Pirelli Cinturato P7 (P7C2) vs Michelin e.Primacy — Compared

“Got the Michelin e.Primacys today - what an improvement! 2019 owner, bought a little over 2 years and 34k miles ago. Have always had the OG Energy Savers and was never happy with their performance as far as grip. After needing my second set of tires in 2 years I wanted something new and knew these were coming because of the new Bolt. Stretched as long as I could on my previous set until I had a close call last week. These popped up at the local tire shop, and also took the chance to swap to the Cruze Eco rims. First impressions (note these are the same size as the factory Energy Savers): Smoother Ride on Rough Roads WAAAAY Less Road Noise, Especially at Higher Speeds Dry Grip is Much, Much Better (not sports car, but if the Energy Savers were 2/10s these are 7/10s) Efficiency Seems Similar (needs more testing, only have ~30 miles right now) Read more”

“Seen a couple of Q8 e-tron owners say the Michelin e.Primacy gives a small bump in range and lower road noise compared to the OEM Continental EcoContact, but wet and winter grip can feel a bit less confidence inspiring.”

“I got a bit carried away and looked up the tyre label and Michelin's numbers for rolling resistance, and the weight of a BMW i3 . Short answer: save 6%. Here's the result as a table. RR C kg/t or N/kN mass tonnes Drag N or kJ/km Wh/km Wh/mile unit values 1 1.00 9.81 2.72 4.38 E.Primacy 5.5 1.7 92 25 41 Car tyres (C1) fuel class A 6.5 1.7 108 30 48 Car tyres (C1) fuel class B 7.7 1.7 128 36 57 Car tyres (C1) fuel class C 9.0 1.7 150 42 67 Car tyres (C1) fuel class D 10.5 1.7 175 49 78 class E is anything worse than D The total energy per mile for tyre rolling resistance of a 1.7 ton vehicle running on bottom-of-the-band class B tyres is about 57 Wh/mile, or about 22% of EVDB's broad figure for the i3's total consumption 261 Wh/mile. With Michelin E.Primacy tyres (rolling resistance from Michelin's publicity), that should drop to 41 Wh/mile for the tyres, or a saving of 16 Wh/mile, a range improvement of about 6%, or from 3.8 miles/kWh to 4.1 miles/kWh. Nice to have, but not dramatic. It does show that fuel label class C, D or E tyres are worth avoiding if you can fit better.”