High Ridgity vs. Lightweight (wheels) - The True Test

[blitzkrgCT9A]

Hello. I wanted to share with you an article that AME/Endless USA translated into English

regarding the wheel weight vs. wheel rigidity factor. We found it quite interesting and decided

to share with everyone interested in lightweight, 1 pc. sports wheels.

http://www.speedelement.com/images/hosted/option_test1.jpg

http://www.speedelement.com/images/hosted/option_test2.jpg

http://www.speedelement.com/images/hosted/option_test3.jpg

http://www.speedelement.com/images/hosted/option_test4.jpg

http://www.speedelement.com/images/hosted/option_test5.jpg

Thoughts and comments??

[s13 drifta]

I didnt know light weight wheels would give so many negative effects, everyone is always trying to get the lighter wheel, but it shows that you dont have to be light to perform well. Good info.

[Slidin240Wayz]

OMG, companies actually do research and development?

Who woulda thought?!?!?!

[hustlervibes]

Very interesting info. I didn't think that having a more rigid rim would be as profitable as stated above. But of course this is on hard track conditions where as most of us just drive our cars around on the streets with a cruise through a mountain or occasional track events.

[Kn1ves]

well there goes Rota's last selling point

[bejota180sx]

at last a test that supports what i have been saying all this time to my friends that just think LIGHTER=BETTER... thanks for all the info!!!

[ROUGE180]

Really cool article. I have often wondered about this very issue. Maybe not as in depth as this report but just wondered what were the pros and cons. I myself don't track all the time but I do love to drive. I'm all about weight savings but considering the wheels and tires are basically like your feet, I want something thats going to last and be sturdy. I can save the weight in the car itself.

[hustlervibes]

They should compare the RE30 vs. CE28

[HyperTek]

i wonder if they took into account of track temp etc.. 1 sec isnt much, could have been that they tested the commercial wheel first when teh track was warmer, then later swapped to the lighter wheel and the track cooled off a little bit.. or driver could have just had one hell of a run on that first set. They should post all the lap times. Tire pressure cold and hot.

i dunno.. thanks for sharing the ad.

Id like to see a knock off vs. original article. I doubt it would come from a japanese publication as I dont think they have much knock off over there.

[hitman]

thats crazy how the tire moves on the wheel. i never thought about that.

[95KA-Turbo]

i wonder if they took into account of track temp etc.. 1 sec isnt much, could have been that they tested the commercial wheel first when teh track was warmer, then later swapped to the lighter wheel and the track cooled off a little bit.. or driver could have just had one hell of a run on that first set. They should post all the lap times. Tire pressure cold and hot.

i dunno.. thanks for sharing the ad.

Id like to see a knock off vs. original article. I doubt it would come from a japanese publication as I dont think they have much knock off over there.

It depends on what you consider knock off. There are a bunch of companies that copy each other designs.

Very interesting article though. I'd like to see their wheel compared to a Regamaster...since it is lightweight and rigid.

[kdashy]

I had no idea the tire moved that much.

Amazing.

[Sonic Motor]

i wonder if they took into account of track temp etc.. 1 sec isnt much, could have been that they tested the commercial wheel first when teh track was warmer, then later swapped to the lighter wheel and the track cooled off a little bit.. or driver could have just had one hell of a run on that first set. They should post all the lap times. Tire pressure cold and hot.

i dunno.. thanks for sharing the ad.

Id like to see a knock off vs. original article. I doubt it would come from a japanese publication as I dont think they have much knock off over there.


I think knock offs are just heavy and low in rigidity lol

[Mister.E]

i wonder if they took into account of track temp etc.. 1 sec isnt much, could have been that they tested the commercial wheel first when teh track was warmer, then later swapped to the lighter wheel and the track cooled off a little bit.. or driver could have just had one hell of a run on that first set. They should post all the lap times. Tire pressure cold and hot.

i dunno.. thanks for sharing the ad.

