@MrOrbea The Gain doesn't have a thru axle in the rear since it has the u-shaped dropouts used for quick release axles. The Kickr supplies both a thru axle and quick release skewer, you have to use the quick release skewer to attach the Gain to the Kickr, a thru axle won't work because of your style dropouts. The Saris H3 should be the same and give you either option, you'd need to use the quick release skewer and any spacers to get the proper width since not all bikes are the same (it should come with the spacers as well.) Hope that helps.