Ideas on reducing unsprung mass

OMFG don't get me started LOL!!!!!
My Italia is now 124kg (273.5 lbs) lighter than stock, here is mod list

Hmm wonder why she feels faster and more agile
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will a 19" wheel clear the brakes?

 

Very nice list of modifications!

You're tempting me to remove my power seats lol

Ray

 

I know: I couldn't resist posting my .02 when I saw a thread on weight reduction LOL

In the case of unsprung weight, there is however only so much one can reduce;
I do not know how much difference in performance a few pounds less would make.

Btw I am now on a strict post-Italy binge diet to be able to fit in the Sabelts once
I get home

very best

 

Oh boy.. xoxoxo

 

To further chime in:

Wheels: I reckon you can get some pretty ltw wheels out there and save
a bit there, not much though unless you go with a super expensive totally
cf wheel.
You can fit the 19i center locks of the Challenge car but in that case you
will have to change to the Challenge break calipers to have them fit the car
and not even sure that will save a lot, if they can even be fitted to a street car.

Tires: they are pretty much all the same weight.

Brakes: the only calipers available are the oem ones, the Challenge does have
different calipers but i am not sure if they can be fitted to the street car and doubt
they are much lighter.
There are aftermarket rotors out there but they are steel, so no weight savings there.

Suspension/struts: the only suspension available is the oem one, there are
aftermarket springs that are pretty much the same weight as the stock ones,
the Challenge suspension is lighter but cannot be fitted to a street car.

Lugs: yes, titanium lugs and valve stem cover save some weight: look at my
chart in previous post.

Bottom line: do not look at unsprung weight to save some lbs.,
unless manufacture your own parts.

ciao!

 

Do you have a link to the Ford wheels?

One important thing to keep in mind about light weight wheels is that it's not only important how much lighter they are, but where they are lighter.

Saving unsprung weight is fine, but reducing rotational mass is even more important - and reducing rotational mass out the furthers relative to the rotational axis is even more critical.

If you are serious about light weight wheels, it pays to study MOI or moment of inertia and exactly what that means in terms of a rotating wheels, such as for a car or (even more importantly) for a motorcycle.

The main issue is you want a wheel that is not just lighter weight, but one which brings to the table far superior MOI as well as weight savings. You can have to wheels which weigh the exact same, but if one has less weight out at the edge of the rim, it will deliver a far (exponentially better) improvement.

The further the weight is away from the rotational axis, the large impact it has with regard to MOI and saving weight in rotational mass areas. I've seen some carbon fiber wheels which do have carbon fiber spokes, but they are bolted onto an alloy rim. Because the rim is the furthest away from the axis, its weight is most critical to reduce (thus you ideally want a true carbon fiber wheel, like used on the Koenigsegg, for example.

I'll give you a real life example: my street bike. BST makes a carbon fiber wheel for my bike (which I have) and several other companies also make very light weight wheels. In fact, several of the competing wheels are within just ounces of the carbon fiber wheels. So you'd think they are about equal right? Nope. The BST is all carbon fiber, so its outer lip and rim are also carbon fiber, which is significantly lighter than wheels that are similar overall weight, but use alloy out around the edge which results in a less favorable MOI.

Just having carbon fiber spokes is helpful, but it's not going to give you the true performance of a full carbon fiber wheel most likely.

Ray

 

Found this link via Google:

2017 Ford GT Carbon Fiber Wheels Detailed - Motor Trend

They appear to be full carbon fiber.

I'll tell you this.. it would make me a nervous wreck to have someone installing tires those. For my motorcycle (which, as mentioned, has custom BST wheels), I refused to allow anyone near my wheels. I built my own custom jig which holds the wheel and allows me to install the tire myself - without ever making contact with the lip. Even then, I was sweating while installing my Pirelli tires on them!

Ray

 

Cool! Are cf wheels really safe? Meaning is the material strong and rigid enough
to support the car's weight, fast rotation, etc.. esp on a high performance car?

best

 

Whether they are, or are not, that still doesn't change the fact that they're fugly.

 

+1! Not a fan of the look either, and the cost.. xoxo

 

Plus, I'd never trust anything made by Ford. Especially at 200 mph.

 

When Ford designed their first iteration of the GT, they bought a Ferrari and took it completely apart, so they could "learn" (translation: COPY). That's not innovation, it's replication. I have no respect for that.

 

+1.

Not much you can do on a Ferrari with CF brakes. Get HRE wheels. Titanium lug nuts (which we already have). Someone in the Scud section did build titanium rotor hats to save maybe 1lb per corner. Perhaps lighter weight/Carbon Fiber Springs? Our dampers should be fairly light. Brembo calipers aren't usually the lightest on the market, but considering the cost, i doubt it's worth changing out.

