trade in 5.3 for a 6.2?

Crf450r420 · October 14, 2014

I'm no physicist, but I don't think this is accurate. I think it's widely known that lighter wheels are more efficient in every way.

There is a guy on here that just put Wilwood brakes on because his bigger wheels wouldn't stop like it did stock. Why do you think that is? It's because of inertia. Things at rest want to stay are rest and things in motion want to stay in motion. Heavy things are more resistant to change so they need more to do so. That means when they are at rest it takes more torque to start them and more torque to spin them up higher at the same rate as the lighter ones. Then they need more friction to stop them from the same motion. Now if you change only the weight of the wheel and keep all other variables the same you will see heavy wheels will do worse in stop and go and heavy will do better when staying in motion.

Crf450r420 · October 14, 2014

Not sure man. Like to see some data on this. If this was true semis would get better gas mileage than trucks, and trucks would do better than cars. If something is heavier typically it takes more energy to move it and stop it

You are changing from one front section to another front section and the large front section catches more wind, so that would only compare to another equal semi. You can't change more then one thing and compare things in a scientific way. There are many ways to test this, but you have to limit the variables to one and that can be hard to do since wind can change constantly. To help combat that they do runs in both directions within a certain time when doing land speed racing. That way there isn't much time for the conditions to change and then you have to fight the wind one way, but it helps you going back.

Crf450r420 · October 14, 2014

Torque to turn the wheel, and torque to stop the wheel, are insignificant to the torques required to push and stop the truck.

That's right, so if you find you are pushing a dead vehicle and can't get it to move from the bumper. Try pushing it by turning a wheel. If you can get a good enough grip it is much easier. Used that to roll the tractor more than once.

Crf450r420 · October 14, 2014

I can prove the DIC is not correct and I can do it by using it to prove it's own self wrong. I filled up today and cleared trip A right away and took off. When I came to 25 miles on the trip I noticed that my MPG was the same as the 25 mile reading.

Coppertone · October 14, 2014

There is a guy on here that just put Wilwood brakes on because his bigger wheels wouldn't stop like it did stock. Why do you think that is?

Because heavier things are harder to stop, they are also harder to move. Please show one reliable source showing that heavier wheels have produced better gas mileage than lighter wheels, when that's the only isolated variable.

KARNUT · October 14, 2014

I think the name of this topic needs to change

Crf450r420 · October 14, 2014

Because heavier things are harder to stop, they are also harder to move. Please show one reliable source showing that heavier wheels have produced better gas mileage than lighter wheels, when that's the only isolated variable.

Like I have time to test this. We could simply make 1/2" aluminum wheel spacers and run the truck down the highway both says say 30 miles. Resting the trip once it is up to 70 mph. Then swap out to 1/2" steel spacers that extend as far as possible in the wheel and do the same. This way the added wind resistance of the wheels sticking out is added to both sides of the test and we are only changing the weight of the rotating wheel. I will admit it's not going to be a huge change as cruising takes a fraction of the power it doesn't to change speed. Problem is I don't have the time. I have to go finish building and tune a 418 LS3. :-)

I think where you are getting the wrong idea is every time people put on heavier wheels it is usually when the put bigger tires one like 35's and then they drive both city and highway. Problem with that is the wheels are wider and that kill mileage also. A wider tire is more grip as there is more contact patch to create friction for turning or pushing mud. This same added friction adds drag and then so does the added wind resistance. Then there is the larger side walls have more flex and added rolling resistance.

If you can find a test proving heavier wheels on a vehicle sustaining it's speed reduces mileage I'll admit I'm wrong.

Jon A · October 14, 2014

IIRC, you're trying to violate the 2nd law of thermodynamics. You put more energy into spinning up the heavy wheel than you can ever recover from its larger momentum. Your same theory would indicate heavier cars would get better mileage on the highway, all else being equal. We all know this is untrue.

