The penultimate stage of the race saw the riders tackle a flat 24km out-and-back course that included some technical sections, but with the main issues being that it took place at more than 2,000m above sea level along the shores of Big Bear Lake.
Among the early starters, Italian Filippo Ganna (UAE Team Emirates) was the fastest, setting a time of 28-48 which stood for nearly an hour until it was beaten by 21 seconds by Jon Dibben (Team Sky), with the 23-year-old neo-pro pulling out a strong ride that would be enough for to give him the stage win.
Dibben’s time would not be touched by any of the general classification, but Brent Bookwalter (BMC Racing), sixth in GC going into the stage, put in a strong performance to knock Ganna down the standings, finishing in a time that was just seven seconds slower than Dibben.
Cannondale-Drapac’s Andrew Talansky, winner of Thursday’s summit finish to Mount Baldy, had been expected to perform well, and delivered with a time 16 seconds behind Dibben that would eventually be good enough for third on the stage.
Less expected was the performance of George Bennett, with the New Zealander delivering one of the best time trials of his career to lose just two seconds to Talansky.
However there was no such good news for fans of race leader Rafal Majka, who despite looking smooth throughout his ride, finished in 22nd place, dropping nearly a minute.
Ian Boswell (Team Sky), third overall coming into the stage, also finished on the same time as Majka, results that meant Majka dropped to second behind Bennett, while Boswell dropped to fifth.
The 2017 Tour of California concludes on Saturday with a 125km stage from Mountain High to Pasadena.
Tour of California 2017, stage six: Big Bear Lake to Bike Bear Lake (24km, ITT)
1. Jonathan Dibben (GBr) Team Sky, in 28-27
2. Brent Bookwalter (USA) BMC Racing, at 7 secs
3. Andrew Talansky (USA) Cannondale-Drapac, at 16 secs
4. George Bennett (NZl) LottoNl-Jumbo, at 18 secs
5. Filippo Ganna (Ita) UAE Team Emirates, at 21 secs
6. Maximilian Schachmann (Ger) Quick-Step Floors, at 21 secs
7. Peter Sagan (Svk) Bora-Hansgrohe, at 23 secs
8. Maciej Bodnar (Pol) Bora-Hansgrohe, at 23 secs
9. Martin Elmiger (Sui) BMC Racing, at 25 secs
10. Nils Politt (Ger) Katusha-Alpecin, at 27 secs
General classification after stage six
1. George Bennett (Nzl) LottoNL-Jumbo, in 20-16-38
2. Rafal Majka (Pol) Bora-Hansgrohe, at 35 secs
3. Andrew Talansky (USA) Cannondale Drapac, at 36 secs
4. Brent Bookwalter (USA) BMC Racing, at 45 secs
5. Ian Boswell (USA) Team Sky, at 1-00
6. Vegard Stake Laengen (Nor) UAE Team Emirates, at 1-54
7. Tao Geoghegan Hart (GBr) Team Sky, at 2-12
8. Sam Oomen (Ned) Team Sunweb, at 2-15
9. Lachlan Morton (Aue) Dimension Data, at 2-20
10. Haimar Zubeldia (Esp) Trek-Segafredo, at 3-14