My experience was replacing some heavy 19 inch wheels a previous owner put on a Carrera, which I replaced with some 18 inch light weight wheels. It made a huge difference in how the car felt. Handling and braking all felt subjectively better. This was especially the case over less than perfect roads. In my case the difference was about 9 to 10 lbs a wheel changing how the car felt overall for the better. Definitely worth the change.

 

It made a huge difference in how the car felt. Handling and braking all felt subjectively better. This was especially the case over less than perfect roads.

Thanks for your feedback!
In terms of handling/feel did you feel the car became more eager to turn (change direction) or just that it felt lighter on its toes?

 

You can find similar discussions on here and rennlist regarding lighter wheels. Apex are popular and can find threads on them with buyers experiencing notable differences even with minor weight decreases on the wheels.

Apex VS-5RS Wheels - Rennlist - Porsche Discussion Forums

991 - Apex VS-5RS Wheels - Am thinking of getting a set of these for my 2018 991.2 Carrera T. Would welcome feedback, opinions, experience and thoughts on these lightweight forged wheels. :thumbup: Thanks!...

rennlist.com

 

Yes, lighter wheels can make a difference in how the car accelerates and feels and maybe even improve acceleration slightly as well as braking feel. I have personally felt it but it also makes a bigger difference on lighter car with smaller motors. A smaller motor with less torque benefits more from the acceleration thing as it helps get it into the power band. The weight savings relative to the overall weight of the car means that and the size and type of engine matters. The 4.0 is a big motor so you might not feel as much impact, but it is also an NA motor so the there would be some benefit at lower RPMs to get it into the power band quicker, but you would probably notice the effects more if you had a 2L motor with lighter wheels than in the bigger motor and you would definitely feel it in a small NA engine even more.

Not that long ago, I replaced the very heavy ZHP wheels on my 330i with same tires and went to BBS CHRs that were about 4 lbs less per wheel. It does feel a little livelier, especially off the line but probably not worth doing just for weight in this case. I also wanted a little change in look too.

Some lighter APEX would've probably made a bigger difference. So if you are doing it for weight and performance alone, it should be a significantly lighter wheel and tire combination. If you do it, let us know what you find out!!

 

An interesting comment from the thread @TooTurbo shared:

"I asked Walter Röhrl if he could detect the difference driving the same 911 with & without PCCB ... shook his head and said no"

While not specifically wheels, the PCCBs do impact unsprung weight ... so that's quite interesting.

Post # 104:

 

Not sure if anyone has weighed the entire PCCB system vs the iron system but mass difference may not that different. The calipers and pads need to be a lot bigger for carbon ceramics so that may offset the lighter composite rotors.

 

I think there is enough tribal chatter on this subjective topic that my gut feeling is to go ahead with this at some point in time.
What I need to decide is whether to get the lighter wheels first or shorter gear-set first.

 

If you want instant “impact to vehicle handling/dynamics and steering feel, [and] steering response,” skip the wheels and get 200 TW tires. The thing is, they raise the limits on the car so high that you can’t explore them on public roads.

 

I have very recently switched to Goodyear Eagle F1 Supersport tires from Michelin PS4S and have definitely felt a sharper steering response.
In fact that has been a bit of a trigger to explore the light weight wheels ... meaning if the steering feels this good now I wonder how good it might be with lighter wheels ... kind of thing

 

My take is that while the differences are appreciable, they are less consequential when you don’t track the car and you end up getting used to whichever side of the weight line you choose, up to a certain point of cos ie let’s not talk about extremely heavy and extremely light wheels. So you can def feel a 7lb per wheel difference, but after some time it won’t be as obvious, and it won’t matter that much for your use case, imo.

I’m likely to optimize for looks, strength and cost rather than light weight in a set of aftermarket wheels for my 718. At least that’s my perspective for now.

 

7 lb. per wheel sounds like a lot. I'm not doubting it, just observing that the heavier wheels must be quite heavy and the lighter wheels quite light.

FWIW, don't be mislead by people claiming a preposterous effect on acceleration. The total inertial difference per wheel would be somewhat higher than 7 lbs per wheel because of the rotational inertia. Exactly how much depends on how far away from the axle center that extra or lost weight is distributed. So it is, say, 10 lbs, then the effect on acceleration is like putting a 40 bag of potatoes in your frunk. It has been claimed on some car fora that the total is ten times that 7 lb difference, or 70 lbs per wheel! The math says that's ridiculous.

OTOH, the effect on unsprung weight could be significant.

 

The total inertial difference per wheel would be somewhat higher than 7 lbs per wheel because of the rotational inertia....