Higgs Boson · October 14, 2014

It is very well documented that heavier wheels and/or tires hurt performance and efficiency.

nards444 · October 14, 2014

Like I have time to test this. We could simply make 1/2" aluminum wheel spacers and run the truck down the highway both says say 30 miles. Resting the trip once it is up to 70 mph. Then swap out to 1/2" steel spacers that extend as far as possible in the wheel and do the same. This way the added wind resistance of the wheels sticking out is added to both sides of the test and we are only changing the weight of the rotating wheel. I will admit it's not going to be a huge change as cruising takes a fraction of the power it doesn't to change speed. Problem is I don't have the time. I have to go finish building and tune a 418 LS3. :-)

I think where you are getting the wrong idea is every time people put on heavier wheels it is usually when the put bigger tires one like 35's and then they drive both city and highway. Problem with that is the wheels are wider and that kill mileage also. A wider tire is more grip as there is more contact patch to create friction for turning or pushing mud. This same added friction adds drag and then so does the added wind resistance. Then there is the larger side walls have more flex and added rolling resistance.

If you can find a test proving heavier wheels on a vehicle sustaining it's speed reduces mileage I'll admit I'm wrong.

This is a friendly conversation so dont take it as anything else. But I dont get the logic. But if I were compelled to believe in your logic I think what might disprove is the logic its self. For one it may be easier to keep a heavier object moving, which I dont think so as we deal with gravity and friction, now if this was space and or friction and gravity wasnt an issue you might be right. I may being to believe this in scenario where you can get up to speed and stay there for hours and hours on end. But real world your constantly increasing and decreasing speed both of which hurt MPG and both of which are harder to do with something that weighs more. So I think anything you may gain at constant speed is lost by having to start and stop a heavier object. I am not professional but I dont think we would find a profesisonal or an engineer that would tell us if your looking to gain MPG to add weight.

Coppertone · October 14, 2014

Friendly conversation here as well. If what you are saying is true, people would be putting weights on their wheels to get better mpg, and aluminum wheels would be unheard of.

Higgs Boson · October 15, 2014

Technically there is no such thing as constant speed. Even on cruise control the speed is constantly and imperceptibly adjusting to maintain an average that is perceivable to a human.....Just like when you are standing still your muscles are in constant action to keep you balanced and upright even though you don't notice.

Crf450r420 · October 15, 2014

This isn't a Ford forum, so expect friendly.LOL

Everyone keeps going to normal driving, but I'm not talking about that.

I'm talking about maintaining one speed. Do any of you own a car with a clutch? Do you know how heavy your flywheel is? Do you know how much it weighs with the clutch also? It's usually pretty heavy. You know what happens when you put a lightweight flywheel on it? It revs up and down faster because 10 pounds off of rotating mass is like 100 pounds off the weight of the car. (rule of thumb). It also makes the car harder to drive, if you could just slip the clutch out before without gas and you take 10 pounds off the flywheel it will stall when you try. If you take enough weight of the motor will stall every time you try to let it idle unless you raise the idle. This is because there isn't enough inertia to get to through the next cycle and maintain the revs. If you put heavy wheels on it it will take longer to get to 70 at any throttle and it will take longer to get to 0 no matter which way you do it. You can brake as hard both ways and it will maintain the speed longer. You can coast as the cruise control does and where just throttling down would work before you might find it down shifting to increase the engine braking. Oh, here is one, I use to have a Honda back in 98 and I took the stock 22 pound flywheel off and put on an 11 pound one with a race clutch for some spray. If I used cruse control on the highway and it was flat everything was fine, but up and down hills (over passes are the only hills here) it would jerk forward and back as the old throttle inputs would sling the car around because the reduced mass doesn't maintain speed the same.

Most people don't do all highway driving, so this will not be useful, but if you have a car that spends 95% of the time on the highway you could gain from it. Keep in mind the higher ratio of sprung weight to unsprung weight equals comfort. As your unsprung weight gets closer to sprung weight you loose that riding on a cloud feeling. However almost no one does this and will benefit from lighter until it's jerky to drive.

Crf450r420 · October 15, 2014

Machining steel and aluminum plates to put behind the wheels for full size testing will be costly. I'll have to think of a way to do with an R.C. car or something. Anybody got a CAD that can run simulations?