Indy 500 practice: Marco Andretti fastest in Wednesday session

Andretti's #98 Andretti-Herta Autosport machine turned a total of 117 laps but his best came at around the halfway point of his day, a 227.053mph lap that made him the only driver to breach that barrier.

Chip Ganassi Racing-Honda's Scott Dixon was second fastest with a 226.329mph lap, while in the closing 40 minutes, last year's winner Takuma Sato slotted Rahal Letterman Lanigan Racing ahead of Schmidt Peterson's rookie Robert Wickens as they claimed third and fourth.

Charlie Kimball did a great job to clock the fifth fastest tome for Carlin, which is entering the Indy 500 for the first time this year.

Tony Kanaan brought out the only yellow flag that wasn't for a track inspection or debris when a throttle sensor failed, but he was able to remain firmly in the top 10, and his best no-tow speed of 223.048 kept him top of the 'NT' charts.

The top one-off Indy entry was Oriol Servia in the Scuderia Corsa-Rahal Letterman Lanigan Racing-Honda, grabbing ninth place ahead of another Indy-only driver, Sage Karam with Dreyer & Reinbold.

The Penske quartet had a relatively subdued day judging by lap speeds alone, but Josef Newgarden (11th), Helio Castroneves (18th), Will Power (21st) and Simon Pagenaud (24th) did a lot of running in convoy in the mid-afternoon to gauge aero effect.

James Hinchcliffe turned the most laps (129) and only one car (Matheus Leist) did fewer than 60.

Wednesday practice times