Dixon fastest on day two of Indy 500 practice as Alonso crashes

Five-time IndyCar champion Dixon clocked a 226.102mph lap in the final hour of the day's running, around 0.4mph ahead of Takuma Sato's top time from the morning, while Marco Andretti slotted his Andretti Herta Autosport machine into third to make it a Honda 1-2-3.

Conor Daly again looked strong for Ed Carpenter Racing, landing P4 - the last of the cars under the 40s barrier and the top Chevrolet runner - while fastest rookie was Alex Palou's Dale Coyne Racing with Team Goh entry in fifth.

Colton Herta took sixth - and second fastest speed set without the aid of a tow, beaten only by Jack Harvey in the Meyer Shank Racing-Honda, which broke into the 222mph zone.

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The earlier speed of Charlie Kimball (A.J. Foyt Racing-Chevrolet) kept him seventh, as improvements became scarce as temperatures climbed and speeds dropped.

But one of the major talking points was Alonso's shunt in the final hour.

He was trailing a crocodile of cars with barely 45 minutes left to run in the 6hr30min day two practice, when he went over the concrete strip at the apex of Turn 4.

The #66 Arrow McLaren SP-Chevrolet became unsettled and slid high and hard into the outside wall before bouncing off, spinning through 180 degrees and sliding backwards down pitlane.

Alonso, who is due to make his second start in the Indy 500 next week, was checked and cleared by medical staff.

Alonso tweeted: "126 laps today and good day in general, until last hour that I made a mistake and touch the wall."

Despite the shunt, he was still fastest Arrow McLaren SP driver, although he was only a couple of spots ahead of rookie Oliver Askew.

The pair were separated by another Coyne car, the 'extra' entry - in partnership with Rick Ware Racing/Byrd/Belardi - driven by James Davison.

Team Penske-Chevrolet's drivers were only 16th, 18th, 23rd and 27th.

Felix Rosenqvist (Ganassi) and Dalton Kellett (Foyt) turned the most laps of the day at 141 each.

The cars' twin BorgWarner turbos will now be increased from 1.3-bar to 1.5-bar for Friday's practice session, which will yield 80-90 extra horsepower.

This is in preparation for qualifying weekend, in which the cars run with this increased level of power and are trimmed out aerodynamically for the four-lap runs that set the grid.

Day 2 practice result