Haas's Romain Grosjean worked hard and braked hard all day in Bahrain as his sampled Carbone Industrie's product in the team's quest for more consistent braking power.
Dogged with braking issues since last summer which weakened his confidence, the French driver admitted that CI's product already felt better compared to Brembo's offering despite the fact that the latter had improved greatly lately.
"We still have a lot of work to do around them and see the performance, but it feels better, as it was last year,” explained Grosjean after testing.
"Otherwise it's quite similar. We just need to see if we can actually make it work with all our mapping."
If further testing validates Carbone's brakes, Haas could switch suppliers sooner rather than later according to Grosjean.
"I think it could come for Russia. It's all ready," he said.
"But only if we're confident that we're going to start Russia without a hitch, as you cannot miss FP1 and part of FP2 because you're not right on mapping.
"We've collected a lot of data today and I think the guys are going to be working on that."
Kevin Magnussen's day tomorrow could ultimately sway a choice which is rendered more complicated by Brembo's recent improvement.
"With the Brembo we have the baseline. We know how it works. On the other one, we've worked for an afternoon but it's not a lot.
"We did seven or eight runs. The time to change the brake balance, the time to change the mapping and get it more or less where you want.
"I think Kevin is going to keep working tomorrow [Wednesday] and then we're going to decide."
GALLERY: All the action from the Day 1 in-season testing at Bahrain
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