Id like to see a knock off vs. original article. I doubt it would come from a japanese publication as I dont think they have much knock off over there.

dude, there are tons of shitty ass no name brand knock off wheels all over the place here. you tend to see a lot of them at places like UpGarage, selling for really cheap prices.

[HyperTek]

well i didnt mean it in a negative way..
a test like nismo lmgt vs rota knock offs etc... somethin like that
but then again i dont know how comparable those would be. Compare a wheel that was designed/engineered to a wheel taht was just cast molded from from the original.

5ZIGEN FN01 vs Emotion CR .. i always thought those where comparable wheels etc

[S14DB]

Some how I see this thread coming up when so guy tries to say his 50lbs knockoffs are better than a quality lightweight wheel.

[aznpoopy]

lol. i hope nobody gets the wrong idea. naturally a quality wheel could easily be lighter AND more rigid than another wheel. on that note, i wonder how RPF1's would fare against the GTC01.

i doubt such a test would be done. unlike the test done in this article, it wouldn't be smart marketing... XD

[SlideWell]

wow, nice find. it would have been nice if they tested Advan TC-II. anyone who has lifted them/driven with them know how ridiculously light they are.

[snowmansent2hel]

nice find quality info

[hellaflush]

im still not selling my te37s :P

[blitzkrgCT9A]

My apologies if these articles are hard to read because I had convert them into JPEG format in order post here. I do have these articles in PDF format if anyone is interested (PM me your email).

[OptionZero]

The test is a little flawed- they used a specially lightened wheel (shaved 3.9lbs down) versus a standard wheel.

Shaving material from the standard design of a wheel corrupts the data you get from that wheel. The test should have used wheel model *intended* to be that light- presumably whoever's manufacturing and engineering a wheel will redistribute material to provide strength, instead of designing a wheel first then haphazardly shaving it down to meet a target weight.

I have no doubt wheel rigidity matters, but this test does not prove anything.

Re-do it with an unmodified "light" wheel versus an unmodified "rigid" wheel.

[[w]hite[r]abbit[x]]

im still not selling my te37s :P

i'm currently pondering junking my Rota Grids and getting Volk TE-37's. I auto-x often and Rota's aren't just doing it for me.

[drift freaq]

Just proves my 57 MAX's rock :D hehehehehehe I could not resist saying that.



P.S. for those that did not realize the statement above is tongue in cheek.

[A Spec Products]

hite[r]abbit[x];1813305']i'm currently pondering junking my Rota Grids and getting Volk TE-37's. I auto-x often and Rota's aren't just doing it for me.

I don't think you need to make THAT big of a jump

I'd definitely say getting rid of the Grids are going in the right direction

But there are many wheels that are good that aren't exactly as big of a price tag as TE37

For example, RPF1 would be a logical choice for someone into auto-x who wants budget minded good quality wheels

TE37 are great wheels, but are not the end all wheel and won't make you better at driving

But I think at minimum you need to be on some form of quality made wheel

[jackjack]

interesting. nice find.

[Wiisass]

This test sucks for a lot of reasons. It's marketing BS for one. What they're trying to say is that the whatever wheel is heavier than others, but if we weaken the same wheel down to the weight of another totally different designed wheel, the car will be slower. So they're justifying the heavier weight of the wheel that they're selling.

They shaved down the wheel to the minimum safe stiffness according to an FEA model. How was the model validated? Was it validated or verified in any way?

How about about if didn't shave 4 lbs off the wheel and only shaved 2 lbs?

Tire temps look low for what tires they are. I would expect high 100-low 200 deg F, not 140 deg F max.

Those are the big things that stuck out and I didn't read the article yet, so I might change some things, but I will probably be adding more.

Does it say how many laps they ran? And only tires temps for one axle?

I'll read it later in full and have more.

So who else thinks that a number of people on here are going to be against really lightweight wheels now due to misinterpreting the intent of this article?

[blitzkrgCT9A]

I don't think anyone is going to go against lightweight wheels because of this article. The article is to show that sometimes lightweight wheels don't mean anything if its not rigid. Overall balance is the key.

