Head to head
Black Inc Forty FivevsBontrager Aeolus RSL 51
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
Black Inc Forty FiveBontrager Aeolus RSL 51
- Depth
- 6 mm apart
- 45 vs 51 mm
- External
- 1 mm apart
- 30 vs 31 mm
- Internal
- 0.5 mm apart
- 22.5 vs 23 mm
- Claimed weight
- 65 g apart
- 1,385 vs 1,450 g
- UK RRP
- £200 apart
- £2,000 vs £2,200
Rim depth
45 mm
51 mm
6 mm apart. Deeper is faster on the flat; shallower is calmer in crosswind and lighter uphill. Neither is simply better.
Internal width
22.5 mm
23 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
30 mm
31 mm
Governs how the rim and tyre meet the air, and frame clearance.
Black Inc
Forty Five
RRP £2,000
UCI mass-start road
Eligible — Eligible on the rules we assess
Bontrager
Aeolus RSL 51
RRP £2,200
UCI mass-start road
Eligible — Eligible on the rules we assess