Head to head
Shimano Ultegra WH-R8170 C36vsZipp 303 Firecrest
Both sections drawn to one scale, from each maker's published geometry. The differences you can see in the drawing are the differences that exist.
vs
Fig. — rim sections, one scale
Shimano Ultegra WH-R8170 C36Zipp 303 Firecrest
- Depth
- 4 mm apart
- 36 vs 40 mm
- External
- 2 mm apart
- 28 vs 30 mm
- Internal
- 4 mm apart
- 21 vs 25 mm
- Claimed weight
- 138 g apart
- 1,488 vs 1,350 g
- UK RRP
- £400 apart
- £1,400 vs £1,800
Rim depth
36 mm
40 mm
4 mm apart. Deeper is faster on the flat; shallower is calmer in crosswind and lighter uphill. Neither is simply better.
Internal width
21 mm
25 mm
The wider rim is built around a wider tyre. Match this to the tyre you actually run, not to the bigger number.
External width
28 mm
30 mm
Governs how the rim and tyre meet the air, and frame clearance.
Shimano
Ultegra WH-R8170 C36
RRP £1,400
UCI mass-start road
Eligible — Eligible on the rules we assess
Zipp
303 Firecrest
RRP £1,800
UCI mass-start road
Eligible — Eligible on rim height; tyre choice is restricted