Foxxtron

iTrader: (1)

I know that some information is sitting somewhere in one of the forums, but I couldn't seem to find any info about the benefits of lightweight wheels.

However, I am somewhat questioning the ad that centerline wheels is claiming that their 21 lb. wheel can yield about 15.1HP more than a 50 lb. aluminum wheel. I probably could see something in relation to HP, since the rim is the very part of the drivetrain that moves the vehicle on the ground other than the tyre, but since there are different power and torque ratings for different engines, you could probably see the part(s) in question.

Does the weight of the wheel yield more horsepower, thus yielding a minutely faster vehicle? I could see grip and cornering possibly being improved, but more horses? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

quickWS6

Where to begin with this one.....

Lets see, it depends on how you define horsepower. If you are talking about power at the wheels, then lighter rear wheels would actually give you more power in that regard. My definition of horsepower is how much power it makes at the crank. There are many things between the flywheel and the tires that can add or take away horsepower.

BTW, the only way that weight will affect horsepower is if it is the weight of the valves, retainers, rods, pistons, crank, etc.

But, removing weight can be as good as adding horsepower. Which is what I think they are talking about here. They are saying that their lightweight wheels (probably skinnies) will take off enough weight that it would be LIKE adding 15 horsepower.

Judd

iTrader: (1)

Rotateing weight makes more of a difference than weight that {for instance}, is removed by takeing out the AC unit or seats. If I remeber right, each 100lbs equals roughly a tenth in the 1/4. 1000lbs would be a second ect. For rotateing weight, it's something like 1.5-2 times the effect. That's why folks like to put on lighter pullies, lighter piston, cracks, fly wheels ect.
In a real sense, it does not add HP. In the real world, it makes the car accelerate faster.

trackbird

iTrader: (4)

I have a chassis book that brakes this down and shows mph as they remove flywheel, tire and chassis weight, but I can't find it right now (I recently moved). But....

Think of it this way. (this is an example...DO NOT TRY THIS!!!!!!!!!). If you had the rear end of the car in the air and put the car in 4th gear, let out the clutch and floored it and used a stopwatch to measure the time to get from 2000 to 6000 rpm, then remove the rear wheels (again....DON"T TRY THIS!!!!!!!) and did the test again, you'd find that it takes much less time to accelerate the motor from 200 to 6000 when it is spinning less weight. Now, if you are not wasting all the power accelerating the weight of the tires in a circle, you could be using it to move the car. Again, DONT" TRY THIS!!!. Now, put the car on the ground, find a flat stretch of road, use 4th gear at 2000 rpm, floor it and see how long it takes to get to 6000 rpm (it will take alot longer than with only the wheels in the air and a whold lot longer than if we had no wheels on it at all). You could also just floor it with the clutch in and see how long it takes to go from 2000 to 6000 rpm, then lighten the flywheel and do it again, etc.

Qucik WS6 is right....as far as flywheel horsepower is concerned. Flywheel horsepower will only be affected by the weight of parts in the motor, crank, rods, pistons, valves, cam, etc. But. The rear wheels move a car and what actually moves a car is the horsepower at the rear wheels. By removing weight from the rotating parts, we use less of that horsepower moving "spinning objetcs" and more of it moving the vehicle. So, lightweight wheels don't make horsepower, they just use less of it and leave more to move the car.

Option 2. Get a bicycle, lift the rear end and spin the pedal by hand as fast as you can. It will take some effort to spin up that rear wheel. Now, find a bike with a smaller, lighter wheel (and the same gear ratio) or take the tire and tube off of the first bike and do it again...it will be easier to spin. Sorry this is so long and I hope it makes sense.

PS, less rotating weight makes it easier to stop a car as well and makes your brakes do less work (grab the brakes on that bike with the wheel spinning, it takes effort to stop a spinning wheel). Hope this helps.....

trackbird

iTrader: (4)

PS

This rotating weight thing can be tested at a drag strip. Have a friend with "skinnies" on the front make a run, then put the 17 inch rims back on and try it again...you will see some et and mph drop with the heavy 17's on the car.

trackbird

iTrader: (4)

If you really want to prove it. Weigh both wheels (the skinnies and the 17's. Run with the skinnies, then the 17's and then put the skinnies on, and add ballast to the car(add the difference between the skinnies and the 17's, that way, the car is at the same weight with the skinnies as the 17's and if the fact that the weight is rotating didn't matter, it should run the same times..but it will actually run somewhere between the two).

I'm done now.....