Results / Kit
Four sleeve fabrics.
The question
Harrowgate had four fabrics for the upper arm of a new suit. Textured fabrics can make the air cling to a round arm for longer and shrink its wake, but only in a band of speeds. They wanted to know which fabric, at which speed.
Fabrics
4
Speeds
40–50km/h
Best vs worst, 50 km/h
15W
Runs, each fabric twice per speed
24
The results
| Fabric | 40 km/h | 45 km/h | 50 km/h |
|---|---|---|---|
| 1 · Smooth lycra | 0.000 | 0.000 | 0.000 |
| 2 · Fine rib | −0.002 | −0.004 | −0.005 |
| 3 · Dimpled | +0.001 | −0.005 | −0.009 |
| 4 · Coarse rib | +0.004 | +0.002 | −0.001 |
Differences in CdA (m²) from the smooth fabric; negative is faster. At 50 km/h, 0.009 m² between fabrics 3 and 1 is 15 W (½ × 1.225 × 0.009 × 13.89³).
What they did
The dimpled fabric was slower than smooth lycra at 40 km/h and the fastest by 50. That is the band the fabric works in. Harrowgate used it on their time-trial suit, for riders who average 45 km/h and up, and the fine rib on their road suit, where it never lost at any speed we tested.