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Discussion Starter · #1 ·
I am having a mild crisis in efficiency on my Volt after new tires.

I bought my 2012 Volt in 5/2012. Since I bought it, I saw efficiencies during the best weather (read off of the kWh counter) of about 5 miles/kWh at the best, 4.5+ miles/kWh on pretty good days and not rarely, 4.0-4.5 miles/kWh as my average and 4.0 miles/kWh on less good days. Less than 4 was a bad day.

My AER was usually around 40-45. I hit 50 miles last fall as my best ever. I see kWh used totals for a full battery on the kWh counter at a low of about 9.3 kWh when I park the car in the 1-3 kWh or 7-9 kWh used range, 9.6 or 9.7 kWh if I drive it straight to depletion and 9.8-10.2 if I park the car in the 4-6 kWh used range before depleting it.

I had my tires changed at 44,500 miles. I decided to go with the original tire type to keep my efficiency as high as possible. I had 4 new Goodyear Assurance Fuel Max tires 215/55 R17 put on at that time on 8/2/17.

I am currently at about 48,000 miles. Since the new tires I have seen a pretty profound drop in my efficiency. Instead of 4.0-4.5 miles per kWh, I now get about 3.5 miles per kWh. It is a drop of about 20%. I am getting about 30-35 miles for a full battery now. The very best I have been able to achieve is 4.0 miles/kWh and about 40 miles on a battery charge. I still managed to get 10.2 kWh out of the battery recently, so I don’t believe it to be a battery capacity issue.

I chose the Fuel Max tires so I would not have this problem. I expected some loss in efficiency with new tires, but this is way more than I would have thought. It also has not shown any signs of improving in the 3500 miles since the new tires were put on. When my Volt was new, it had new Fuel Max tires on it, and my efficiency was great at that time, so something is different.

Does anyone have any suggestions about what could be going on? Maybe some part of it is the new tread, but I would think it would start to improve by now. Could there be some alignment issue related to how the new tires were put on? Are new Fuel Max tires possibly much heavier than the tires they put stock on the Volt which maybe were specially designed for the Volt? Is there any possibility that battery degradation shows up in this way, with decreased efficiency? (that explanation doesn’t sound right to me.)
 

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There are more than one Goodyear Assurance Fuel Max tire version. I suspect the ones you got are heavier (perhaps different thread pattern and rubber compound?).
 

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Brand new tires and colder weather,, at the same time.

Take two aspirin and report back in the spring.

Try a few runs with the tires at a higher pressure too.
 

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I think this is purely a tire issue. New tires will always be worse because they have max tread depth and weight. 3K miles is not enough to counteract that. There will be some initial break-in, but it will take tens of thousands of miles to wear the tread down. Also, there are maybe 3-4 versions of the Goodyear fuel max tires. The OEM's had an unusually narrow tread width. It is likely you have a wider tread version (even in the same numerical size). The efficiency numbers you are getting now are very much in line with my car. I do not think there is anything wrong with the car. The OEM tires were efficient, but also prone to blowouts and flats, so you can choose to think of it as good you do not have the OEMs any more. Your true increase in gas consumption will probably not be very big.
 

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Discussion Starter · #6 ·
Thanks, guys. This made me feel better. You are probably right that the Volt OEM's were different than usual Fuel Max tires and were especially efficient and the Fuel Max tires I got are probably heavier with less efficient tread pattern. So the difference probably feels especially bad. Knowing this, maybe if I could do it again I wouldn't bother with the Fuel Max since they don't seem to have bought me anything as far as efficiency and I could have gotten a better quality tire and gotten the same efficiency penalty.
 

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Thanks, guys. This made me feel better. You are probably right that the Volt OEM's were different than usual Fuel Max tires and were especially efficient and the Fuel Max tires I got are probably heavier with less efficient tread pattern. So the difference probably feels especially bad. Knowing this, maybe if I could do it again I wouldn't bother with the Fuel Max since they don't seem to have bought me anything as far as efficiency and I could have gotten a better quality tire and gotten the same efficiency penalty.
Even if you got the same exact tires, you would have still suffered some efficiency loss as worn tires with 40k miles on them would have less grip than brand new tires. For you, it is likely it was a double whammy of new AND higher rolling resistance tires.

I ended up replacing my Goodyear OEM's with Bridgestone Driveguards. I had to sacrifice 15% or so in efficiency, but now I don't have to worry about getting stranded with a flat. And my commute is still easily covered on battery only even with the Driveguards.
 

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Tire Rack .com has 2 Goodyear products in 215/55/17 listed. One had a advertised tread width of 6.5" the other shows 8.3". You got the wide one. With my 2011 at 106,500 on the odometer I've been through this issue. Tread width has a major impact on range and fuel mileage. I am now running Michelin Primacy MXV4's newer ones still affect range, but no where near as bad as the wide Goodyears I was running for awhile.
 

