← All projectsSep 2026
GT3 RS Wheel Replica
A replica of the Porsche 911 GT3 RS wheel, made to experiment with vapor smoothing.
A replica of the Porsche 911 GT3 RS front wheel, which I printed in ABS on a Bambu Lab H2D and then vapor smoothed with acetone. The print is 275 mm across, about half scale: my CAD is the full-size wheel, 545 mm across the lips and 264 mm deep (275 / 545 = 0.50), with split spokes running out from a single centre bore to a deep barrel.
Rolling it
The wheel from my CAD. Scroll and it rolls three full turns about its axle, then the view swings around it to show every side.
Rolling
It turns about its axle as you scroll. At 545 mm across, each turn rolls 1.71 m of lip along the ground.
Three turns
Three turns: 5.14 m on the bare lips. On the car, the 700 mm front tyre would carry it 6.60 m.
The face
Seven spokes leave the centre bore, and each splits in two before the rim: 14 arms meet the lip (counted in the CAD).
Side on
From the side, the barrel runs 264 mm from the face to the back lip.
The back
From behind: the inside of the barrel, the backs of the spokes and the bore through the hub.
From above
Both lips are 545 mm across; between them the barrel narrows to 453 mm (measured from the CAD).
The wheel, from my CAD, rolling as you scroll
Which wheel it is
The GT3 RS runs a 20 in wheel at the front and a 21 in wheel at the rear. My replica is the front one:
Calculation Front or rear?
| Front wheel | 10 J x 20 (20 in rim, 10 in wide), 275/35 ZR 20 tyre | Porsche, 911 GT3 RS technical data, 08/2022 |
|---|---|---|
| Rear wheel | 13 J x 21 (21 in rim, 13 in wide) | Porsche, 911 GT3 RS technical data |
| Barrel just inside the lips (bead seats) | about 507 mm across | measured from the CAD |
| Depth, face lip to back lip | 264 mm | measured from the CAD |
- A rim's size in inches is the diameter of its bead seats: 20 in = 508 mm, 21 in = 533 mm
- CAD: 507 mm, 1 mm from 20 in and 26 mm short of 21 in
- Width: 10 in = 254 mm, 13 in = 330 mm. The CAD is 264 mm lip to lip, lips included, so its rim width is under 264 mm: 10 in, not 13 in
Both the diameter and the width match the 20 in front wheel, 10 J x 20.
The J width is measured between the inside faces of the lips, so a real rim is a little wider than its J number lip to lip; rounded.
Calculation How fast the front wheel turns on the car
| Front tyre | 275/35 ZR 20 | Porsche technical data |
|---|---|---|
| Top speed | 296 km/h | Porsche technical data |
- Sidewall: 35 % of 275 mm = 96.3 mm
- Tyre diameter: 508 mm + 2 × 96.3 mm = 700.5 mm, so one turn = π × 0.7005 m = 2.20 m
- 296 km/h = 82.2 m/s; 82.2 m/s / 2.20 m = 37.4 turns a second
At top speed the front wheel turns about 37 times a second, about 2,240 rpm. Rolling on its bare lips, the full-size wheel in my CAD covers 1.71 m a turn (π × 545 mm); my half-scale print, 275 mm across, covers about 0.86 m (π × 275 mm).
Nominal tyre size, ignoring tyre growth and squash under load; rounded.
