BMC left it all out on the road, finishing with the minimum four riders,
Velits, van Garderen, Dennis and Manuel Quinziato, to bury its rivals.
"It wasn't a surprise," said van Garderen.
"We definitely had respect for the other two teams here (on the podium) but we knew we had a chance. In Valkenburg (two years ago) BMC were only three seconds off winning.
"To be so close once, there's no reason not to be up there again."
The American setup rode the 57.1km UCI Road World Championship course in a time of 1hr 03min 29sec, to finish 31.84 seconds clear of silver medallists Orica-GreenEDGE, and a further three seconds clear of Omega Pharma-Quick-Step.
"We suffered out there," said Orica-GreenEDGE's Svein Tuft.
"Second again is not our favourite thing, but we gave everything we had that's for sure.
"It was definitely a lot tougher than we thought pre-riding the course. The last 10-15km was just a boxing match and it was really hard coming home."
BMC's Peter Velits was part of Omega Pharma-QuickStep's winning teams in 2012 and 2013 and has now won the event three times in a row.
"I don't think it's a secret or something, it wasn't only me in the time trial today," said Velits.
"It's the work of the whole team, everyone deserves this victory and I'm really happy I could win again, it feels really good."
The victory, which came through a rocket pace on the undulating
Ponferrada course, just shy of 54km/h, ended Omega Pharma-Quick-Step's
reign at the top of the team time trial pecking order.
The Belgian squad, led by Tony Martin, were caught out as the wind picked up in the final hour of racing. Still, despite a number of close intermediate checks, the final margin of more than 30 seconds reflected BMC's dominance on the day.
"Rain doesn't make a race easier, it doesn't make it faster. For sure it's a disadvantage to have rain, especially in the last descent, but it shouldn't be an excuse that we lost time in the final (run-in)," said Martin.
Team Sky, led by British Olympic time trial champion Bradley Wiggins, agonisingly missed out on a medal by just two seconds.
The first five days of the UCI Road World Championships will be live-streamed on the Cycling Central website, while the final two days will be broadcast on SBS ONE and streamed online.
Elite Men team time trial: 57.1km Ponferrada
1 BMC Racing Team 1hr 03min 29sec
2 Orica-GreenEDGE 0:00:31.84
3 Omega Pharma-QuickStep 0:00:35.22
4 Team Sky 0:00:37.29
5 Tinkoff-Saxo 0:00:46.59
6 Movistar Team 0:00:51.37
7 Trek Factory Racing 0:01:01.47
8 Team Giant-Shimano 0:01:26.60
9 Cannondale 0:01:28.56
10 Garmin-Sharp 0:01:44.80
11 FDJ.fr 0:02:05.08
12 Astana Pro Team 0:02:12.38
13 Team Katusha 0:02:14.35
14 Belkin Pro Cycling Team 0:02:28.16
15 Lampre-Merida 0:02:30.08
16 Rusvelo 0:02:44.81
17 Topsport Vlaanderen-Baloise 0:02:45.29
18 CCC Polsat Polkowice 0:03:36.90
19 Team Europcar 0:03:52.06
20 Ag2r-La Mondiale 0:04:05.91
21 Wanty-Group Gobert 0:04:07.49
22 Lotto Belisol 0:04:12.00
23 Caja Rural-Seguros RGA 0:04:29.70
24 Kolss Cycling Team 0:04:57.99
25 MG Kvis-Wilier 0:05:36.95
26 Rabobank Development Team 0:06:01.11
27 Adria Mobil 0:06:12.23
28 BDC Marcpol 0:06:51.56
29 Team Ecuador 0:08:08.46