The UCI reversed its policy of banning mixed wheelsizes late last year for DH and Enduro. Within weeks, several teams experimented pairing a 29" front wheel with a 27.5" rear wheel, notably, Specialized, GT, and Polygon. Neko Mullaly tested a reverse mullet build on his Tues, 2 years after trying it out on his old Gambler "Frankenbike".
In recent times, there have been a few intrepid manufacturers who actually designed and released 97.5 gravity bikes, like Foes and Liteville. Reviews were generally positive but no discernible data has been released comparing it to bikes with same-sized wheels.
Is the 97.5 bike a true game-changer? Will it only fit specific riders and/or riding styles? Will a 97.5 bike ever win the World Cup overall or the EWS?