[OptionZero]

Regardless of what your point was, the test is so flawed it cannot be used as substantive evidence of...well..anything.

[Daniel.]

Cal (EDIT: or is this Devin?) I was gonna steal these scans you posted on norcalevo and post them, but i guess you got to it first. hehe

[blitzkrgCT9A]

I don't have a point to prove here. Just thought it might be a useful info to share.

And quite frankly, if you want them (Enkei) to do a test against other brand's wheels, its not likely to happen. Manufacturers will not conduct any tests like this against their competitors. There will be a war if they do that and not very professional. :)

If more tests will make you at ease, you can write a request to Mackin/Rays and see if they are willing to do a similar test on their line of wheels?

I am sure they will be up for it.

[sijia10358]

wow..i didn't even know that tires move on the wheel....i need some of that anti slip paint!

[Matej]

Wow I'm so glad I have curbkilling Sportmax tank wheels haha.

[cdlong]

why, they're probably neither stiff nor light.

the article is just saying that weight is not the only functional factor to consider when choosing wheels.

[Matej]

I was kidding.

[babowc]

very cool article.

never knew tires moved on the wheel that much!

[atom]

The point of the article was that rigidity is something that needs to be looked at as well as weight. That's why they needed to use the same wheel design, to try and show the effects of rigidity and ONLY rigidity.

It's really the title of the article that is flawed. Calling the article "high rigidity vs. Lightweight" implies one or the other, which isn't true. The tire slippage thing was kinda interesting.

[Chernobyl]

I think this article just shows that the Enkei GTC-01 will be the next big bandwagon nutswinger zilvia dreamer kid wheel.

Because it was in some Japanese mag.

[inertiaticism]

wow..i didn't even know that tires move on the wheel....i need some of that anti slip paint!
Another thing that can cause that is using silicone lubricant to mount tires with instead of water or alcohol based lube that will evaporate.
I usually use whatever I can find that's slippery when mounting rear spares myself, but I was told that this is a common problem by the Hunter tech that came by the shop I used to work at to service our tire machine.
Especially on large diameter, low profile tires, he said he's seen a lot of lazy tire techs hose the rim and bead down with PTFE spray lube or something, and then they keep coming back because it will not stay balanced at all.

[sideview_180sx]

CE28 has always been lighter then the te37, te37 is just more rigid. re30 is a similar shape to enkei gtc-01. my friend runs re30s in honda challenge h4. previously he had fn-01r (forged). he said the the re30s were more rigid/lighter. Enkei was smart in using a wheel of same design. mixing te37 with ce28 add-in the variable of wheel weight/shape. BTW anyone ever look and enkei nt-03 that wheel has had that rigidity ring around it for ever.

[veilside180sx]

NT03 is considered by most to be THE strongest cast wheel on the market. Enkei's MAT technology really is very good.

[BBSilvia]

Very cool article, great info!!!!!!!

[jeeper_x]

what about the 3 and 2 pieces wheels?

do they have less rigidity than cast/forged 1 piece wheels?

[azndoc]

Good info to know.

So I'm thinking TE's are good then. Not that much would change my mind anyways about TEs

Awesome.

[kenshinS14sks]

what a great read and find! so how would we exactly be able to figure a wheel is too light, or good balance... rpf-01 for example (one of my top choices) ... too light...good rigidity? are all the rims made by enkei balanced?

[cdlong]

too light is not possible. not rigid enough is.

[veilside180sx]

Good info to know.

So I'm thinking TE's are good then. Not that much would change my mind anyways about TEs

Awesome.

The Volk Racing wheels are very strong/rigid for their weight, so i wouldn't worry a whole lot about that.

[LoanShark]

Enkei was smart in using a wheel of same design. mixing te37 with ce28 add-in the variable of wheel weight/shape.

thank you. took the words right outta my mouth for all the technicality nay-sayers.

Its just good-to-know info. take it as that and nothing more.

OP, thanks for posting.

