rotating weight in relation to front wheels.

December 07, 2018, 11:42 AM

329L

quote:
Originally posted by TOP38:
quote:
Originally posted by wideopen231:
This maybe more of opion thing then fact.

We all know the rule of thumb that 1 lb. rotating weight equals 10 lbs. sprung weight. My question does this apply to front wheel and tire weight also? Yes it is rotating. Is it adding more or less load to engine same as rear wheels or flywheel weight? Engine has to work harder to spin those if weigh more. Can see where rolling easier like with better bearings help reduce power used.Does it also take more power to roll front tier over if it weighs 5 lbs more than another equal power to haul 50 lbs heavier driver down the track?

If so change front wheels on FED from weld aluma star(original) to wire spoke would shave .15 off et 15 lbs less x 10 for rotating. Sorry I find that super hard to believe.

First your rule of thumb is wrong! Where the added rotational weight is place matters!

Second, you are talking about adding or subtracting 5 drops of water in a large lake! It just doesn't matter.

Case I point, 7.3 dragster ran the exact same ET and MPH with bead lock's vs no bead locks, same tires!

Move on to something more important.

Bead locks picked me up at that et range.

December 07, 2018, 11:54 AM

TOP38

quote:
Originally posted by wideopen231:
old rule is 1 lb of rotating equals 9 to 10 lbs depending on who you hear it from. HAve never seen or heard where as part of it, Never said I agree with rule.I do agree with where it is does. 1 lb out of axle is not same as 1 lb off tire weight. Also don't agree that off rear end is near same as off flywheel.

I agree with have seen no difference most of the time as in your example with bead lock's and most of that difference is towards outer part of mass.

Again its mostly a opinion thread and all are good.Some opinions backed by have seen work and good amount of have not seen it work out.

Not sure who you hear stuff from but you may want to listen to others! It certainly matters where you add any kind of weight! For rotational weight, the further you add it away from the center of rotation the more energy needed to accelerate it and to also stop it! That's a fact!

December 07, 2018, 12:00 PM

Curly1

I think a lot of the rotational weight thing is over rated. Lighter rotating assembly that makes 750 horsepower does rev up quicker than a heavier rotating assembly that makes 750 Hp but Et is same or little difference.

Not a bad idea to save weight and rotating weight may be better than non but do not expect huge gains IMHO.

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December 07, 2018, 12:14 PM

bill masiello

One little change may not help but put together 10 little changes will show you something !

December 07, 2018, 01:18 PM

wideopen231

quote:
Originally posted by TOP38:
quote:
Originally posted by wideopen231:
old rule is 1 lb of rotating equals 9 to 10 lbs depending on who you hear it from. HAve never seen or heard where as part of it, Never said I agree with rule.I do agree with where it is does. 1 lb out of axle is not same as 1 lb off tire weight. Also don't agree that off rear end is near same as off flywheel.

I agree with have seen no difference most of the time as in your example with bead lock's and most of that difference is towards outer part of mass.

Again its mostly a opinion thread and all are good.Some opinions backed by have seen work and good amount of have not seen it work out.

Not sure who you hear stuff from but you may want to listen to others! It certainly matters where you add any kind of weight! For rotational weight, the further you add it away from the center of rotation the more energy needed to accelerate it and to also stop it! That's a fact!

Also exactly what I said. As for who I hear from as stated OLD rule as in rule of thumb. Just bunch of those old guys who where racing before most of us where born hence old part.

December 07, 2018, 01:23 PM

wideopen231

quote:
Originally posted by bill masiello:
One little change may not help but put together 10 little changes will show you something !

Agree .Goes back to my working to cut few ounces off. Few ounces nothing.Few once 20 times something.If its just work to machine,drill or what ever cost is zero.PLUS gives me warm fuzzy feeling know I cut weight at no cost. Now if spending money I want to get hot fuzzy feeling knowing it helped even if only .0099,see not greedy that would .01009.

December 07, 2018, 01:49 PM

HS professor

My change was simply rims, not tires. Heavy steel rally wheels with centers and rings to light at the time aluminum Welds. I did weigh it at the time but forget the numbers, It was a decent amount. I had used the same 215/70 radial fronts and Mcreary 275/60's out back. That car ran anywhere from 12 teens to 20's and the rims alone meant nothing in terms of performance. I expected at least a .10 or so.