Whilst we all love the Challenge Grifo Open Pro [the one with the skin wall] for it's grip and speed in all but the muddiest of conditions, there's one thing it cannot do, and that's run Tubeless!Although I have run them tubeless successfully for a 'while', they are not a viable Tubeless option and there are much better alternatives, including the 120tpi Grifo. The problem with the Open Pro design for Tubeless setups is that they are incredibly flexible and they can roll off the rim with some combinations of rim, tape and pressure. As such I no longer recommend the Open Pro Grifo for tubeless with any combination of rim, pressure etc. If you want to run Tubeless and want the Grifo tread then you should chose the 60tpi or 120tpi version produced by Challenge.
The 120Tpi version is now standard kit on Helen Wyman's signature bike from Kona and it's set up Tubeless from the off.
The RRP of the 120tpi is £35