[Slidin240Wayz]

TE37 are great wheels, but are not the end all wheel and won't make you better at driving



hahaha...so true.

Look cooler..YES!

[HyperTek]

they should do a low offset vs high offset challange, that would be interesting. or a wide rim with a certin width like 235 and then a narrower wheel with teh same sice tire.

[300hp owen]

Id like to see a knock off vs. original article. there is some reference to this idea on the last bit of the article -
"Enkei Speaks: Regardless of whether the wheel is cast or forged, if the same design and raw materials are used, the rigidity factor will be equal.
Furthermore, the weight will not be affected either."

I understand Rotas are heavier than their copied originals from Desmond, Volk, etc., but I think with the same design and at least similar materials, that the Rotas are probably just as rigid as the originals that cost so much more.

I also never knew the tires would shift around the wheel like that, it is amazing and probably ONLY from heavy track use with such extreme temperatures (from braking) and it makes sense that wheels/tires can go out of balance if you dont pay attention to this scenario of movement. No doubt the use of lubes to MOUNT the tire in the first place is the reason for most of the movement, especially for the common user.

cool article, kind of a bogus test in that they shave a wheel for the comparo, like others have said it leads to a less than ideal test, but I understand the ideas they are trying to convey... "buy the newest enkei wheel because its better than last years enkei wheels" lol. just like every company every year has something that is new and 10x better than their product from the year before.

If more tests will make you at ease, you can write a request to Mackin/Rays and see if they are willing to do a similar test on their line of wheels? I am sure they will be up for it.hey I am sure TireRack would be up for it, theyre always happy to bolt on some different wheel/tire setups to their BMWs in the back lot and flog them for some testing to publish!
So I'm thinking TE's are good then. Not that much would change my mind anyways about TEsyeah but CEs are stronger and lighter than TEs!
and then REs are even stronger and lighter than the CEs!
TEs are old news. they are amazing wheels but they have been improved upon many times already, even by Volk themselves, in the CE and then RE models.

[300hp owen]

sry dblpost wtf

[OPP]

Very interesting find, good info.

[tbowzer]

interesting article. Nice find

Tire temps look low for what tires they are. I would expect high 100-low 200 deg F, not 140 deg F max.

the metric system..

[S14DB]

there is some reference to this idea on the last bit of the article -
"Enkei Speaks: Regardless of whether the wheel is cast or forged, if the same design and raw materials are used, the rigidity factor will be equal.
Furthermore, the weight will not be affected either."

I understand Rotas are heavier than their copied originals from Desmond, Volk, etc., but I think with the same design and at least similar materials, that the Rotas are probably just as rigid as the originals that cost so much more.

I doubt the Rota's are the same alloy or the same density. If that was the case then they would be the same weight.

I would also expect the price difference to be only 10-25% if the same materials were uses. Cheaper materials I think is where they save the most money.

[Wiisass]

interesting article. Nice find

the metric system..

Why would I say 140 deg F max when the highest number is 60? Did you realize that 140 deg F equals 60 deg C?

[PoorMans180SX]

I doubt the Rota's are the same alloy or the same density. If that was the case then they would be the same weight.

I would also expect the price difference to be only 10-25% if the same materials were uses. Cheaper materials I think is where they save the most money.

+1 to you. I hope this article doesn't start another "Rota budget vs quality wheel" war with all the internet bullcrap that goes along with it.

Why would I say 140 deg F max when the highest number is 60? Did you realize that 140 deg F equals 60 deg C?

hahahaha, people don't know math Wiisass!

[racer98]

Past experence. any rim below 20lbs is just asking for problems for street or track. Bridgestone RE55"S" = Cup racing tire in japan is a damm good track / street tire.

[Pank]

you better tell every person who drives a stock miata that their wheels are unsafe

[Risu2112]

Yeah, the primary problem with the test is that while they have a hard and fast measurement for wheel weight, they have no such measurement for rigidity, (such a measurement isn't really easy, best you could probably do is a bunch of benchmarks for comparison).