 

Not so in case of the 19".

You can easily get 19" wheels on the 458 no problem. Ferrari use 19" on the Cali and Cali T. Same brakes.

OZ makes a very light set of 19" and they are not more expensive than any other well made forged monoblock wheel.
The OZ Forgiatas weigh in at 18.4 lbs for the front and 21 lbs. for the rear. Quite a bit less than any of the forged Ferrari offerings. Add to this less centrifugal force due to a smaller barrel than on 20" wheels. As far as wheel weight savings go, the barrel is where you really want to save it. Of course the spokes matter, but getting that rotational weight in towards the center of the wheel is important. This also means that you should start by looking at he weight of the tyres. The Pirelli PZero is 24 lbs. for the fronts and 31 lbs. on the rears. The Micheling MPSS is 22 lbs, front and 31 lbs. for the rear. This is weight saved at the outer most part of the wheel, so it matters the most. Add a bonus of the MPSS being the better tyre as well in terms of performance. If you want to go even lighter, the Pirelli Trofeo R is 1 lbs. lighter in both the front and rear over the MPSS at 21 and 30 lbs.


If you want to go as light as possible, contact Forgeline and enquire about their GA1R Open lug model. Not only is it among the lightest quality forged alloys on the market. I believe they make them in 18" to fit the 458. Remember that the Brembo disc and caliper on the 458 is exactly the same as on the Corvette ZR1 and many who track those run Forgeline 18" rims. They are about the same price as the OZ wheels i.e about 2k a wheel.

Something I'll like to add to this as far as 21" and 22" wheels go. Now, some manufactures make wheels that are about the same weight as the OE 20" forged wheels. However, both the diameter of the tyre and the barrel of the rim increases. This basically has the effect of adding a heavier wheel. The barrel of a 22" wheel is where there would normally be empty space with no rotating mass in a 20" wheel setup. Some also adds tyre diameter to the setup e.g the common 255/30R21-335/25R22 setup. So let's look at this for a bit. You have a wheel that adds no actual weight, but the weight you have, you move outward hence increasing the centrifugal load. This has a great effect on breaking, acceleration and steering. Add to this the tyres. The PZero fronts now weigh in at 26 lbs. so 4 lbs. more than the OE MPSS and the rears weigh in at a hefty 36 lbs. i.e, 5 lbs. more than the OE MPSS a pop. That's 18 lbs on tyres alone over stock. and since the weight is added to the tyres, it's huge. An acquaintance of mine who used to race and currently work as a test driver, puts it simple. Adding 1 lb. to a tyre is like adding 7 lbs to the chassis between the wheels. If that holds true, it's like adding 126 lbs. and you haven't even added the downside of the bigger outer barrel of the rim!!! Think about that a bit before buying the big aftermarket wheels.

 

a Braille Li battery is a fast easy way to lose 34 pounds (sprung) and get improved battery performance too.

Next the titanium lug nuts save maybe 3 pounds of unsprung weight.

The next big step to take would be a carbon fiber rim.

Are they made by Ford? No!

Are they safe? Yes they are actually stronger than metal. But they have the downside of not bein repairable, so if they get curbed and damaged , they must be replaced.

Are they too ugly to live with? Maybe

Can they handle the heat from the brakes? Appearantly so when the rim has heat protecting material painted on the inside or integrated into the carbon fiber resin.

Are they the future? IMO yes.

 

+1 lol

Here is a very good video, which talks about the durability of CF for wheels:

https://www.youtube.com/watch?v=PGGiuaQwcd8

I have carbon fiber wheels on my motorcycle and they are really nice. Initially, I was concerned about running carbon fiber wheels, but once you see them, hold them and work with them, then you quickly understand that it's a very solid and strong material. And, as the video above touches on, I think the basic deal is that CF can handle an impact which would otherwise dent or deform an aluminum alloy wheel; however, the caveat here is that if you push CF beyond its yield point, then you may end up with a nasty fracture as opposed to just a bad dent.

Like I say, I love them the motorcycle, although the difference isn't as night-and-day as I was expecting. Still, you can notice it over bumps and such. It's kinda like someone put pillows under your tires and softened up everything. Doesn't hurt acceleration or braking either - my bike, between the CF wheels, weight savings and other mods - is scary fast. No way can I hold WOT for much over 1 second or I'm doing 150+ or something crazy.

Ray

 

here's a picture of the BST wheels. I have them done in custom matte finish on the bike

Ray
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