is there a difference between reducing the weight of your rims and reducing the weight on your car?? would it kinda be like adding a reduced weight flywheel or drive shaft(reducing rotating mass)???

 

yes.

 

No more flywheel HP is gained by lighter wheels, however there should be a decrease in drive train load (so you get some rear wheel HP back).

 

Losing 10lbs in unsprung weight (your wheels, or even if you switched to CF rotors) makes a huge different when compared to 10lbs out of the car.

 

losing unsprung weight drastically changes the handling of the car, but won't improve acceleration much.
There isn't much weight to be lost though, besides changing rims (or buying lighter rotors), and those have a terrible, TERRIBLE acceleration per dollar ratio.
I'd say lose some weight from the car, you can take out the AC and other options, then, if you're really serious, you can remove the sound deadening material and tar.
Personally I'm not much for weight reduction, unless you're building a race car, keep the extra couple hundred (at the most) pounds and just enjoy the car.

 

Yes, it reduces the inertia. Actually, for the wheels, it is two types of inertia, each with its own benefit. Reduced rotational inertia will allow the wheel to accelerate and decelerate faster under throttle or braking. Reduced linear (vertical) inertia allows the wheel to better follow road irregularities and also to return back to its maximum contact position when displaced by larger bumps, making the existing suspension components more effective and reducing shock to the car's balance.

Also, reducing the overall weight of the car will change the car's overall inertia, which is often overlooked by the car magazines which only state the static weight and static weight distribution. For example, which configuration do you think will handle better when inertia is taken into effect given that the front and rear bumpers are each the same distance from their respective wheels?...
a) Car with 1,200 lbs on the front bumper, 1,200 lbs on the rear bumper, and 600 lbs in the center.
b) Car with 50 lbs on the front bumper, 50 lbs on the rear bumper, and 2,900 lbs in the center.
As you can see, both cars weigh the same at 3,000 lbs, and both cars have a 50/50 weight distribution, but car "a" is going to have a severe "dumbell" inertia issue when it tries to maneuver.

 

Unsprung weight plays a *HUGE* role in acceleration. Why do you think a civic (just as an example, because its most common) with huge chrome rims cant get much better than 2.7 60 foot times? Yet an identical civic with stock rims can cut a 2.1?

 

I agree. Any weight removed from rotating mass has a greater effect than removing static weight.

 

Thank you Evil, no one gets that! I can't count the number of times people have failed to understand that all 50/50 cars are not equal.

I have friends who are mechanical engineers who don't get that.

 

most unsprung weight things don't add acceleration... wheels do. there is alot more "unsprung" things besides rims. brakes, shocks, hubs etc.

 

I've read that its a general rule 1 pound of unsprung weight is equal to about 2 pounds sprung weight. If that helps.

 

It doesnt add any acceleration, removing the weight just makes it more efficient. And believe me if I had a spare 800 bucks laying around Id have a CF driveshaft and rear end

 

Pilots get it. Well, some didn't get it, but they are dead now, so they don't count.

I would also like to point out to others that it also makes a difference where the weight is reduced in the wheel. For example, you could have two different wheels of the same static weight, but if one wheel has more mass in the rim it will have more inertia than one that has more mass in the hub. In fact, you could even have a heavier wheel with less inertia than a lighter wheel, depending on where the weight is distributed. This also goes for flywheels, turbochargers or anything else that rotates.

 

im thinking about getting vert rims 11lbs!!! i have the GXL Rims look kinda like a ninja star or somthing but i think they weight 20+Lbs thats almost a 10lb decrease at every wheel