How much would a wattage saving of 8 watts improve my average speed? I've current hot Pirelli Cinturato velo tubeless tyres fitted to my 2017 Felt VR3 with a rolling resistance of 17 Watts at 100 psi. I'm thinking of changing them to some gp 5000 tubeless with a rolling resistance of 8.9 Watts at 100 psi. With the Pirelli it's a real struggle get an average speed above 14.2 mph I've managed 14.7 a couple of times but it's bloody hard work. These low averages are despite achieving a maximum training effect of 5 regularly its always between 4.5 and 5 so I think I should be getting much higher averages for the effort I'm putting in?