Also it looks like they kept the alignment the same for both sets of wheels, a minor adjustment would probably offset a reasonable amount of the problems found with the lighter wheels.

Still a good read though! More testing to get some more concrete results would be great, just difficult since there's so many heavy variables.

[azndoc]

yeah but CEs are stronger and lighter than TEs!
and then REs are even stronger and lighter than the CEs!
TEs are old news. they are amazing wheels but they have been improved upon many times already, even by Volk themselves, in the CE and then RE models.

That's nice.

But I've always loved the way TEs looked.

Simple.

So yeah.

[kdashy]

Past experence. any rim below 20lbs is just asking for problems for street or track. Bridgestone RE55"S" = Cup racing tire in japan is a damm good track / street tire.

you better tell every person who drives a stock miata that their wheels are unsafe

Hah, or a prius.

[blitzkrgCT9A]

CE28 has always been lighter then the te37, te37 is just more rigid. re30 is a similar shape to enkei gtc-01. my friend runs re30s in honda challenge h4. previously he had fn-01r (forged). he said the the re30s were more rigid/lighter. Enkei was smart in using a wheel of same design. mixing te37 with ce28 add-in the variable of wheel weight/shape. BTW anyone ever look and enkei nt-03 that wheel has had that rigidity ring around it for ever.

NT03 is considered by most to be THE strongest cast wheel on the market. Enkei's MAT technology really is very good.

Thats absolutely correct. And it is why most Grp N race cars in Japan use Enkei wheels because they are strong, rigid and cost less than forged wheels.

I was lucky enough to get a set of these from a friend of mine in Japan...
http://www.evolutionmr.net/img/images/blitzkrg/s14_nt03_6.jpg
http://www.evolutionmr.net/img/images/blitzkrg/s14_nt03_3.jpg

[ripnbst]

OMG, companies actually do research and development?

Who woulda thought?!?!?!

Wait but theres no mention of Sportmax or Rota anywhere in the article?:eek2:

[axiomatik]

really, this comparison is bogus. I think everyone here is smart enough to figure out that a stiff wheel is better than one that deflects a lot. But what this article is trying to suggest, is that light weight == less stiff, which is certainly not the case. You can't just shave material off and and say that the wheel is pretty much comparable. It's not. By shaving off the material, you have removed the grain structure on the surface of the material. Forging and rotational casting (which I believe the MAT process is) results in stronger material becacuse the processes results in the grain structure of the material to be elongated and aligned, especially at the surface. This grain structure is the reason why those processes result in stiffer, stronger parts. When you mill material off the wheel like that, you blow away that grain structure, and the result is that you have made a bigger reduction in strength and stiffness than you have in weight.

I'd be much more interested in a comparison between this wheel and another that was specifically designed for light weight, like the hollow-spoke advans (don't know the model), and if they did some tests to measure the stiffness of the wheels for comparison.

[blitzkrgCT9A]

ADVAN wheels are made by Enkei.

[email protected] mentioned about testing some of the wheels they carry in comparison (in a subaru forum), but nothing is concrete yet. I hope they will tho :)

[cdlong]

really, this comparison is bogus. I think everyone here is smart enough to figure out that a stiff wheel is better than one that deflects a lot. But what this article is trying to suggest, is that light weight == less stiff, which is certainly not the case. You can't just shave material off and and say that the wheel is pretty much comparable. It's not. By shaving off the material, you have removed the grain structure on the surface of the material. Forging and rotational casting (which I believe the MAT process is) results in stronger material becacuse the processes results in the grain structure of the material to be elongated and aligned, especially at the surface. This grain structure is the reason why those processes result in stiffer, stronger parts. When you mill material off the wheel like that, you blow away that grain structure, and the result is that you have made a bigger reduction in strength and stiffness than you have in weight.

