Subject	There's really two separate things going on here.
Posted by	TheMarlin (MidTN) on October 17, 2012 at 12:43 PM
	This message has been viewed 330 times.
In Reply To	Don't get into it with Antihero, he doesn't understand posted by TriniTT on October 17, 2012 at 10:49 AM
Message	First, you have to consider the rotational inertia of the wheel. This is not directly tied to the weight of the wheel, but rather to the distribution of the mass of the wheel. A wheel with lower rotational inertia will allow you to accelerate and brake faster. Will it cut a second off your 0-60? Probably not, but it does make a difference. I bought some fairly heavy midrange wheels for my Z to replace the stockers. Even though they weigh about the same as the stock wheels, there was a noticeable difference in acceleration because the rotational inertia was lower. Second consideration is unsprung weight. This has to do with the performance of the suspension. Using a simple spring-mass model of the suspension, the response of the system is slower with a heavier wheel. Which translates to reduced grip and stability while cornering, going over rough pavement, etc. This isn't too technical but I hope it helps.
Follow Ups	Unsprung weight - ZiNnYc 08:07:13 10/17/12 also any comments on hybrid weight (n/m) - ZiNnYc 08:33:50 10/17/12 From my experience on bikes, lightweight wheels - michaell32 (FL) 09:12:32 10/17/12 Empirical data > Theory. - Antihero 09:13:45 10/17/12 This test is saying that - ZiNnYc 09:32:27 10/17/12 which is why I didn't claim it was faster. - Antihero 09:35:22 10/17/12 but this isnt too close to call, it did this consistently. - ZiNnYc 09:42:14 10/17/12 lol @ calling 13.6 pounds significant on a 3600+ pound car. - Antihero 10:09:20 10/17/12 ok, so lets extend that theory. - ZiNnYc 10:26:20 10/17/12 Already taken into account. - Antihero 10:37:27 10/17/12 So how about the inertia of the suspension? - ZiNnYc 10:41:49 10/17/12 Yes (n/m) - BigTDogg (MA) 10:51:55 10/17/12 you are still failing to see the big picture. - Antihero 11:01:20 10/17/12 Rotating. Mass. (n/m) - BigTDogg (MA) 11:25:36 10/17/12 and? (n/m) - Antihero 11:27:37 10/17/12 Roll a steel wheel up a hill, then roll a plastic one. (n/m) - BigTDogg (MA) 13:49:50 10/17/12 chaining the wheel to 3500 pounds of steel changes things (n/m) - Antihero 16:31:28 10/17/12 Okey Dokey I guess I'll return my lightweight flywheel, - Zvil 16:51:22 10/17/12 Not really, but I'm not one to yell at a wall (n/m) - BigTDogg (MA) 16:52:52 10/17/12 Point taken. (n/m) - TriniTT 22:05:54 10/17/12 You are failing to understand physics. - TriniTT 12:18:47 10/17/12 accelerating 3600 pounds forward is what your engine's doing - Antihero 13:53:20 10/17/12 Do me a favor and just try it. - TriniTT 22:20:55 10/17/12 2nd. It was a night and day difference between my curb - MixManMash 23:54:47 10/17/12 3rd, 17"Rpf1s w/r888s - TTZEDHEAD 07:07:48 10/18/12 Physics: at 100 mph, the kinetic energy of the wheels - zellamay 15:05:17 10/17/12 Or the other conclusion.. - Antihero 10:13:08 10/17/12 Don't get into it with Antihero, he doesn't understand - TriniTT 10:49:04 10/17/12 Actual heavy wheels like the 21 pound fn01RC's that won? - Antihero 11:06:01 10/17/12 I'm done arguing with you, you're speaking authoritatively - TriniTT 12:10:31 10/17/12 There's really two separate things going on here. - TheMarlin (MidTN) 12:43:22 10/17/12 Absolutely agree, great points there. (n/m) - TriniTT 13:02:03 10/17/12 Well, Rick is a pretty smart guy. - ZiNnYc 18:55:48 10/17/12 you seem to like the maths - BlackholeZ 17:14:53 10/18/12 My NA felt much more peppy when I switched to iForged 18's - KongZTT GT28RS MD 09:40:22 10/17/12 I believe the feel is a separate argument - Antihero 09:44:57 10/17/12 FWIW.. the car felt much quicker to get up from a stop (n/m) - KongZTT GT28RS MD 09:51:49 10/17/12 Grassroots racing mag found not benifit in laptimes... - Hipendicular 13:41:12 10/17/12 I found this on their website.. +1 sizing.. - Hipendicular 14:14:47 10/17/12 Good info. Thanks. (n/m) - Antihero 14:53:29 10/17/12 which issue? - fuzzymonkey 16:12:32 10/17/12 June 2011 is one. I know there was another as well, but - dogpile 16:47:20 10/17/12 Here's one scan from the mag.. - Hipendicular 17:31:46 10/17/12 Not to argue, but .09s in auto-x has been the difference - dogpile 17:44:29 10/17/12 But even GRR mag said it was not conclusive.. (n/m) - Hipendicular 12:40:29 10/18/12 Right, I agree. But saying .09 seconds in a competitive - dogpile 14:18:05 10/18/12 Tire weight made a bigger dif.. - Hipendicular 17:33:29 10/17/12 Wider tire was slower.. - Hipendicular 17:41:20 10/17/12 * tire size, not weight alone - dogpile 17:48:04 10/17/12 Scan part two - Hipendicular 17:35:04 10/17/12 Dyno results - Hipendicular 17:36:41 10/17/12 my neck hurts - fuzzymonkey 17:55:36 10/17/12 June 2011's Project MX5 article. (n/m) - dogpile 17:57:39 10/17/12 its funny how everyone goes on about wheel weight but noone - ztunerz 11:31:45 10/17/12 I was just reading some posts regarding tire weight the othe - Haasz32 11:47:48 10/17/12 I commented on tire weight as well. - TriniTT 12:12:16 10/17/12 yeah me too - toyo t1r were and contis are typically - ztunerz 12:16:50 10/17/12 For those concerned with weight: - Antihero 11:41:00 10/17/12 I agree with you, Rick, the people who actually have the - Jeffblue 12:50:31 10/17/12 Driver skill is a variable that, while important, - ZiNnYc 14:07:07 10/17/12 So basically you are just arguing to argue? - Antihero 14:22:59 10/17/12 Whos arguing? - ZiNnYc 14:30:55 10/17/12 The way I live is... - Antihero 14:51:53 10/17/12 yes, and then he's going to draw some sort of conclusion - Jeffblue 15:29:52 10/17/12 too late (n/m) - Jeffblue 15:30:42 10/17/12 very clever, albeit irrelevant response again. (n/m) - ZiNnYc 19:07:25 10/17/12 Thats reasonable. - ZiNnYc 14:28:27 10/17/12 Mod for a purpose. - Antihero 14:47:03 10/17/12 Agree. - ZiNnYc 15:25:14 10/17/12 When someone claims they bought heavier wheels/brakes/susp - Jeffblue 15:37:49 10/17/12 Jeffrey, this all started with me posing a question - ZiNnYc 19:11:09 10/17/12 Is there tension in NY (n/m) - ali300zx 12:14:51 10/18/12 AMEN! (n/m) - SimaYi 16:03:46 10/17/12 *popcorn* (n/m) - fuzzymonkey 14:45:29 10/17/12 Also would like to add something no one has brought up - TheMarlin (MidTN) 17:16:24 10/17/12 Thank you, ^^^^^this is nice and simple. (n/m) - TTZEDHEAD 19:29:31 10/17/12 so you are saying... - Antihero 20:36:13 10/17/12 Don't know what your problem is - TheMarlin (MidTN) 22:07:41 10/17/12 Face palm (n/m) - TTZEDHEAD 06:07:36 10/18/12 lacks industry backing - Adam (NoVA) 11:59:57 10/18/12 not to nitpick - ZiNnYc 19:45:24 10/17/12 and also this - ZiNnYc 19:51:59 10/17/12 sigh.... - Antihero 20:31:07 10/17/12 Weight isn't directly relevant to this part - TheMarlin (MidTN) 22:18:13 10/17/12 agreed.... but - Antihero 22:34:36 10/17/12 Right. Very rough math: an 18" wheel has to be 75% - zellamay 11:58:29 10/18/12 Can't compare flywheel weight to wheel weight, because - zellamay 11:47:29 10/18/12
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