Potential Unsprung/Rotational weight reduction

[DivineStrike]

So I've been looking into the mods I hope to do in the future. Most of which reduce unsprung weight. It looks like the reductions will be pretty significant.

CF5 in 18x10 I estimate (by looking at weights of other cf5 sizes and comments on how much cf5's weigh more than other forgestar wheels) to weigh in around 21lbs or so. I've looked everywhere for exact weights but most haven't weighed just the wheels yet. So coming from PP wheels that saves about 46lbs in rotational weight alone. Most tires I've seen that I may get (in the 285/35/18 to 295/30/18 range) are about 28lbs a piece. That saves 4 lbs total over the oem Pirellis. Next up AP Racing rotors saves 10lbs per front corner. Then an aluminum DS will save another 17lbs if you have a manual.


That's a total of 87lbs of unsprung/rotational weight saved :eyebulge: I imagine if done all at once you will feel a significant difference in how the car drives.

So how much difference do you think this amount of weight savings will make?

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[Grimace427]

So how much difference do you think this amount of weight savings will make?

Depends on how hard you drive the car. If you commute in nothing but traffic 24/7 it might not be that noticeable. If you track the car like being chased by a tornado you would probably feel a significant improvement with just the wheels. As a complete upgrade it would probably feel like you removed several hundred pounds of weight from the entire car. Turning the steering wheel would show the biggest gain due to the greatest reduction in centrifugal(centripetal? get them confused all the time) forces acting on steering from the lighter wheels and brake rotors.

 

[Todd15Fastback]

Centripetal....

I agree with what Grimace says above, too.

 

[Chameleon]

It will make a huge difference you will notice immediately.

 

[DruidBlack]

You will probably not feel it with your hands or ass in straight line performance but 1/4 mile times. As already noted where you will really feel it is in turns and handling esp on a track at high speeds.

 

[Herr_Poopschitz]

100 lb 'sprung' is eqv to approx a tenth in the quarter or 10 hp at these hp levels. So figure at least that in a straight line.

There is no good rule of thumb for unsprung weight, unfortunately. Some will say 10 lb =100 lb sprung, but the calculations become more complex since you're not only translating a part, but rotating it...which requires calcs for moment of inertia between the previous and current parts.

Blanket statements of the suspension reacting faster, turning easier, etc will all hold true. You will definitely notice the difference...no matter where you drive.

 

[Carzzi]

This is an independently suspended car. As such, the driveshaft is sprung weight, as opposed to previous Mustangs with live rear axles, where 50% of driveshaft weight (if I'm not mistaken) would be counted as unsprung weight.

 

[bluebeastsrt]

If your a drag racer it'll be worth about 2/10s.

 

[DivineStrike]

This is an independently suspended car. As such, the driveshaft is sprung weight, as opposed to previous Mustangs with live rear axles, where 50% of driveshaft weight (if I'm not mistaken) would be counted as unsprung weight.

/rotational weight

.2 seems pretty significant. I've read a lot about what people think the difference is between rotational/unsprung weight and sprung weight. Seems the general consensus is that it's not as much as most seem to think. Probably closer to a ratio of 1:2 depending on where the weight is. The low conversions are estimates done by people using a bunch of math, physics and stuff lol. Definitely a more accurate approach but those numbers don't always tell the whole story

 

[kn7671]

I installed a set of O.Z. Leggera wheels and Michelin Pilot Super Sports in stock sizes equipped on the GT PP. These wheels are about 11-pounds lighter each compared to the GT PP wheels, and the tires are about 2-pounds lighter than stock each, saving 52 lbs of rotational weight.

Did I notice a difference, yes. Initial acceleration is slightly more snappy, braking is more responsive, and the suspension is a little more reactive but less labored at the same time.

I think it was a good investment and am enjoying the outcome. Next up is probably the driveshaft, thinking a CF version like I installed in my S197, as I hate the pinging noises transmitted through the aluminum ones.

Those looking into bigger tires that the stock sizes, if you install a set of Michelin Pilot Super Sports, you won't need bigger tires, as these tires are the Superman of street tires in my opinion.

 

[Carzzi]

Kn, after you installed the Superleggeras, did you notice any improvement in the pitching/bobbing the PP is notorious for during freeway cruise?

 

[willmkent]

I dropped 15 pounds per wheel on my slow ass is300 when I swapped wheels and tires.....let me tell you, the IS300 is sooooo slowwwww. This made such a difference in a sprint and the way the car handled.... At least to me it felt like that

 

[Wblv17]

I would guess 3 tenths in the 1/4 and also a .4 MPG increase on highway

 

[ForTehNguyen]

lowering wheel weight should result in a smoother ride since bumps wont cause as much inertia

 

[Rogues Gambit]

Definitely would consider it, I loved how my A4 felt when I went from stock 17's (23.1) to my Enkei PF01's (19.2 as well as 18's) shaved roughly around 15lbs, loved the rotational feel

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