Steel vs Alloy rims

Sure I thought about it. These rules are often set up to prevent entrants from simply outspending each other for performance benefits. Sometimes they're set up a certain way because the sanctioning bodies are old-fashioned. I brought this up on rec.autos.tech, and some of the racers there said they only used them because the rules forced them to use steel wheels. The sense I got was that they would go with aluminum wheels if the rules allowed them.

They also said that the lighter weight steel racing wheels tend to bend easily and weren't repairable like heavier weight street-legal steel wheels. BTW - Bassett has a street legal 15" wheel that weighs a whopping 24 lbs.

NASCAR requires steel bodies even though fiberglass or carbon fiber would be lighter. They require a cast iron block engine with pushrods and carburetors. They also require steel wheels without wheel covers. You're not going to tell me that these are used because they represent the best performance, are you? They require these things because they're dinosaurs when it comes to technological advances.

Formula 1 is probably the most advanced racing category in the world, and they have been allowed to use light alloy wheels for over 50 years. BBS supplies alloy wheels for several Formula 1 teams:

They simply catched you. This is typical marketing article. They speek about advantages of larger rims a smaller profile tyres as it would be advantages of alloy wheels. They present one example and make conclusion that alloy wheels are "much lighter than steel wheels". This is simply not true.

y_p_w wanted some specefic data fromme, so I provide some:

1) TOYOTA Carina E a) winter wheels: 32 lbs (orig. steel rim 6x14 + Brigestone Blizzak LM 20 185/65 R14 ~70%) b) summer wheels: 36,5 lbs (some Mangels alloy rim 7x15 + Bridgestone Potenza RE 720 195/55 R15 ~70%)

2) SUBARU Impreza WRX a) winter wheels: 36,5 lbs (Impreza steel rim 6,5x16 + Semperit Speed Grip

205/55 R16 almost new ~90%) b) summer wheels: 36,5 lbs (Original gold alloy rim 7x17 + Bridgestone Potenza RE 050A 215/45 R17 ~70%)

Summer and winter wheels have the same overall diameter for every car. (Do the steel weighs more in America? ;-) )

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I think this is also about security. If the steel is good enough for racing, so it should be more than sufficient for normal use.

See my second entry.

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...and restrictor plates, too...so by jiri's=20 logic, we should all restrict our intakes for=20 better performance.

Doesn't Subaru's WRC run on some of those=20 heavier-than-steel BBS alloy rims also?=20

It's a shame they can't afford some decent steel=20 rims, eh?

In article , snipped-for-privacy@volny.cz.nospam says...> y_p_w wanted some specefic data fromme, so I provide some:

You're **including tire weights**, and using

**different diameter & width** wheels (6" vs 7" widths, 14" vs 15").

Same thing again, tho in this case, the wider tire and bigger alloy wheel weigh the same as the narrower steel combo. Ooops...alloy that's bigger AND lighter :-)

Yup.

And what about Formula 1? Did they catch them too? Steel wheels are perfectly legal under Formula 1 regulations, as I understand them.

-- Mark

Of course street-legal steel rims are fine for normal use. That's not what anyone is arguing here. The question is whether or not there are any benefits to aluminum or magnesium alloy wheels. The typical entry-level OEM alloy wheel is lighter/stiffer and transfers heat better than the typical OEM stamped steel wheel. It's very hard to get a street-legal steel wheel that's lighter than what's currently available. However - there are lightweight aluminum and magnesium alloy wheels that are considerably lighter than any equivalent-sized steel wheel, yet street legal.

I think the point to be taken from the weights Jiøí Lejsek provided was that the marketing hype about less unsprung weight was just that. Hype. The buys a car with steel wheels and standard tyres decides that he wants alloys and 'one' of the selling points is this unsprung weight. But then goes for a wider low profile tyre and the only advantage is an extra inch in width, less pounds per sq inch on the road and the ability to produce blue smoke sooner.

(My daughter-n-husband run a wheel/tyre shop and their target market is the boyracer type)

uh, but you're weighing the wheel and tire together.

using your example: (BFG Gforce sport)

205/55 R16 -> 23 pounds for the tire 215/45 R17 -> 21 pounds for the tire.

and so, your steel wheel is 2 pounds heavier if the overall weight is the same.

to compare wheels on a 2002 Subaru Legacy L wagon... (my car) a 15x6 alloy goes as low as 13.5 pounds per wheel

I'm sure a stock steelie is more than 13.5 lbs. maybe someone who's got one can weigh theirs...

Ray

yeah, I guess that's why cars like Vettes and Vipers all come with big fat tires, just for looks. And those silly F1 guys, what do they know?

