Interesting observation about MPG with new truck tires

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Feb 15, 2003
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My 2011 F150 Ecoboost has been returning excellent MPG lately, in fact the MPG has been steadily but slowly improving over the last 6 months. I was actually over 21MPG average for the first time ever. I started thinking about how the engine is finally broken in at 140,000 miles, or maybe it's running a bit lean,,, who knows. But I was not complaining.

Well fast forward to this week with a new set of (same as before) Michelin/Costco LT tires. MPG is back down to 16.5-17 and the truck feels like it's being held back a bit. The new tires are great in the rain, and ride really well. But they absolutely have reduced MPG. Yes, the old tires were down to the tread wear indicators.
 
New tires have a higher rolling resistance than worn tires - all other things being equal.

There can also be as much as a 60% difference between make/models of tires in the same size.

OE tires (the ones that came on the vehicle from the assembly plant) are usually the lowest RR tires you can find in the size - meaning that replacing those tires is going to hit the fuel economy pretty hard!
 
New tires have a higher rolling resistance than worn tires - all other things being equal.

There can also be as much as a 60% difference between make/models of tires in the same size.

OE tires (the ones that came on the vehicle from the assembly plant) are usually the lowest RR tires you can find in the size - meaning that replacing those tires is going to hit the fuel economy pretty hard!

I didn't know that, but it makes perfect sense. And I'll bet CAFE is hiding in there somewhere as well.
 
The best mpg I’ve found in a truck tire I like is the yoko G015. 21.1 avg is on my ’18s display right now, f150 2.7.
 
New tires have a higher rolling resistance than worn tires - all other things being equal.

There can also be as much as a 60% difference between make/models of tires in the same size.

OE tires (the ones that came on the vehicle from the assembly plant) are usually the lowest RR tires you can find in the size - meaning that replacing those tires is going to hit the fuel economy pretty hard!
I didn't know that, but it makes perfect sense. And I'll bet CAFE is hiding in there somewhere as well.

Where it is hiding (It really isn't!) is that car manufacturers know that tires contribute negatively to fuel economy, so they specify low RR tires - and to get that the tire manufacturers have to sacrifice treadwear and/or traction, especially wet traction. The OEM's know this, but don't care since they don't have to warrant the tires (with a few exceptions).
 
Where it is hiding (It really isn't!)

Sure it is. Yes, consumers like more MPG. But CAFE makes the manufacturers like it even more. Because it involves large dollar payouts if they make the CAFE standard. And at the same time it costs them dearly if they don't. Money is a tremendous incentive.... Both ways unfortunately.

It's why CAFE exists in the first place. Car manufacturers aren't going to do these things out of the goodness of their heart. So it makes all the more sense they provide tires on their new vehicles that deliver the best fuel economy. Especially when you consider the massive discount car manufacturers get that consumers don't, by purchasing literally millions of them every year. CAFE requires that manufacturers search for mere fractions of a MPG, fractions that consumers wouldn't even notice.

And the Michelin Latitude tires that came on my Jeep Grand Cherokee are nowhere near the cheapest. And they are considered to be one of the longest lasting tires in their class. I'm betting that without CAFE they wouldn't be on it. And don't forget, car manufacturers learned a very expensive lesson some years back, by installing cheap, crappy tires on their SUV's.

Remember the whole Ford / Firestone Wilderness tire fiasco? That whole mess ended up costing Bridgestone / Firestone $1.67 BILLION dollars by the time it was over. Ford lost over $5.5 BILLION. All while trying to save a few bucks per vehicle by putting cheap tires on them.
 
Sure it is. Yes, consumers like more MPG. But CAFE makes the manufacturers like it even more. Because it involves large dollar payouts if they make the CAFE standard. And at the same time it costs them dearly if they don't. Money is a tremendous incentive.... Both ways unfortunately.
[...]
Remember the whole Ford / Firestone Wilderness tire fiasco? That whole mess ended up costing Bridgestone / Firestone $1.67 BILLION dollars by the time it was over. Ford lost over $5.5 BILLION. All while trying to save a few bucks per vehicle by putting cheap tires on them.
I'd be interested in hearing what those large dollar payouts are if a manufacturer makes the CAFE standard.

My recollection of the Firestone issue was that Ford recommended a low tire pressure that contributed to dangerous and sometimes deadly handly characteristics on the Ford Explorer. You're suggesting that there was more to it or that the issue was the quality of the tires. I don't remember that.
 
You're suggesting that there was more to it or that the issue was the quality of the tires. I don't remember that.

I'm saying if they would have put proper tires on the vehicle in the first place, there would have been no need to jack around with tire pressure. But that would have cost Ford more money.
 
I'd be interested in hearing what those large dollar payouts are if a manufacturer makes the CAFE standard.
It's more of how much they're penalized if they don't make them. Writing checks to the government for over half a billion dollars is more than enough to get their attention. They also can trade CAFE credits when they exceed the standard. Those credits are very valuable.

"The current penalty for failing to meet CAFE standards is $5.50 per tenth of a MPG under the target value times the total volume of those vehicles manufactured for a given model year. Since 1983, manufacturers have paid more than $590 million in CAFE civil penalties".

 
My 2007 Ram 1500 had worn Coopers on it when I drove it to Chicago. Was getting just over 23mpg. They had very poor traction since I would slip on wet grass. Got new Falken Wildpeak tires that have great traction and are very quiet but average 19mpg. That is all I changed. Same tire pressure as before. I like the new ones.
 
Ah ......... The Ford/Firestone Situation. It was a Firestone problem: Barry's Tire Tech: The Ford/Firestone Controversy

The short version: The problem was exclusively Firestone's. The root cause was a combination of a tread pattern type (that no one uses anymore) and an unusual rubber processing technique (that was obsolete even when this was happening.) The Decatur plant where they used this processing technique was closed in December 2001.

The low inflation pressure specified by Ford didn't help, but it wasn't a root cause.
 
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