewall of your own tyres before you book.
Same-Day Tyre Fitting & Walk-Ins Welcome
New tyres fitted while you wait, plus puncture repairs, wheel balancing and battery replacement at our Park Royal workshop. No appointment needed for tyres, just call in.