Force=mass*acceleration

if there is no acceleration mass will not come into play

 

you are confusing yourself here by throwing inertia into the equation. inertia will never helping a vehicle do anything except cruise farther with foot off the pedal.

also, I would like to know who on this website spends more time going a constant speed than accelerating? Remember that when youre on the freeway, how often are you ACTUALLY staying the same speed? I know I pretty much never do.

http://www.northamericanmotoring.com...s-mileage.html

to be honest, you are arguing against personal experience, so youre obviously not correct. on top of my experience, I have a friend who changed from 50 lb combo to a 35 lb combo, same wheel diameter, same tires, and picked up 4 mpg. Thats an average over his other tanks and he is weird and actually keeps track of each tank. you cant argue with that...

 

So you don't hit the gas peddle while driving?

Sure at idle, mpgs won't change.

But in the real world, where people actually drive it will

 

Btw here is the equation that I used to formulate the differences in dead weight vs sprung weight (again this is related to a bike which in theory/actuality is the same as a vehicle). This is directly quoted from my project

 

the wheel itself doesnt have much friction and the difference between aluminum and steel probably doesnt exist (air hits the wheel and causes friction...negligible). but the wheel is attached to the tire, which you admit encounters rolling resistance. you cant accelerate the tire to overcome this without accelerating the wheel

 

yes, but you hold the gas peddle steady true?

if what you are saying was correct then you would have to gradually apply more and more pressure to the pedal

 

 

Coulomb friction, named after Charles-Augustin de Coulomb, is an approximate model used to calculate the force of dry friction. It is governed by the equation:
where

• is the force exerted by friction by each surface on the other. It is parallel to the surface, in a direction opposite to the net applied force.
• is the coefficient of friction, which is an empirical property of the contacting materials,
• is the normal force exerted by each surface on the other, directed perpendicular (normal) to the surface.

how do you overcome the force of friction to maintain a constant speed without providing force through the wheel

 

Inertia is a VERY important part of the equation tho. it is in every day-to-day driving scenario.

when cruising at speed. (which I make 300+ mile trips often) that rotation mass working for you keep you at speed will help drop the RPM's maybe only 10rpms, but that 10 rpms over 300 miles at a consistent 75 mph which is about 4 hours or 240 minutes is 2400 revolutions your engine does not have to turn.

granted the world is not perfect, but inertia is a VERY important part

 

No, that's not what I'm saying.


Stop and go traffic, getting up to speed, passing, driving up hill all require acceleration. Most driving isn't just sitting at one single speed. It's constantly changing during daily driving.

 

and for ever action there is an equal or opposite reaction.

meaning that for every uphill you have to go down hill, for every acceleration off the green stop light you have to decelerate at every red light.

it comes out NEARLY equal and consistent in the end over a large data sample

 

I dont think you understand angular acceleration. answer these questions

If you let off the gas, does your vehicle continue at a constant speed?

When you apply the gas, does the engine provide power to the wheels?

When your engine applies power to the wheels, is this a force?

Is force = mass * acceleration?

 

It doesn't come out equal. You still have to slow that extra weight down. Which means higher braking force or longer stopping distance.

Getting that weight up to speed and back down Will require extra energy

 

unless youre cruising the freeway with an unlocked tq converter the RPM will be the same no matter what is on the end of the axle, the difference is the amount of power it takes to maintain speed. on the freeway, the difference is not as large as in town, but heavy wheels, once at speed, will continue to suck up power as they are forced to rotate, making them less efficient than lighter wheels. like I said, on the freeway its not as large of a difference but it is definitely still there and if the weight difference on the wheels is enough (10 lbs/wheel is definitely plenty) you will notice it in MPG

 

what are you talking about? the rotational mass would help you if you needed to coast through red lights, not stop. the extra mass rotating doesnt help you use less gas while stopping for a red light...