Mostert crashes, Wood flies in dramatic first Bathurst practice

Chaz Mostert has stolen the early headlines at the Repco Bathurst 1000 with a crash in Practice 1, as teammate Ryan Wood gapped the field.

It was a case of feast and famine for Walkinshaw Andretti United in a shock start to Bathurst proceedings, with Mostert's crash overshadowing Wood's superb early speed.

Wood clocked a 2:05.1029s in the final stanza, with the Kiwi's time a staggering 2.1912s quicker than the time set in the corresponding session 12 months ago.

Cars rolled out under overcast skies, but were brought in immediately as red flags flew due to a timing malfunction. Before the stoppage, reigning Supercars champion Will Brown dodged a bullet with a fast slide over Skyline.

As clouds closed in over the Mountain, Broc Feeney (2:07.3536s) and Brown (2:07.5722s) laid down solid first laps, before Wood blew them out of the water with a 2:06.4718s. Mostert slotted into second, forming a WAU 1-2.

Wood lowered the benchmark to a 2:06.3767s, with Mostert (2:06.5908s) and David Reynolds (2:06.6213s) behind as cars completed their first runs.

Light rain began to fall at the halfway mark as teams cycled through their programs, with the balance of the field returning to pit lane. It didn't stop Feeney, Payne and De Pasquale improving, with the championship leader slashing Wood's lead to 0.139s.

It was a vastly more dramatic fate for two-time Bathurst winner Mostert, though, who locked up heavily into Griffins Bend and buried his #25 Mobil 1 Optus Mustang into the barriers.

"I just went slightly later than what I did the run before, but for whatever reason the brake just wouldn't release," Mostert explained.

"I had a small lock, but I don't know, it felt like it skated. Obviously in that situation you keep going down the gears, you keep trying to wash off as much speed as possible, but even on the pump of the brake, it just wouldn't release.

"I don't know if I just found one random crack of water in a line or something like that, it just took no speed off."

Payne soared to third after the session resumed with a 2:06.5180s, and threatened to go even faster before coming into the lane. In response, Feeney powered into the 2:05s with a 2:05.9879s, with Brown forming a Triple Eight 1-2.

Armed with new tyres, Wood lit up the time sheets in the closing minutes. The New Zealander went quickest in all three sectors to lay down a 2:05.3199s, which was nearly 0.7s up the road.

Wood marched on and went faster in the first and second sectors, nailing a 2:05.1029s. Payne improved to a 2:05.9362s, but was a whopping 0.833s behind his countryman.

As Allen split the New Zealanders, Payne turned in a purple first sector, only to lose time and come back into the lane. All the while, De Pasquale jumped ahead of the Penrite Fords, but was still 0.642s off Wood's pace. The Team 18 driver improved to a 2:05.5265s, but Wood was unmoved.

Allen, Payne, Feeney, Cooper Murray, Brown, Andre Heimgartner, Reynolds and Jack Le Brocq rounded out the top 10.

Co-drivers will take to the track for a dedicated session at 4:50pm AEDT to round out Thursday's action.