I expect you will notice the difference in suspension frequency response... the car will feel much "livelier", like music with added treble... brightens it up! This effect will last exactly 2.3 canyon runs, after which your brain will have normalized it out. In the subsequent 6 months ego will keep telling you "how much better" the car feels after spending all that $$$, even though you will feel no subjective difference. Then you will forget about the expensive wheels (assuming you have not bent any rims) and concentrate on $$$ suspension upgrades. (I expect by then you will have put me on the ignore list

(Ok, I am teasing you a bit... but only because I was young once and pondered the same things.)

 

I would say, in general, yes, reducing unsprung weight is a good thing. Tires play a significant role (I believe you are aware of that), probably more so than wheels. It's getting the right wheel and tire combination and it might take some experimentation before you get what you're looking for. It also depends what you do dimensionally; are you going to stay with 20s or go smaller or wider? Ultra light wheels are often soft in that they bend easily. You want wheels that are strong as well as light, so you will need to check all of the wheel specifications. On a past M3, I was after the same thing you are now and I went with smaller 18" BBSs that, while staggered, were all under 20 lbs. ( The rears might have right at 20, not sure) However, I also decided to go wider, so, the combination of wider wheels and wider / heavier tires gained back much of the unsprung weight I sought to lose. The car still handled well though... more to do with the tires and the car than the wheels. I also have to say that I really like the look of my stock satin platinum wheels and I don't know that I would actually enjoy a canyon run more if I had aftermarket wheels. Tracking is another matter. My 2 cents

 

@jimmuller your point about weight loss in relation to axle center is really an important one, which gets lost when people are fixated on sheer number of pounds. Tire weight is the most significant, as @Shifter said. Then wheel rim, then spokes an so on. Well designed wheels not only reduce lbs but move mass toward the center. This is not obvious and not evident by just looking at a wheel.

 

Weight is one aspect of wheel design but having high stiffness and damage tolerance is another. Otherwise the rim will be overly compliant which negatively affects handling or crack over sharp bumps

 

@Shifter i totally agree with you about tires. My recent choice of Goodyear Eagle F1 Supersport was driven by their lower weights, according to Discount Tire, compared to Michelin PS4S.

When looking at wheel weights usually it is tempting to go with smaller diameter e.g. 14 lbs for an 18 inch wheel vs 16 lbs for a 20 inch wheel. But then the 18 inch tire might be heavier than the 20 inch version of the same tire, making the math a net negative. Or as you said and observed, going for a wider wheel or tire can eat into any potential weight saving.

if I do this, I will stick to the stock wheel sizes and offsets and stock tire sizes. In other words the wheel+tire combination that has the lowest weight.

I found that for stock 235/35R20 front and 265/35R20 rear, Goodyear Eagle F1 Supersport were the lightest tires.

 

Good to see you’re thinking about this holistically. Tire weight makes a bigger difference than wheel weight because it’s further from the center of the wheel.

Like a couple others mentioned, I noticed a difference switching from stock Carrera sport wheels to 19 inch Apex VS-10RS wheels. That change totaled 30lb reduction and for me it was on bumpy back roads where it was most noticeable : the car responded more quickly and feels less thrown around by the bumps- sort of like the damping has been increased without affecting ride quality. Also switched from PS4 to Conti Extreme Contact Sport 02 tires.

Didn’t notice any difference to acceleration or braking but am rarely at the limit and thus don’t have a big enough dataset.

 

yes, it does. I've tested the following sequence:

1. stock suspension, stock alignment, 20s with OE tires
2. stock suspension, new pads + new slot rotors, front & rear 2.5 negative camber 20s with OE tires
3. stock suspension, new pads + new slot rotors, front & rear 2.5 negative camber 18 X 9 + 18 X 10 custom forged wheels

My feedback is drastically measurable, with a lap time improvement of over 6 track days. Hoping to get more data soon. I think it is the best measurement when changing any components on the car. Verbally, I think it would be hard for me to provide any feedback for a lighter wheel change. because I also changed the width for the front, 8.5 to 9 to fit a bigger tire.

I do feel the speed does pick up a bit, it was quick to get to my brake zone, that's about it.

 

Don't bring 2 wheel vehicles here, they are much much more sensitive to weight difference as they rely on gyroscope effect coming from the wheel and their agility if affected by the wheels.
Different animals.

 

Well, not to be pedantical or pedagogical or anything similar, nor even repetitive and redundant, but it's a common misconception that the gyroscopic effect of the wheels keeps a bicycle upright. Were it true then a modern racing bike with ultralight wheels would be much harder to keep upright than an older 26"-wheel or fat-tire bike. Balance on a bike is maintained by steering the bike back underneath you. There is gyroscopic effect of course but it is small, and bike wheels don't spin nearly as fast as a car's.

