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I just swapped out my rims for 18.5lb aftermarket vs stock at 21.5 (so I hear) ... I did keep the stock tires as I only have 13000 miles on them...I have to say I spin the tires at almost every stop light...the damn car has too much torque for the crappy stock tires...I can't say anything about the atx trans but for mtx...I really can tell a bit of differance dumping off the 10-15 lbs of unsprung weight. I figure most folks buy new rims AND new tires...my comparision rules out the tires so I just wanted to make the point. The 6S does have a good amout of torque...
 

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I dont think its quite that simple. There is also a matter of where the weight was saved. For example, a 20LB wheel.. with most of its weight on the outter perimiter will be slower then a 20LB wheel with most of its weight cloaser to the center... Simple torque equation shows this pretty well.

Lighter wheels overall DO spin up faster, and while they do not equal big numbers in torque gain on graphs, they do reduce your overall times for the same reason two equally powered cars, but with difference in weight will have different performance results.

All im saying is, calculating certain performance gains based on torque is not a good way to measure performance. Weight reduction will not yield any gains on a dyno in terms of numbers, but certanly will on the track. Thats just my opinion.
 

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I dont think its quite that simple. There is also a matter of where the weight was saved. For example, a 20LB wheel.. with most of its weight on the outter perimiter will be slower then a 20LB wheel with most of its weight cloaser to the center... Simple torque equation shows this pretty well.

Lighter wheels overall DO spin up faster, and while they do not equal big numbers in torque gain on graphs, they do reduce your overall times for the same reason two equally powered cars, but with difference in weight will have different performance results.

All im saying is, calculating certain performance gains based on torque is not a good way to measure performance. Weight reduction will not yield any gains on a dyno in terms of numbers, but certanly will on the track. Thats just my opinion.
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I'm not an engineer. Nor was I good at physics or math. I'll leave that to the geeks here. But never thought that the weight of the wheel had anything to do with how fast it could spin. I thought only the diameter of the wheel had more to do with that.
 

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Ligher flywheel for MTX also has a similar effect. It spins up easier/faster and it reduces the torque you normally lose due to the extra weight. Ligher flywheel doesnt have less diameter though (at least not that I've seen).

Diameter of the wheel does also affect the spin up/torque loss but so does weight, but it also would depend on how far towards the outside of the wheel the weight is.
 

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3 pounds off of rotational mass is a big deal... if i still had a 6S i would buy 13 lb. rota's for it...
 

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I'm not an engineer. Nor was I good at physics or math. I'll leave that to the geeks here. But never thought that the weight of the wheel had anything to do with how fast it could spin. I thought only the diameter of the wheel had more to do with that.
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Lighter wheels can spin just as fast as heavy ones, it's just a matter of how easy it is to get them going that fast.

Imagine a circular piece of paper 1 foot in diameter. You can grab it and spin it around really easy. Imagine the same 1 foot circle of lead. It'll eventually spin around as easy, and will in fact stay spinning more easily, but it'll be a pain to get moving. You certainly won't be able to just flick it with one finger to get it to spin around.

That's opposite extremes of course.
 

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Lighter wheels can spin just as fast as heavy ones, it's just a matter of how easy it is to get them going that fast.

Imagine a circular piece of paper 1 foot in diameter. You can grab it and spin it around really easy. Imagine the same 1 foot circle of lead. It'll eventually spin around as easy, and will in fact stay spinning more easily, but it'll be a pain to get moving. You certainly won't be able to just flick it with one finger to get it to spin around.

That's opposite extremes of course.
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Oh ok. I guess I was just thinking that the heavier wheel would spin slower because applying equal force (i.e. engine power) to get moving a heavy wheel and a light wheel of equal diameter, the heavier wheel of course would take more effort to move. But that could apply to any object of mass. For example, a heavier rock would be more difficult to move than a lighter rock of the same exact size. However, a heavy wheel is still screwed onto the wheel hub by 6 lugs exactly like the lighter one and they are the same exact diameter, so it wouldn't actually rotate "slower"because of weight, but it would take more engine power to get it to the same speed as the lighter wheel.

However, a wheel that is say 2 inches bigger in diameter but equal in weight to the smaller wheel would take longer to get spinning faster because it simply has a longer way to go to rotate completely.

I have no idea what I just said but I said it. :p
 

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You guys have it all wrong......

The true definition of torque is, when you wake-up with "morning-wood" and try to pull "it" down to take a leak.....and your heals come off the floor......That my friends is TORQUE!!!!

As far as your wheel spinning problem......ease up on the right pedal. j/k :D
 

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I dont think its quite that simple. There is also a matter of where the weight was saved. For example, a 20LB wheel.. with most of its weight on the outter perimiter will be slower then a 20LB wheel with most of its weight cloaser to the center... Simple torque equation shows this pretty well.

Lighter wheels overall DO spin up faster, and while they do not equal big numbers in torque gain on graphs, they do reduce your overall times for the same reason two equally powered cars, but with difference in weight will have different performance results.

All im saying is, calculating certain performance gains based on torque is not a good way to measure performance. Weight reduction will not yield any gains on a dyno in terms of numbers, but certanly will on the track. Thats just my opinion.
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the spreadsheet allows 3 differnet inerial mass distribution assumptions. It shows that strait line acceleration difference is minimal. Choose which one ifts your brain best. But, if you look at just the wheel+tire inertia values, once you start spinning a tire in 1st or 2nd, it will then spin up the tire quicker if it has less inertia. this alone does not make the car quicker.
 
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