I'd be much more interested in a comparison between this wheel and another that was specifically designed for light weight, like the hollow-spoke advans (don't know the model), and if they did some tests to measure the stiffness of the wheels for comparison.

it's supposed to be a direct comparison of stiffness vs. weight. you can't do that with two different wheels. that would introduce so many other factors that it would make the overarching point less clear.

of course a wheel that's stiffer and lighter will be better. as will a wheel that is the same weight but stiffer, and one that's the same stiffness but lighter. balance is the key.

the point of the article wasn't to prove how good enkei wheels are, it was to point out that weight isn't the only factor to consider. something many people (myself included) didn't realize. you could compensate for the differences in less rigid wheels, but that's exactly what you'd be doing, compensating.

[Wiisass]

So I finally read the whole article and it seems like just marketing BS.

All it really tells you is shaving material off of a well designed wheel is a bad idea. I'm sure if Enkei could've made the wheels lighter and retain the specified target stiffness, they would have.

Axiomatik nailed it. And cdlong sounds like he bought into the marketing.

Stiffness is important to consider, but what manufacturer will actually provide this information. Aftermarket wheels need to meet some design standard. These standards probably specify a minumum factor of safety or some other design specs that would need to be met for the wheel to be produced. Now I don't know if the bare minimum stiffness stated in the article is the lowest allowable factor of safety for a wheel that can be sold or if it was based on the actual lowest factor of safety for this situation.

Either way, this test doesn't tell you much.

And the tire temps are surface temps? That won't tell you anything, you need to check core temps to be able to have any data that you can use to compare. With surface temps, if it was a lower or higher ambient temperature they're going to be much easier affected than core temps and even more so if the sun was out or it was cloudy. Surface temps will tell you nothing in this case. They can have a use, but not the way they're trying to use them now.

And a 20 deg C temperature spread is huge. Usually you would shoot for 10 deg F difference from inside to outside with the inner being hotter than the outer. But that's also core temps and like I said before, surface temps are not really useful for this type of comparison.

Everyone needs to remember that light does not equal weak and heavy does not equal stiff, they aren't always directly proportional like that. A lighter wheel can be stiffer than a heavier wheel. It depends on the design and manufacturing process.

As for casting versus forging, it's really hard to say that they will give you to pieces of the same strength when there are so many different actual processes of the two. Different types of casting will give different strengths. Different forgings will give different strengths. Enkei's process seems like it is pretty well thought out and can give higher strengths than other forms of casting.

So please don't take too much from this article. Yes a weaker wheel will be a detriment to performance and safety. A wheel that will flex like that will most likely not last too long. But weight and stiffness are not always proportional.

I would like to see comparisons of wheels from different manufacturers or even just different wheels from the same manufacturer. These would all be wheels that went through the whole design process and are safe for commercial sale. This would give a lot better information than the test the tried to pass off as something valuable in this article.

[cdlong]

you guys are reading too much into this. it's not an engineering analysis of different wheels, just an exercise in weight and stiffness. i'd be interested in comparing different wheels too, but i don't see that happening from a manufacturer. tirerack is the only place i see it coming from.

Stiffness is important to consider, but what manufacturer will actually provide this information.

not many provide weights either. but at least that can be measured by the consumer. i've never seen any aftermarket autopart manufacturer provide any analytical stiffness data on anything.

Aftermarket wheels need to meet some design standard. These standards probably specify a minumum factor of safety or some other design specs that would need to be met for the wheel to be produced. Now I don't know if the bare minimum stiffness stated in the article is the lowest allowable factor of safety for a wheel that can be sold or if it was based on the actual lowest factor of safety for this situation.

that's doubtful, that would require some sort of certification, which i've never seen. designers use the factor of safety to make sure they don't get sued and to keep their reputation out of the toilet. cheap wheels are heavy (generally) because the designers don't put enough time into the expensive part of design, engineering and testing.

[Wiisass]

you guys are reading too much into this. it's not an engineering analysis of different wheels, just an exercise in weight and stiffness. i'd be interested in comparing different wheels too, but i don't see that happening from a manufacturer. tirerack is the only place i see it coming from.