Bicycles have much more complex suspensions than cars, BTW, a combination of fork stiffness, wheel, spoke, and tire deformation, some frame deformation, and the rider him/herself. Compared to a car bicycle wheels are much heavier w.r.t. the entire vehicle+rider weight. FWIW, I've built up over a dozen vintage road bikes of varying quality, given away some, still have 8 or 9. I've done some bicycle dynamic measurements comparing fork and over-the-road resonance, for instance. When I was bike-commuting to Rhode Island one of my routes had a steep downhill to the Blackstone River. The higher-end frames handled the bumps with much more control than others. I can tell by feel the difference between clincher tires and sew-ups, and the difference between heavier and lighter gauge spokes. I always thought (but could never test!) that if I rode them blindfolded I could identify each one by feel.

A car is indeed a much different animal, especially w.r.t. handling. But the physics of inertial loading is the same. Move weight out toward the edge and it becomes a greater inertial load, which of course applies only to acceleration and braking, and has a lesser effect on the transients when changing direction.

I'll get off the soapbox now.
Cheers!

 

No insights into handling dynamics but generally lighter is better. It’s not “free” though, as ids a trade off of strength/stiffness for lightness.

Watch out for Litespeeds (magnesium) on poorly maintained roads though, they don’t take impact as well so the HREs (aluminum) would be more durable for daily and canyon runs.

 

I found this to be quite helpful .. a back to back test with matching set of tires on OE wheels and lighter wheels:

 

I fou this to be quite helpful .. a back to back test with matching set of tires on OE wheels and lighter wheels:

Interesting video. Fun to watch the Ring go by at speed, something most of us will never get to do personally.

The conclusions are pretty much what one would expect. When he picked up the wheels back to back it certainly appeared that one was easier to lift. So 27% (I think he said) is a significant reduction in total wheel weight.

There are a few things to consider when applying that lesson to those of us in the "real world". First, the light Cup 2 tires mean that weight saved in the wheel itself is a bigger fraction of the total than with a typical UHP street tire such as the PS4S or P-Zeros or whatever. I don't have tire or wheel weights to look at, never bothered anyway, but a comparison would be instructive. Second, a change in wheel weight is more significant when the car itself is lighter. And that GT3 RS had been further lightened, though not by much, with the lighter exhaust. Make that change in a more "normal" 911 and the effect wouldn't be so dramatic. The driver did say the improvement was subtle, noticeable because he was so familiar with the car anyway. All minor details admittedly but it does say that all those "Crikey"'s might not be so forthcoming in a more mundane application.

Ragardless of those caveats, the big win was over the bumpy sections, exactly where lower unsprung weight is most important. Could he feel the difference in braking and acceleration as much as he said he could? That's a question. An even better test would be for him to do those same runs but without knowing which wheels were mounted, and then make pronouncement about them before he hit that really bumpy section which would certainly give away the wheels' secret identity.

I don't think I'll rush and buy magnesium wheels and Cup 2's. I'd never notice the difference in our runs out to the wildlife sanctuary.

 

As an olive branch to @PeC and @jimmuller, I offer this. I went to Kop Hill Climb this weekend and encountered some amazing cars and motorbikes. This Brough really highlights how bicycle technology morphed into the motorcycles we’re familiar with today.

Many complain about the gearing in a manual 718 - this must have the most extreme gearing ever! I imagine the engine must have revved to 20,000 to make it go over 30mph!

Who needs Carbon Ceramic mega discs?

Chain drive? Shaft drive? Belt drive? What about Leather ‘chain’ V belt drive?

It’s definitely a Bike!

This also caught my eye……😍

 

As an olive branch to @PeC and @jimmuller,

Nice. Speaking only for myself, I see no reason to need an olive branch. It's been an interesting discussion!

Nice pics of the developing technology.

My sweetie and I spent this morning on a 30 mile on our 1982 tandem "bike".

 

Lighter wheels = entering the rabbit hole ?

With 7Lbs weight shaving at each corner, of course there would be some changes in the feeling. In theory you get easier acceleration of the rotational mass, less gyrocospic effect, and less unsprung mass, making the dampening work differently.
On the other hand, maybe the rotational inertia changes are not that significant because it's the peripheral mass (the tyre and wheel rim) that counts more than the hub and spokes.
Also maybe the factory dampers are set for a given unsprung weight and lightening wheels may affect the wanted behaviour, the factory set dampening becoming too stiff.
I have personally no data to tell if the improvement is worth the investment, but yes in theory it should change something.

Coming back to the goals : improving the car "handling" for road use comes down to improved steering feel and braking feel more than effective cornering speed or lateral Gs it can handle.
Changing wheels may improve the feeling but sure a set of good tires (compound and tire pressure can change everything) and a more agressive alignment (0 toe or toe out at the front + increased negative camber) may have a more significant impact on the steering feel. The same for brake feel : more agressive pad compound and a fresh brake fluid would also make a significant difference without having to change costly components.

