Sumitomo HTR Z doesn't seem right. From the PDF on the right side of Sumitomo Performance Tires: HTR Z, there are none of size 215/45/17. BTW, I did find this http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=121 and http://www.tirerack.com/tires/tests/chartDisplay.jsp?ttid=121. You can see there was a 3.8 mpg difference on a 2nd gen Prius between the best and the worst they tested. The Goodyear Integrity are the stock tires that come on non-Touring 2nd gens. All were 185/65R15 size.
See the 1st PDF of http://priuschat.com/forums/gen-ii-...angauge-best-threads-mileage-improvement.html. S4 == Stage 4. (I do have a http://www.scangauge.com/, BTW. )
Hopefully someone can chime in about the revs per mile as well as their rolling resistance. My quick Googling didn't turn up any RR ratings, but there's no mention of LRR on Tirerack or Sumitomo Performance Tires: HTR Z II. Your tire pressures might be too low for that tire. http://www.sumitomotire.com/assets/products/performance/htrz2_htrz_sm.pdf and your link say max inflation pressure is 51 psi vs. 44 psi of the stock Goodyear Integrity. People here frequently run the stock Integrities at 40+ psi.
Not really. But, I moved away from my former much longer commute that yielded me much better mileage (in CA) to a colder state w/a VERY short city commute within a few months after getting SG. :/ It DOES help me know for sure when the ICE is turning or not (sometimes my assumptions were wrong). I also always leave up FWT (Fahrenheit Water Temp) so I can tell when the ICE is too cold and will kick on to provide cabin heat. If I didn't have it, I'd either unnecessarily run the ICE to provide cabin heat or freeze needlessly. I think if I didn't never had SG, my mileage would be a tad worse.
Hi tan03. Re the "stage 4" thing you might find this useful : http://www.techno-fandom.org/~hobbit/cars/five-stages.txt
Yes, intially by about ~6 mpg, but it also slowed me down a bit and now by ~10 mpg, but it has increased my traveling time by about 10%. Without a SG, to force S4, you need to warm up the engine (highway driving is best, ~10 minutes will do) come to a complete stop > put the car in P > press the gas pedal to start the engine > lift the pedal and wait for ~7 seconds for the engine to shut off. From then on, every time you don't require a lot of gas from the car AND your HV battery's charge is 5 bars of more the engine will turn itself off and you will be able to glide with electric energy without the engine spinning. That saves a lot in the city. Highway savings are more complicated. Essentially you need to accelerate moderately and use the "yellow arrow condition" when you go downhill. IF there are no hills you need to be using as much gasoline so that your MPH will be equal to or 1.2x your mpg. Have a look at the first page thread referring to 66-68 mph pulse and glide vs SHM.
Interesting... I'll have to look into that. I always ignored pulse and glide above 41 mph. The OP mentioned 70-75 mph on the highway which isn't surprising given that people do drive fast in LA (and pretty much have to unless you want stay in the rightmost lane). I found SHM utterly unsuitable for me at slightly lower speeds when I was living in Nor Cal. (http://priuschat.com/forums/gen-ii-...y-mode-alternative-65-75-mph-range-hints.html) While this might not solve the OP's immediate apparent mileage reduction due to unknown causes (it might just be weather, winter gas, along w/his shorter drives and different route), I really think the OP should go back to the 15" wheels and find a set of tires that Priuschatters have found have low rolling resistance (other than the crap stock GY Integrities). He should see some improvement from that alone.