Again - one person got lots of people to send him weights of several OEM and aftermarket wheel weight. The Legacy (year wasn't mentioned) 15x6 stamped steel wheel was 19.5 lbs. The same-sized Subaru OEM cast aluminum wheels by Enkei and Topy were 16 and 18 lbs respectively. I have no doubt that it's possible to make an extremely heavy aluminum wheel if no care is taken to shave weight. However - the large majority of OEM alloy wheels are lighter than the same sized steel counterparts, in addition to being more rigid.

I don't know what Jiri's problem is. No matter what anyone shows him or is able to demonstrate, he toes the line that steel is better. For any practical consideration, aluminum and magnesium alloy are better, albeit at a greater expense. I can't think of any racing category where steel would be preferred wheel material if aluminum or magnesium were allowed.

Sooner? With WIDER tires? Tell us what you smoke.

Riiiiight. And the option of wider rear wheels/tires on Carrera is tailored for morons in their 40s with over $70k in their pockets also.

I prefer the apples to apples comparison of equivalent size wheels and tires. The original Mazda Miata came with 14" steel or aluminum alloy wheels. The aluminum wheels didn't really have that boy racer look either, but they weighed 12.3 lbs compared to the 18 lbs of the steel version. That's a case (one among many) where a reasonable application of alloy wheels is clearly superior to steel.

Larger rims with lower profile tires can actually weigh less in total thann smaller, narrower steel rim, higher profile tire combinations. You then get the advantage of better dry grip and improved steering response. A bigger contact patch will reduce the chances of that puff of blue smoke.

Are you reading your own data? The summer tire is two pounds lighter, and since the overall weight is the same, that means the alloy wheel is two pounds heavier than the steel wheel, not two pounds lighter.

Again read your own data. In the example above, a 16 inch steel wheel and tire weighs 36.5 pounds. Subtract the weight of your 23 pound example tire, and you're left with 13.5 pounds. So a 16 inch steel wheel is about as light as your 15 inch alloy wheel.

Make no mistake, you can buy extremely light alloy wheels. But you will spend lots of money to do so, and risk destroying a wheel every time you hit a deep pothole. Most people buy much more durable and less expensive alloy wheels. These wheels are usually just as heavy as steel wheels. Their primary advantage is that they look a lot nicer than steel wheels.

I thought it was the other way around.

If you had X amount of weight applied to the ground through a tyre contact area Y then the any turning force applied tothe wheels would propel the vehicle forward. But if the turning force exceeded the friction between the wheel and the road the tyres would break traction and spin. If you then widen the wheel you increase the size of the contact patch that would reduce the pounds per square inch in contact with the road. You apply the same amount of force to the same vehicle weight then with a lesser pounds per square inch the tyres would exceeded the friction between the wheel and the road the tyres would break traction sooner.

Less weight per sq inch to prevent spinning.

Dunno, My maths are a little rusty :>)

Well - I do remember high school physics, where in a perfect friction world, contact area didn't matter as much as the coefficient of friction. However - the real world isn't theoretical physics, and megabuck cars have wide and tall tires that don't easily break away into a cloud of smoking rubber.

I don't see open cockpit cars using narrow tires, or spinning their tires in a cloud of burning rubber. They use really wide tires and seem to know what they're doing.

However - the comparison is between a wider and taller alloy wheel.

I can't imagine a street legal 15x6 steel wheel weighs

13.5 lbs. The lists I saw (where wheels were weight without tires) were between 18-24 lbs.

Again - the stock 16x6.5 WRX wheels weigh 16.5 lbs, which compares favorably with the 19 lbs. I can't figure out what's going on with all those calculations, but here's an actual list of Subaru Impreza wheels:

15x6 Impreza OEM steel: 19.5 lbs 16x6.5 WRX OEM aluminum alloy: 16.5 lbs

The stock 16" WRX wheel is plenty strong. They're not superlight, but they are lighter than the corresponding steel wheel. I know that steel wheels can take more abuse and are easier to repair. However - the fact that steel flexes more isn't an overall performance benefit.

Severe off-road truck racing is still primarily "steel wheel" territory. If you've ever seen a bent rim "fixed" with a 20# sledgehammer, you'd know why. Any alloy would break under boulder slams like these dudes do.

Certainly that makes sense. I guess a heavy steel wheel would be more in the "bend not break" mold. However - that's completely different than the stresses encountered on pavement.

However - I can't imagine any racetrack use where steel would be an advantage. Like I said - NASCAR mandates all sorts of outdated technologies because they're dinosaurs.