Best Tires for FFE

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jeffand

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What are best replacement tires for the Ford Focus Electric?
There are many things to take into consideration when selecting replacement tires. One is how the vehicle will be used, and the type of driving conditions. If you drive in snowy conditions then all season tires that do well in the snow are a must. Since the electric vehicles are so quite road noise from tires should be taken into consideration. Picking the wrong tire will adversely affect the vehicles driving range. I recently went to Tire Racks web site found that they sold 115 tires that would fit the Ford Focus Electric. Of these 115 tires only 28 were LRR (Low Rolling Resistance). Tire rolling resistance has an impact on vehicle fuel consumption estimated to range from about 4% during urban driving to 7% during highway driving.
Tire Rack did a test on Low Rolling Resistance tires to see just how well they stack up. For the test they used a 2nd generation Toyota Prius. The OEM tires on the Prius are Goodyear Integrity. The test showed that fuel economy could be improved by as much as 2 MPG by simple switching tires. The Goodyear Integrity tires are LRR tires. So selecting a non LRR tire could adversely affect the driving distance of an electric vehicle.

http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=121

The Stock tires on the Focus Electric are Michelin Energy Saver A/S P225/50R17. The Michelin Energy Saver did return the best fuel economy on the Toyota Prius. So it looks like Ford did do their research well when they selected these tires for the FFE. So picking the wrong tire could result in a reduction in driving range of about 4 to 8 miles per charge.

Is there an advantage to filling your tires with nitrogen?
Air is 78 percent nitrogen, just under 21 percent oxygen, and the rest is water vapor, CO2 and small concentrations of noble gases such as neon and argon. We can ignore the other gases.

First is that nitrogen is less likely to migrate through tire rubber than is oxygen, which means that your tire pressures will remain more stable over the long term. Tires filled with nitrogen will see a smaller pressure change with temperature swings. Low tire pressure will increase the energy need to move the vehicle. It also reduces the chance of the pressure climbing to high under hot condtions.

But there's more: Humidity (water) is a Bad Thing to have inside a tire. Water, present as a vapor or even as a liquid in a tire, causes more of a pressure change with temperature swings than dry air does. It also promotes corrosion of the steel or aluminum rim.
 
Has anyone looked into the effects of increased inflation pressure (above the 38 PSI recommended?). The maximum pressure is 51 PSI, so I'm sure there's no danger of "over-inflation".

Some time ago I took my regular car to a track day, and the tech staff recommended increasing the pressure to 44 PSI while on the track. I didn't let them back down afterwards, and I've found not only the handing to be better, but the gas economy to be better compared to the recommended 32 PSI.

So maybe higher could be better? Any thoughts?
 
A couple of the affects of using different tire pressue:
-Braking distance will change. With higher pressure, the tire's footprint decreases and less traction. Your tire may break free of the road. With ABS, you may not lose control, but your stopping distance will increase.
-Tires may wear unevenly. A few PSI will likely not matter, but increase PSI will see more wear in the middle lane of the tire.
-Ride comfort. At higher pressure, the ride is less soft and become a little more jittery.
-Tires will "chirp" more. I was down to 32PSI and upped it back to 38. Noticed a little more screeching than before. I'm sure it will occur more often if you increase the pressure...for the reasons listed in my first bullet.

Also, don't exceed the tire manufacturer maximum pressure. I'm not sure of the exact consequences, but likely not a good idea.
 
If you raise your tire pressure from 38 to 40 PSI this shouldn't be a problem, put pushing it up to 48 could prove to be unsafe.
 
Great discussion Jeffand. I love all things Tire Rack.

So far I'm very happy with the stock FFE tires. I would do a replace with the same thing if it comes to new tires.

Nitrogen - frankly I don't see the logic. I have two cars with nitrogen (bought tires at Costco). They are a pain in the rear. I have to go to Costco to fill the tires when they are low. So that means I will probably drive with the wrong tire pressure if I stick with nitrogen. Oh, and guess what, the guys at Costco don't fill the tires to the exact pressure required. They sort of just do a 35 psi and call it a day. One car requires 28 in front, 34 in the rear. And they fill the tires hot - I have to drive over there to get them filled.

I have a really nice pressure gauge, an air compressor, and can check my tire pressure with cold tires (everything I read everywhere says to check them cold). I can do that way more frequently than on a trip to Costco, or some other place that has nitrogen.

So no, from a practical standpoint, I think nitrogen is a bad idea.

I can't even begin to add up the years I've driven cars with tires filled with air - not one time have I had to replace a wheel because the wheel corroded from the inside, or the bead broke due to internal corrosion. I've never even heard of anybody replacing a wheel corroded from the inside.
 
EVA said:
So no, from a practical standpoint, I think nitrogen is a bad idea.
News flash: Compressed air is already 80% nitrogen (just like the Earth's atmosphere).

http://en.wikipedia.org/wiki/Atmosphere_of_Earth

Those "nitrogen fill" tire services, that one might feel the need to throw their money away on, fill your tires with maybe 95% nitrogen (not 100%). So, whatever you're paying for the service, it's only for like 15% more nitrogen than normal (and probably less).

In short, it's a gimmick. Fill your tires with air.
 
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