Is Rio Tinto (ASX:RIO) share price a better buy than BHP (ASX:BHP) share price?

ASX iron ore stocks are surging and could be heading higher. The question is whether the Rio Tinto Limited (ASX: RIO) share price or BHP Group Ltd (ASX: BHP) share price is the better buy?

Australia’s largest listed iron ore producers have each surged between 4% and 5% in after lunch trade as they are likely to be upgraded by analysts.

A jump in the iron ore price after Brazilian rival Vale SA downgraded its 2020 and 2021 production guidance is driving these stocks higher.

The big rally among ASX iron ore miners is largely responsible for the 0.5% increase in the S&P/ASX 200 Index (Index:^AXJO) today.

BHP share price vs. Rio Tinto share price

The best way to gain exposure to this thematic is to buy a basket of ASX iron ore…