CAFE standards are based on “footprint” which is basically the rectangle of the tire contact patches. If you’re a car manufacturer who can’t meet the NHTSA’s MPG requirements for the size of car you produce, you can increase the size of your cars, so they fit in a larger class that requires less of an MPG improvement.
The most effective way to increase the footprint is to widen a narrow car, increasing its footprint toward square.
Am I understanding you correctly? There is a standard somewhere that says you can’t have tires of a certain width on a car unless the car is also broad?
Why is that even a requirement? I thought broad tires were safer, why would the width of the car have anything to do with it?
No, you’re not understanding me correctly. Mostly because I misspoke, so that’s on me, not you.
The contact patches I was talking about are the corners of the rectangle. Everything between the wheels is the footprint.
The area of the footprint basically determines the minimum MPG you can have. (The more complicated point is that it is related to all the vehicles you produce rather than a specific minimum, but that overcomplicates the issue. The point is that CAFE standards provide strong incentives for manufacturers to increase the “footprints” of their vehicles. The larger the footprint they can claim, the less MPG improvement they need to make. So, longer and wider wheelbases.
And this is exactly why we don’t see small trucks like Rangers or Dakotas anymore. I don’t know if it’s because it’s impossible to make an engine that efficient or if manufacturers are just lazy, but the consequence is that they can avoid stricter efficiency requirements by simply making bigger (larger wheelbase) and heavier (body on frame vs. monocoque) vehicles.
I hate this about newer car models. Many are unnecessarily wide. Lanes don’t get wider though.
It is “necessary” for them to be that wide.
CAFE standards are based on “footprint” which is basically the rectangle of the tire contact patches. If you’re a car manufacturer who can’t meet the NHTSA’s MPG requirements for the size of car you produce, you can increase the size of your cars, so they fit in a larger class that requires less of an MPG improvement.
The most effective way to increase the footprint is to widen a narrow car, increasing its footprint toward square.
Am I understanding you correctly? There is a standard somewhere that says you can’t have tires of a certain width on a car unless the car is also broad?
Why is that even a requirement? I thought broad tires were safer, why would the width of the car have anything to do with it?
No, you’re not understanding me correctly. Mostly because I misspoke, so that’s on me, not you.
The contact patches I was talking about are the corners of the rectangle. Everything between the wheels is the footprint.
The area of the footprint basically determines the minimum MPG you can have. (The more complicated point is that it is related to all the vehicles you produce rather than a specific minimum, but that overcomplicates the issue. The point is that CAFE standards provide strong incentives for manufacturers to increase the “footprints” of their vehicles. The larger the footprint they can claim, the less MPG improvement they need to make. So, longer and wider wheelbases.
And this is exactly why we don’t see small trucks like Rangers or Dakotas anymore. I don’t know if it’s because it’s impossible to make an engine that efficient or if manufacturers are just lazy, but the consequence is that they can avoid stricter efficiency requirements by simply making bigger (larger wheelbase) and heavier (body on frame vs. monocoque) vehicles.
Thanks for the explanation. It’s just infuriating
To be brief, some boneheads ages past decided to class vehicles based on footprint rather than simply weight.
They’re wider and longer because the EPA uses the area under the tires to determine fuel economy requirements.
😲😳 That explains so much…
I wonder if dissolving the EPA would lead to smaller cars in a roundabout sort of way.
*NHTSA, but yes.