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Brand new tires and colder weather,, at the same time.

Take two aspirin and report back in the spring.

Try a few runs with the tires at a higher pressure too.
Joshili is in Dallas/Ft Worth area according to profile, so my guess is winter range will be much better than summer range ;)
 

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Have you checked you tire pressure, You are safe on those up to 50 PSI is max. I would put them @ 45 PSI and if you get better range.
 

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Discussion Starter · #11 ·
Yes. I am very mindful of my tire pressures. I run about 42 psi. It is not all weather related. There have been several perfect days here with temps in the low 70's where I didn't run any ac/heat and drove gently and still had disappointing efficiency.

Discount tire and Goodyear are both clueless. They can't tell me any details of my particular tire other than Discount Tire telling me they have 2 versions of the tire available, GM OEM version and a version that is not GM OEM. They gave me the non-GM OEM version. Nobody can tell me what the difference is, though. I am sure Discount Tire would let me change tires if I wanted. What do you think? Should I just try a different type of tire? Is there one that people have had good luck with on the efficiency standpoint? I originally was going to get Michilen Energy Savers but they don't come in the right size.
 

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Go to tirerack.com web site and find the 215/55/17 Goodyear Assurance Fuel Max listings. When you open the full product description at the bottom of the page you will see a "spec" link. You can open this and see the weight, cross section, tread width etc. I think they should remove your wide tires and give you the narrow OEM ones. After all you shopped for an exact OEM tire and got something else through no fault of your own.
 

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Yes, I suspect you have the wider version, which is also heavier. So triple whammy on range: Wider, heavier, new tread.
 

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Discussion Starter · #14 ·
So I have confirmed that the Fuel Max tires given to me were the non-GM OM version. I cannot get many specifics about the differences, but one spec that is clearly different is the weight. The OM tires are 20 lbs. The version I got are 25 lbs. That's not insignificant. Goodyear also apparently doesn't make the GM OM tires anymore. They are being nice at DT and offering to let me switch out for another tire if I want. I haven't decided on that. I would if I knew of a tire that would give me back some range, but it is unclear to me that there is such a tire.
 

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The GM-oem tires have a crest molded in the sidewall that says TPC 1406. That's the GM standard.
 

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Discussion Starter · #17 ·
Well, the Michelin Premier AS 96H seems to have some good reviews in past postings in this forum. They are 22 lbs which is better than the 25 lbs of the current tire. The posts of the Volt drivers seemed to report an initial 5 mile or so loss in range that recovered after about 6 months. 5 miles loss would be less than I have lost. (I estimate about 7-8 miles AER lost.) They seem to have those in stock. I may try those.
 

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I know this is an old thread, anyone been able to get the OEM spec GY Assurance Fuel Max? Just ordered these and apparently the only version left is heavier and a lot wider (8.9” if I am reading the spec correctly).
 

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I know this is an old thread, anyone been able to get the OEM spec GY Assurance Fuel Max? Just ordered these and apparently the only version left is heavier and a lot wider (8.9” if I am reading the spec correctly).
I replaced my 2012 Volt’s OEM tires in 2018 with the 22 pound version of the Goodyear Assurance tires. The Goodyear website then listed three versions of the Fuel Max tires. All of the stock numbers are 738 XXX 571. The OEM Goodyear Assurance Fuel Max tires (XXX=340), no longer available, weighed 20 pounds. After some effort, I was able to learn that the version where XXX=548 weighs 22 pounds, and the version where XXX=735 weighs 25 pounds. It appears the two available versions differ in tread width and/or depth, and it seems to me a wider tire or deeper tread depth would indicate a greater amount of tire material, i.e., a heavier tire.

My "benchmark" for a fixed distance driven using a fixed quantity of battery power was the drive from my home when fully charged to a grocery store some 3.9 miles from home at a slightly lower elevation. For quite some time, I could arrive at the store with the energy usage display reading 0.6 kWh Used. With the new tires, that crept up to 0.7 and 0.8 kWh Used. That translated into a proportional decrease in the full charge range (although I rarely drive that far). I suspected the difference was in part because the tires were new, but also because they were heavier than the OEM version. Now, some 2+ years later, I can make the same trip frequently seeing the original 0.6 kWh Used, and also often 0.7 kWh Used. IOW, the amount of energy from the battery I use to drive the 3.9 miles on this downhill route to the store is about where it has been for many years. This suggests to me that the battery energy used per mile using these slightly heavier version of the OEM tires, once they were "broken in," is about the same as the energy used per mile I was getting using the tires that were on the car when I bought it 9 years ago.
 
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