Anijo,

I know we got into a discussion about those 6ULs, but never really finished because we all know when car nuts start B.S.ing about cars it just gets ADD to no end.

I didn't get a chance to explain why I didn't really like them. I like how they look and the fitment it comes in, but I think they are too light. Before anyone starts blasting me for being a complete idiot, you have to remember that the wheel needs to be rigid in order to keep the tire contacting the road where you originally wanted it. What good is 2 degrees of negative camber if the wheels are just going to yield one of those 2 degrees under max cornering?

Anyway, I've long suspected that the ultra-light wheels are too soft and weak for street use. I've seen many 10-ish year old Mugen wheels fatigued to actual cracks at the end of the spokes and that's just 15 inch wheels running 50 aspect tires (on a relatively light car too). I've also talked about this with an engineer from TRD when they were still making engines for Indy cars. Although he was an engine guy, I heard from him that weight wasn't the major driver in wheel design and it was stiffness. They were far more concerned with load vs deflection than the weight. Granted they're going around in a circle almost static condition in a sense.

Last month Modified mag tried to do an actual test for this. I know their test has a million holes in it and the results are probably not that clear. They don't show all their raw data either, so really maybe error alone makes the results inacurate. But if their results are right, even though they won't state the obvious and make their advertisers mad, it's fairly clear that 2 lbs doesn't make a damn bit of difference in their test and also one of the cheaper wheels the 5 zigen FN-01RC is the best wheel of their test bunch. Check out the article, it's interesting even though it's not that complete of a test.

 

The benefits of a light weight wheel are more noticable on the street than on a track, espcially for Indy or NASCAR style racing.

 

This is always been my point towards Nicks wheels. Lower rotational mass helps. Just like changing to a lighter flywheel. With that said. Saving 1-2 lbs going from 18s to 17s makes zero difference in your fully stock car.

You car is not a race car. If you went back to stock at the level everyone here autox/road raced you wouldnt see a difference. Mentally you would. You could put Zumns wheels on and someone told you they were 10lbs a piece you would believe your car was .5 seconds faster.

Losing 50lbs off your gut will do your car more good than trying to shave a pound off your wheels rotational mass. Plus its good for you too. Sorority girls like guys with 6 packs.

I just have to **** block Nick sometimes.

 

Wheel strength is extremely important! There was a really good article posted a few years back discussing this. I will see if I can find it and post it here.

 

Who cares. Everyone knows wheels strength is important. If Nick wants to save 1-2 lbs because it reduces rotational mass and reduces his unsprung weight more power to him. How many things do we do to our cars that only theorectically an improvement. It's not like the RPF1 is a weak wheel.

If there is an argument to be had it's sidewall height but i'm sure his sidewalls on those Dunlops are tough as nails.

 

Hey, I like light wheels too!!! Actually, the lightest most expensive wheel they tested is my favorite. The Volk RE30, too bad I can't afford it.

But anyway, I think the 6ULs are beyond rediculous in terms of them trying to trim them out. And you have to realize for the price they're selling them for, they aren't going to be made with all the fancy forging equipment that Rays or Enkei have access to.

If you guys read into the article more the wheel that is over 2 lbs heavier is faster in both it's min, max and average. I don't think they show that chart on the web article. I wasn't trying to tell Anijo not to do something, but I thought it would be nice to bring it up. It what these forums are for right? Sharing things we come across.

 

Hey, I've started running again but these 12hr days kill me.

The 6UL's I was talking about were on a Miata which is what, 2200lbs? Wheel strength is obviously a consideration/goal but it's a really tough discussion to have. Rally cars for instance run on these incredibly tough (but heinous looking) wheels that are incredibly heavy but they're still much much faster and more manueverable than street cars. I didn't go into my wheels only considering the weight, but trusting in what I was told by other people about the wheel's strength as well but really, short of attaching a camera to the side of our car and hitting a skid pad, I don't know how we can reasonably judge it.

Post mortem? I'm glad my tires are cheap because I'm going to go through a set this summer alone at this rate

 

You guys are taking me the wrong way. I'm not saying anyone here made a bad choice picking a wheel based on weight. It's not like they publish stiffness numbers. Picking a wheel based on weight/cost/style, is really all anyone has to make an educated choice for what wheels they want. That plus I still said there are holes in what they say in the article and I don't really want to try and explain it here. There's a lot of variables they don't control, but if I give them the benefit of the doubt, it really just shows the 5zigen wheel in a good light.

You guys have to agree that 6ULs are a little bit more than extreme. 9 lb 15" wheels for less money than flow formed RPF1s, you guys don't find that questionable at all?

Also, I'm not talking about strength of the wheel alone. I don't think that any of the wheels are weak. I just think they are "soft." To be allowed for street use they have to pass mandatory strength tests. Otherwise they can only be sold as an "offroad use only" product.

When you design car components, you often look at load vs deflection (stiffness) rather than ultimate strength. Compliance is a very bad thing (in most cases), it often defeats the purpose that you intended if something is flexing too much under load.

Rally car wheels are not a very good example. Their primary goal is to keep gravel out of the brakes and take impacts. I doubt rally cars care that much about precise geometry control and compliance. Their ultimate grip levels are probably much lower than their bump loads.

So you guys think I'm full of **** or what? I think the only guy here that hasn't taken this personally is RawRX8...

 

I have the Hot Version of that model of 5zigens (17x9"). I believe the hot versions are lighter weight, but I'm wondering if anyone can comment on the strength of these wheels. I don't have cash for hitting the track now due to unemployment, so I just want to know how they'll hold up for street use.