Michelin Cross Climate 2

[MichaelC]

I now have 1 month of drive time on the Cross Climate 2 tires I got with my aftermarket 19" wheels (see Aftermarket wheels? thread for details).
Overall, I am very happy with their traction (better than the stock Continentals) and comfort/noise (equivalent to the stock Continentals). I have seen an efficiency hit of 0.4 mi/kWh on average, as shown in the summaries below:

September was all on the stock 19" wheels with Continental tires, and October was all on the aftermarket 19" wheels with Michelin tires.

My longest road trip to-date was in September (776 miles round trip), whereas my longest trip in October was only 97 miles. Temperatures have also cooled down a lot recently, which has had an impact--but I don't think enough to really skew these results.

I will take much longer road trip in mid-November (Kansas City to Baltimore and back), which will give me significantly more experience with these tires.

 

[teslarati97]

Interesting. I am currently getting 2.7mi/kWh on my winter tires and 19" kaliedo spoke wheels. Temperatures are already below 32F overnight.

 

[MichaelC]

We got our first freeze last night/this morning but have at least one more roller-coaster week of warmer temperatures ahead. Your previous reports on cold weather efficiency losses has me expecting lower numbers once the local temperatures stay consistently cold.

I plan to post monthly updates here so all seasons are represented. Granted, the more open wheel design will reduce efficiency a bit at higher speeds, so results may vary for those who use them on their stock wheels.

I'll be curious to see how well the built-in navigation deals with temperature changes on my upcoming road trip (which will also include some big elevation changes).

 

[teslarati97]

While not totally scientific, I have seen some efficiency differences between a garaged EV and cold soaked one. There's probably an operating temperature range for the battery and motors as well as the heat pump vs resistive heating temperatures. Crossover point is somewhere around 14F.

 

[MichaelC]

Road trip report: Kansas City area to Baltimore
Before I left home, I set the tire pressures to match the placard at my expected average temperature for this trip (50F). While the TPMS display confirmed I met my target, the dynamic "recommended" pressures consistently suggested the front tires should be 2PSI higher and the rear 1PSI higher. I thought about adjusting tire pressures accordingly in a hotel parking lot, but the built-in tire pressure gauge of the MINI-included tire inflator is...not set up for that kind of accuracy. Shoulda packed my own gauge - lesson learned.

Here are the efficiency numbers reported by the 'My Trips' feature in the MINI app:

• "Flat" interstate driving (KC to St. Louis) @ 70mph (with some construction zones) in ~50F with cross-wind: 2.9 mi/kWh
• "Hilly" 2-lane highway driving (rural Indiana) @ 55-65mph in ~40F: 3.6 mi/kWh
• "Mountain" interstate driving (Lexington, KY to Morgantown, WV) @ 65-70mph (with some construction zones) in ~54F: 3 mi/kWh
• "Mountain" interstate + 2-lane driving with a cold battery (Morgantown, WV to Frostburg, MD) in ~44F: 2.8 mi/kWh
• "Mountain" interstate + 2-lane driving after warming up (Frostburg, MD to Middletown, MD) in ~50F: 3.1 mi/kWh
• "Mountain" interstate + urban driving (Middletown, MD to hotel in downtown Baltimore) in ~52F: 3.2 mi/kWh

All of these were in dry conditions. Looks like I should go through some rain on the return trip.

EDIT: Also, all were done in Green mode with climate set to 69F (though I switched back to Core once I got into city traffic in Baltimore).

I am pleased to report that the built-in navigation did a great job estimating arrival SOC for each destination and charging stop. It updates the estimate along the route, but was consistently within 5% of the original estimate upon arrival. Note that I set the cruise control to the posted speed limit, so your mileage may vary if you like to add a couple mph to offset the speedometer calibration.

Beware that if you prefer "Out Of Spec" style charger arrivals, the system is very aggressive about warning you when your SOC is getting low--even if you're navigating to a charger and have more than enough range to get to it. And those warnings tend to cover up the 'next turn' prompt on the center display (thankfully, there's enough redundancy with the HUD and the map + camera view of the turn). I did this a couple times on the "flat" leg and saw warnings at:

• 40 miles of range remaining (typically 21% SOC)
• 25 miles of range remaining (typically 13% SOC)
• Warning that the battery is at a low SOC when you turn the vehicle off, and recommendation to charge it immediately.

 

[teslarati97]

That's interesting how your lowest efficiency was from the cold HV battery. Unlike many other OEMS, the BMW Gen5 HV battery modules are designed to be repairable. My understanding is that the coolant line runs down the middle and the modules are cooled from the sides (with exception of the end cells getting the most surface area). This would certainly drive up the manufacturing costs instead of the cost saving thermal interface and pouch cell method.

I'm going to have to keep that in mind for road tripping as well. It would also really be nice for supercharger access as the only other DCFC options are 50kW. Seeing 2.8mi/kWh in 44F is a bit concerning for me, because I maybe want to do a winter road trip at 5F!

 

[MichaelC]

Yeah, I was surprised to see such a low efficiency number even though the last several miles of that leg were at pretty low speeds - though with some major elevation changes. A contributing factor is that I was navigating to the site hosting a 62.5 kW ChargePoint DCFC, but not navigating to the actual charger - so the battery was not preconditioning. I did this intentionally since I knew it was a lower-speed charger and planned to eat lunch there, so didn't mind lower charging speeds.

Also, I edited my post above to note that those were all in Green mode. It would be nice to see the break-out of how the power is being used, but I suspect the largest energy savings in Green mode is that it leans on the heat pump more versus the other modes.

Speaking of Supercharger access: I noticed that ABRP has started preferring "NACS partner" Tesla sites for as many charging stops as it can find, even though I haven't seen any announcements yet from BMW/MINI about gaining access...and I don't even have an adapter, anyway. Have they jumped the gun? Or do they need to add a selection for whether my U25 was built with a NACS port or not? Ah; I dug around in the settings and found the option for "Type of chargers" and selected "CCS". That seems to have cleared it up. Maybe this is a new setting?

 

[teslarati97]

Hard to say about green mode, because I can still hit 3.1mi/kWh in Core or Trail mode on a very sunny day. Probably the heated steering wheel and seats are killing the overall efficiency for me.

Gen5 motors are less efficient a lower speeds as externally excited motors (no permanent magnets) because of the electrical requirements. However, the opposite is true at higher speeds because the lack of permanent magnets reduces the interference. Not a big deal for me as I will just use the F56 BEV for urban driving!

The NACS adapter option is a newer feature for ABRP, but it's on all North American brands. The option doesn't show up for brands like BYD or Renault.