As said by others here, a car set up is a delicate equilibrium of many compromises and is never ideal except when you have to deal with only one specific situation - a dry track setup is awful on a wet bumpy road or any other "every day use" condition. The ideal setup for Mr X would not mandatory suit the use case of Mr Y.

It's usually recommended to change one thing at a time, small changes being able to lead to great improvements just because it puts you right into the sweet spot of your use case. And it's always a good starting point to try to solve one goal or specific behaviour at a time.
For example :

• turn-in sensitivity / center point numbness
• loading behaviour while turning in
• sensitivity to load transfer / mobility of the rear, do you want it progressive or snappy
• which compliance level for unperfect road surface (not only comfort, also reaction to inputs)

All this can already be fine tuned to some extent playing only with tires, tire pressure and alignment without changing any other part.

Usually lighter smaller wheels/ semi slicks/ camber plates/ coil overs/ ride height - all this kind of upgrades are driving you into the rabbit hole because it implies making changes on many components to keep the setup consistent. Honestly it's only deemed necessary when you need to extract the most of lateral Gs on a track. For canyon roads, you are on a totally different compromise which doesn't really require all the hassle.

But I can understand that having invested in beautiful forged alloys of your choice makes you happy and genuinely feel an improvement - after all we all value things differently and if its worth to you go for it : you don't have to care whether it's worth for others or not

 

@EdAlps thanks for your helpful message. You are indeed correct. It does feel like a rabbit hole

Actually I have been genuinely curious if lighter wheels make a profound difference. My thought process was to become more informed and ask those who have first hand experience. And this has been a very informative/helpful thread. And so far I have learned that tire weight makes a much bigger difference than wheel weight and the differences lighter wheels make are subtle and nuanced and difficult to quantify. It might still be worthwhile, but it is a matter of diminishing returns.

I was debating whether to get (A) shorter gear ratios or (B) lighter wheels and at this point I am quite certain I'll get shorter gears first.

Your suggestion about tire pressure and alignment without changing any other part is something I am definitely going to follow very soon. I think I'll get an alignment with OE camber plates and ask for 0 toe or toe out at the front + increased negative camber. Aftermarket camber plates or control arms, as you said, can become a rabbit hole - so I'll try to avoid that (for now).

 

Addressing a couple points above - one person's "profound difference" is another person's "feels the same." Wine and sound reproduction are prime examples as well.

Tire weight makes a bigger difference than wheel weight, but choosing tires based solely on weight is not advisable. Many other tire aspects will have a bigger impact on car balance and feel.

 

Recently installed Manthey lightweight wheels and brand new Cup2s on my PCCB equipped street driven GT4. The car has 17k kms all put on by me so I am very aware of the driving characteristics before the change. Overall, it feels mostly the same, however I find the mid range punch from 4K rpm up in gears 3,4,5 to be noticeably more spritely. Almost feels like I’ve got a lightweight flywheel.

The car has a sharper look to it that I am enjoying. I still have my OE wheels with PS4S for shoulder season driving too. Pics or it didn‘t happen:

 

Recently installed Manthey lightweight wheels and brand new Cup2s on my PCCB equipped street driven GT4. The car has 17k kms all put on by me so I am very aware of the driving characteristics before the change. Overall, it feels mostly the same, however I find the mid range punch from 4K rpm up in gears 3,4,5 to be noticeably more spritely. Almost feels like I’ve got a lightweight flywheel.

The car has a sharper look to it that I am enjoying. I still have my OE wheels with PS4S for shoulder season driving too. Pics or it didn‘t happen

What color is that? I like it. Fun colors are the best.

 

Lots happening in this thread…

On the topic of tire compounds affecting “feel”, I can +1 this as my first year of ownership was going through various high performance summer and 200tw tires using 18 inch Apex wheels.

Generally, 200tw with stiffer sidewalls (AD09, A052, V730) will change handling dynamics enough to give you some interesting signals from seat of pants feel.

Depending on 18s vs 20s, sidewall deflection by having just more sidewall can be offset by stiffer sidewall on 200tw tires. There are many that can work as daily drivers (read: won’t kill you in the rain).

Going from V730s on 18s after a track day to my street setup 20s on PS4S’s, I don’t lose much feel.

However you want a little bit of deflection for street driving since potholes…elevation changes between roads… etc.

 

Yep, the feel and breakaway characteristics are one reason people choose a specific tire.

My first time running Hoosier A7s was the SCCA runoffs at Laguna Seca and they dramatically changed the car balance toward more understeer. But the transition from grip to slip was more progressive than the Hankook 40tw race tires I had been running and thus staying close to the limit consistently was easier.