MPG decrease with new wheels

I have a 2012 PiP with 35k and just got to the point where the factory Yokos wouldn't grip anymore (2/32") so I got some 18x8 19lb wheels and some tires that were given to me (Pirelli PZero Nero All season 225/40/18 from a VW). Now, I know these are wider than stock and are not LRR but I didn't expect this much of a drop in mileage. My first tank with them (which was 93 octane by accident, I normally run 87) is about 350 miles when normally I get 420-480 on a tank. I reset trip b every fill up and the average for this tank is 45mpg. The average before was anywhere from 51-70 depending on if I had trips short enough to use only electric or not. When I drive, I can tell that it is different. It seems to slow itself down, in neutral, on all but the steepest downhills. Also, I find myself creeping into the PWR range on the HSI just to keep speed up. I may need an alignment for the new tires or just in general but it's definitely the tires, right? Would a switch to Michelin Primacy MXM4 GreenX take care of this? And how much do you think it would improve? I'm going to fill out the MPG questionnaire soon too.

 

- What fuel economy are you getting and how are you determining fuel economy? (trip computer or manual calculations) 45 via trip computer

- What fuel economy are you expecting and why? 53-63 is usually where it hovers with 15" tires

- What are the approximate outside air temps? This week 14 degrees

- How long are your trips? About 20 mins or less. But I usually get heat on most of them so the engine is mostly if not completely warmed up

How old is your 12v battery? What is the voltage reading of your 12v battery after sitting over night? (Method Here) didn't check...

Have you had your alignment checked? Any pulling or abnormal tire wear? Not enough miles on replacement tires. No alignment check

- How much of it is city vs. highway? Roughly what's the average speed in overall and and of each segment? Is there a lot of stop and go driving? Not a lot of stop and go, more highway

- What's the terrain like of your drives? (e.g. flat, gentle hills, steep hills, etc.) gentle hills with a couple steep ones

- What are your tire pressures? 40 all around on the 18s

- Is your oil overfilled? (i.e. above the full mark on the dipstick) didn't check...

- Make, model, year, engine and transmission of previous car? (e.g. 08 Honda Civic Si 2.0L 4 cylinder, manual transmission) What did you actually get on the same trips/commute? (Please give us actual numbers, not EPA ratings.) I had a 2011 Prius III that always got 46-48 and the switch to the plug in got 53-63 with combined EV-HV usage

- What region/state are you in? (if you haven't set your location) south central PA

- How are you trying to drive (e.g. trying to stay in electric only?) and how hard are you braking? I try to flow with traffic, I haven't been more spirited than normal

- What modes are you using, if any? "normal", EV, power, eco? It seems normal mode is best for me. They only seem to change throttle response

- Are you "warming up" the ICE (internal combustion engine) by letting it idle after powering on? No

- Are you driving using D or B mode? d mode

- HVAC settings? Are you using the heater, AC, auto mode, etc.? If using auto, what temp is it set to? I don't use auto because it wants to run the ac with the heat. I set floor, 70 degrees

- Are you using the factory tires and wheels? If not, please indicate tire make, model and size (e.g. Goodyear Assurance Fuel Max 185/65R15). Pirelli PZero Nero 225/40/18

- If reporting a mileage drop, did anything significant change on your car (e.g. accident, hit a curb or big pothole throwing off alignment, oil change/other maintenance/repairs, changed tires or wheels, etc.) or your commute? Changed to 18x8 19lb wheels with 225/40/18 tires

And sorry to my readers for writing a novel [/url]

 

Would I lose less with LRR 18's vs the ones I have?

 

I haven't noticed a difference driving through water or on wet roads. I guess we are sure it is the tires now. Just wondering if Michelin primacy mxm4 green-x LRR 225/45/18 tires would be as bad as these Pirelli tires are.

 

Perhaps Yokohama YK580 tires would be better even than the Michelins and obviously way ahead of the Pirelli A/S tires in the MPG department

 

LOL. The Yoko LRR tires I got with the 12 PiP were way longer wearing than the Bridgestones on the 11 III. But I'm finding 18" LRR tires and I think those would help my situation but not sure how much. The 18" tires I have were free otherwise I probably wouldn't have got wheels right now

 

For now I'll deal with it, but yes, I would like to get the LRR's soon. What is your recommendation, conti dws (not LRR but still not bad), Michelin primacy, or Yoko yk580?

 

Thanks! I did see that NineScorpion is running ~51 mpg on 18x7.5s from Drag and Conti DWS' so I know it's doable. And I think my wheels are lighter than his (hers?). Plus I'd be going with an LRR tire maybe. I really need to reign in my driving, but it was not an issue with the OE tires (because it's all engineered to put up with me).

 

Lol. That's similar to my situation as your wheels are like only 1 lb more than mine. What tires did you use?

 

Lol. I don't know if 14" wheels will fit our cars. Never looked into it. But some forged OZ 15s might be light enough. Imagine a bit of tire stretch on those like the OEM 17s