I know it's not an engineering analysis. I said in my last post, in the first paragraph, what it was, Marketing BS. And my post was an engineer's analysis of the BS and why it doesn't really tell you anything.

not many provide weights either. but at least that can be measured by the consumer. i've never seen any aftermarket autopart manufacturer provide any analytical stiffness data on anything.


What about springs?


that's doubtful, that would require some sort of certification, which i've never seen. designers use the factor of safety to make sure they don't get sued and to keep their reputation out of the toilet. cheap wheels are heavy (generally) because the designers don't put enough time into the expensive part of design, engineering and testing.

http://www.enkei.com/FAQS.html
Look at number 4.

http://www.eng-tips.com/viewthread.cfm?qid=205821
Second post is by a Senior Designer at Enkei

There's the Tire and Rim Association in the US, there's SAE Standards which are worldwide, there's the stuff mentioned on Enkei's site, VIA, JWL, which is in Japan. There's the TUV in Germany plus Europe's own Wheel and Tire association. And there's JATMA in Japan. And I'm sure there are others. And then there's also manufacturing standards.

So all those random things cast on to your aftermarket wheels actually mean something.

And to think there's no design standards or basis for design is ridiculous. And are you saying that engineering and testing are the expensive parts of design that are usually ignored by cheap wheel makers? I hope you aren't serious or that I'm reading that wrong.

[cdlong]

you put a lot of work into making me look like an idiot, good job.

i guess i was to simplistic in my comment about design standards. of course the company is going to do analysis and follow manufacturing standards, most of what you mentioned (so they don't get sued, like the enkei designer mentioned). but that and the other standards are for safety, to make sure the wheels aren't going to break. there's no performance oriented stiffness rating that i've heard of. reading again, i think i misinterperted what you said. whatever.

[idriveattz32]

cool article, makes me feel better about my Sparco's which use enkie's MAT technology and actually have more spokes than the gtc01, my bigger rears are also a little lighter surprisingly, but not by much.

[Wiisass]

you put a lot of work into making me look like an idiot, good job.

i guess i was to simplistic in my comment about design standards. of course the company is going to do analysis and follow manufacturing standards, most of what you mentioned (so they don't get sued, like the enkei designer mentioned). but that and the other standards are for safety, to make sure the wheels aren't going to break. there's no performance oriented stiffness rating that i've heard of. reading again, i think i misinterperted what you said. whatever.

It really wasn't that much work. I'm on that Eng-Tips forum regularly and the Enkei link came up with the right search terms in google.

And you may have misinterpreted what I said. There may not be "performance oriented stiffness ratings" that you mentioned, but there are design standards. And the stiffness you'll get from a wheel is based on the load rating of the wheel and the forces it will see. It's all part of the engineering process that you have to go through when designing a wheel.

The thing about this test is that the lightened wheel probably would never meet criteria to be put into production. Having a much weaker stiffness is indicative of a lot of other problems that would arise if it were to be sold to the general public. They said it was strong enough for that test, but the durability and fatigue life of the wheel were greatly shortened due to the modification. And I'm sure the wheel wouldn't last too long on the street.

But I'm not just trying to prove you wrong. I'm just trying to make sure that everyone realizes that this "test" doesn't really have any direct corelation to anything useful. And that as long as a wheel was designed properly and passes whatever inspection it needs to go through, it should be fine for what they're using it for.

Also keep in mind that wheels that we put on 240's are also used on heavier cars. And the wheel manufacturer would need to design these wheels for the heaviest car that will be using them in order to keep them safe. So the same wheel on a 240 will have a higher factor of safety than it would on a heavier car. This does not change the stiffness of the wheel, but the necessary stiffness is going to be relative to the weight of the car.

So less stiff wheels are out there, but I would assume that most wheels from reputable manufacturers will be fine. It's the lighter, cheaper wheels that I would be worried about or wheels designed for a lighter car or different market segment.

[Yuri]

The way the test was done, it was like testing a stock aircraft against one that had a bunch of wing spars removed for lightness.
It's compromised.

[racer98]

Let me get some automotve input from my fellow co-workers at BMW AG about this.


:whip: