Bad news you'll never get what you have hard enough If that's what you need, I assume you've raced it and know there to soft and someone else told you duro 55 to 60 ? If so and there a front runner you need more details like fresh rubber 2019 date codes ? Cured rubber 2018 or 2017 date codes ? Round cut ? NO cut ? or flat cut ?well I can already tell I don't know enough to be asking questions. These are Burris 33's that were on the kart when I bought it.