Baku, Azerbaijan - Baku's inaugural grand prix is under a cloud due to a worrying problem with kerbs at the brand new street circuit.
GP2 qualifying was postponed on Friday, with Germany's Auto Motor und Sport reporting that 90% of the F1 cars in opening practice suffered damage to their tyres.
Loose kerbs
With the subsequent GP2 session red-flagged, Charlie Whiting and his delegation inspected the kerbs and found them loose and with sharp edges.
At the unprecedentedly-fast, wall-lined street track with small run-off zones, the risk of failing tyres is a major problem.
Sauber's Felipe Nasr: "I got my puncture on the lap Ricciardo crashed.
"When I wanted to get back on track they told me the left rear tyre was damaged and we had no more," added the Brazilian.