Goodyear Fuel Max and PSI to Max MPG

I'm considering these tires as well, so please keep us updated on first impressions, etc.

What psi are you running your Integrities?

I believe the Fuel Max have a sidewall max of 51 psi. I would start by running them at 51/49. If that is too much of a jump for you, start lower and work your way up. I've been happy running my Integrities at 50/48.

PA P

 

Yikes!

50/48 - does your car still fit in the garage?

I'm running my Goodyear Assurance's at 40/38 and I was worried.

 

My wife did break the antenna off backing out of the garage, but she claims the garage door was not completely up.

Even at that pressure they still wore out on the edges first.

Miyelani, remember that rolling resistance improves 25% through the life of the tire, so your first mileage will likely not match your worn out Integreties.

PA P

 

I'd suggest higher, but if that's what you feel comfortable with, sure. You can always adjust later. I use a bicycle floor pump-- readily available, no electric, and a bit of exercise. Can't beat that!

PA P

 

Did you plus size or kept the same 185/65/15 OEM size?

It depends on the tires. If it is softer, you need more PSI to feel like the Integrity.

 

Many people here run pressures 10-20 psi over the recommended tire pressure. The folks who are truly hypermilers run pressure significantly higher (as far as I can tell). You can get better mileage by running higher pressures. How much? I run 52/50 psi front and rear and probably get 1-2 mpg better. I don't know if that is about average or not. I'm fairly new to the car (November purchase) but am able to get 55-60 mpg highway with no or light wind and temps > 60 F.

As you know tires have a recommended pressure for a couple of reasons. The main reason is handling. The tire performs best at the recommended pressure. The second is that your ride will be harsher with higher pressures. Tires may also wear more unevenly with higher pressure (although I think you really have to put some high pressures for that). The only real upside to higher psi is mpg. That's why I do it.

Personally I think it fun seeing just how much you can get out of this car.

There is plenty of information on this site on what people do to get better gas mileage. Tires are just one part. The oil you use. How you drive. Using a scan-guage. All of these can help you achieve your goal.

 

As you may know, Goodyear reports that the Assurance Fuel Max should get around 4% more mpgs than the regular Assurance on the highway. All other things being equal (psi, degree of treadwear, etc.), in the long run, I wouldn't expect that you would get more than 4% better highway mileage than you did on the Integrities.

If there's a "standard" psi among PriusChatters who inflate their tires more than what's recommended on the door, I think it would be 42 front/40 rear.

 

I wrote to Goodyear's Customer Service this week and got this response--

There currently are no such standards and labels on tires. Legislation is
being considered to create a type of rating system for rolling resistance
or fuel efficiency of tires, with rating results provided at point-of-sale
in retail outlets, but not on the tire itself. The legislation would also
require an element of consumer education on proper tire care. But many
questions remain unanswered. Studies show that many varying conditions – no
matter the tire type – affect fuel efficiency. These include type of
vehicle, road surface, vehicle load, temperatures, tire inflation pressure
and more. Also, legislators are concerned that reductions in tread
thickness, volume and mass are among the means available to reduce rolling
resistance, yet those qualities would likely be undesirable if they lead to
shorter tire lives and increased numbers of scrap tires.

The Integrity tire in your original equipment size is the lowest rolling
resistance tire we make for your vehicle​

.

I wrote back asking if I am understanding this correct that the Integrity has a lower rolling resistance than the Fuel Max. I haven't heard back from them. I wonder at times about the reliability of Customer Service info. Michelin gave me the run around as well as I've recorded in another thread.

The lack of concrete RR info is frustrating, but it would at least be helpful if manufactuers could supply a list of their products in order of RR.

PA P

 

Sorry, main reason isn't handling. It's well known in the racing world (autocross or track events) that you will normally be running 4-6 psi or more above what the recommended pressures are.

Like most things in a mass manufactured automobile, things are built to a compromise to satisfy as many people as possible. This means that recommended tire pressures are chosen the same way - basically the pressure that achieves a good balance of performance, fuel economy and ride quality.

 

I got a response from Goodyear this morning, saying that it is correct that the Integrity has a lower rolling resistance than the Fuel Max. Grrrrrrr! Just when I had thought I had made up my mind. My hope was/is for an Integrity replacement that would improve my mileage without going to the short treadlife of the Bridgestone Ecopia or Michelin EnergySaver.

PA P

 

The tire search drama continues--

I called my local Goodyear dealer and asked what they'd recommend for an Integrity replacement if I don't want to lose any mpg. He said the Integrity is the lowest rolling resistance tire Goodyear makes. I then asked about the Assurance Fuel Max. He came back a minute later and said the Fuel Max would be better....

In spite of this conflicting info from Goodyear customer service and dealer I am again leaning towards the Fuel Max. With the 51 psi sidewall max I'm thinking I can bump my current 50/48 up a few psi which should help a bit. I like the 65,000 mile warranty on the Fuel Max over the Integrity. I like the HydroEdge, but don't want the mpg hit or the road noise. Anything I'm missing?

PA P

 

What do you guys think of filling the tires with Nitrogen instead of standard air? Has anyone had experience with Nitrogen in their tires?

 

Air is 78% nitrogen, 21% oxygen, ~1% argon, and small amounts of CO2 and other trace gases. Oxygen and argon are lighter/smaller than the N3 molecule. If all the non-nitrogen parts leaked out, you'd lose some pressure. However, when you top up, 78% of what you add is also nitrogen, making the new mix 95.16% nitrogen. A second round makes it 98.9% nitrogen. With the tyre acting as a filter, the amount of gases other than nitrogen is ever decreasing. That's if the hypothesis that the structure of the tyre is permeable to oxygen molecules, but not nitrogen molecules, is correct.

Even if the proportion of leakage were not 100/0, you'd still get an increasing amount of nitrogen in total every time you inflated the tyres.

According to this WikiAnswers answer, oxygen molecules are about 3% smaller than nitrogen. Given that tyres are designed to be inflated with air, I would expect that the low-permeability liner is designed to hold back both nitrogen and oxygen.

I can't say that I notice great drops in pressure that could be explained by losing the oxygen and not the nitrogen.