Lighter wheels = much faster?

[1_2Many]

According to Centerline's website removing 1 lb of rotating mass is equivelent to removing 8 lbs of vehicle mass. The 20" wheels on the SS model Camaro look like no light weights and I could see them weighing 30 lbs or more each. I know there are large racing wheels out there that weigh around 15 lbs.

So theoretically you could reduce your rotating mass 60 lbs which multiplied 8X equals 480 lbs.

If that is really true then I will definitely be swapping out my big heavy rims for some racing style (i.e. Z06, BBS) wheels.

Oh and for reference:
http://centerlinewheels.com/faq.php#benefits

"Q: What are the benefits of Center Line's rotary forged wheel vs. a cast wheel?
A: 1. WEIGHT: The most significant benefit is weight. For your front-wheel drive car, we manufacture 15" wheels weighing approximately 13 lbs. For your truck or SUV, we manufacture 20" wheels weighing approximately 23 lbs (the same weight as a 17" cast aluminum factory wheel!). See the next question for info on the benefits of a lightweight wheel.
2. POLISH: Due to the density of the grain structure, the polished forged wheel will maintain its luster for much longer than a polished cast wheel which is very porous.
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Q: Why is the weight of wheels important?
A: Wheels are rotating mass/unsprung weight. Every 1 lb reduction in rotating mass is equivalent to an approximately 8 lb reduction in static weight. With lighter weight wheels, you will benefit from increased fuel savings, quicker braking, improved tire wear and better acceleration. Always ask about the weight of wheels. Your vehicle is not engineered for heavy wheels. Therefore, it will not perform well if you effectively put four anchors on it! "

[zebra]

they say every 100lbs shaves .1sec on the quarter-mile

[dieseldave24v]

Sounds logical. This is why they make light weight flywheels, aluminum drive shafts. Weight issues with rims were a huge deal in drag racing. This is when we cam about the magnesium rim. It was great....unitl it caught fire that is. As far as I know you still cant have magnisum rims on a track.

[The_Blur]

Can we get some comparative track times or scientific proof. I want to quantify the truth of these arguments. I agree that you can get a substantial difference based on the wheels. I just wonder if these estimates are accurate.

On a side note, this is a great resource for people to choose lightweight wheels.

[1_2Many]

My father designed a magnesium racing wheel back in the 70's called a Kimtab wheel. They used them on motorcycles and even BMX for a while. I've been trying to convince him to modify the design for automobiles. Our company specializes in magnesium. I'm not sure why they wouldn't be allowed at the strip...most cars today have magnesium bulkheads behind the dashboard and hell VW Beetle engine's have mag blocks. The old Haliburton wheels that are still popular on Gassers and rods are magnesium.

[dieseldave24v]

Originally Posted by 1_2Many

My father designed a magnesium racing wheel back in the 70's called a Kimtab wheel. They used them on motorcycles and even BMX for a while. I've been trying to convince him to modify the design for automobiles. Our company specializes in magnesium. I'm not sure why they wouldn't be allowed at the strip...most cars today have magnesium bulkheads behind the dashboard and hell VW Beetle engine's have mag blocks. The old Haliburton wheels that are still popular on Gassers and rods are magnesium.

I think it has somthing to do with them not bieng able to put them out when they catch fire. Let me do some homework on this

[headpunter]

Originally Posted by dieseldave24v

I think it has somthing to do with them not bieng able to put them out when they catch fire. Let me do some homework on this

blocks of magnesium dont catch fire

[dieseldave24v]

Actually........

Magnesium is a highly flammable metal, but while it is easy to ignite when powdered or shaved into thin strips, it is difficult to ignite in mass or bulk. Once ignited, it is difficult to extinguish, being able to burn in both nitrogen (forming magnesium nitride), and carbon dioxide (forming magnesium oxide and carbon). On burning in air, magnesium produces a brilliant white light. Thus magnesium powder (flash powder) was used as a source of illumination in the early days of photography. Later, magnesium ribbon was used in electrically ignited flash bulbs. Magnesium powder is used in the manufacture of fireworks and marine flares where a brilliant white light is required.

[1_2Many]

Nice Wikipedia copy/paste there, but seriously people. Magnesium is what I do. I have been around it my whole life, it's part of the family business.

headpunter: true, blocks of magnesium don't spontaneously catch fire, BUT that doesn't mean you can't light one. Try telling that to the people at competition hill (Glamis) who light a VW block on fire for night illumination every year. I've seen it with my own eyes.

And the rumor that Magnesium is difficult to extinguish? Well yes if you try and use water, but no if you use a chemical extinguisher or better yet....sand, concrete mix, dirt or anything else that can smother the fire.

We have small Magnesium fires at my work often and we simply either push the part outside and let it burn or pour concrete dust on it. We also have giant chemical extinguishers, but after 20 years at this facility we've never had to use them.

On the other hand my father lost a friend in a horrible magnesium fire back in the day...it was the metal mill that had not been cleaning the walls so over the years magnesium dust had covered all the walls and ceilings....one day an electrical short caused a spark that lit the whole place up like one giant flash bulb. It was so quick that many didn't have a chance to escape. The fire burned so hot that the giant 10 X 20" wooden beams across roof charred a solid carbon shield around themselves and the firemen claimed this saved the structure from collapsing.

[LSxJunkie]

Originally Posted by The_Blur

Can we get some comparative track times or scientific proof. I want to quantify the truth of these arguments. I agree that you can get a substantial difference based on the wheels. I just wonder if these estimates are accurate.

On a side note, this is a great resource for people to choose lightweight wheels.

Lightweight wheels. For me, it's all about the handling. Unspring mass, rotating mass, it all comes into play.

Originally Posted by headpunter

blocks of magnesium dont catch fire

o rly?

[headpunter]

Originally Posted by LSxJunkie

Lightweight wheels. For me, it's all about the handling. Unspring mass, rotating mass, it all comes into play.



o rly?

looks like shavings to me.

[dieseldave24v]

Originally Posted by 1_2Many

Nice Wikipedia copy/paste there, but seriously people. Magnesium is what I do. I have been around it my whole life, it's part of the family business.

headpunter: true, blocks of magnesium don't spontaneously catch fire, BUT that doesn't mean you can't light one. Try telling that to the people at competition hill (Glamis) who light a VW block on fire for night illumination every year. I've seen it with my own eyes.

And the rumor that Magnesium is difficult to extinguish? Well yes if you try and use water, but no if you use a chemical extinguisher or better yet....sand, concrete mix, dirt or anything else that can smother the fire.

We have small Magnesium fires at my work often and we simply either push the part outside and let it burn or pour concrete dust on it. We also have giant chemical extinguishers, but after 20 years at this facility we've never had to use them.

On the other hand my father lost a friend in a horrible magnesium fire back in the day...it was the metal mill that had not been cleaning the walls so over the years magnesium dust had covered all the walls and ceilings....one day an electrical short caused a spark that lit the whole place up like one giant flash bulb. It was so quick that many didn't have a chance to escape. The fire burned so hot that the giant 10 X 20" wooden beams across roof charred a solid carbon shield around themselves and the firemen claimed this saved the structure from collapsing.

So in your expertice.....Is it safe to assume that maybe an issue could be created with a high speed tire blow out. What I am getting at is a car going down a track...or the street and for whatever reason they have a blow out. The rim scraping on the street would create sparks right? Then you would have powdered magnezium flying through sparks. Could this be a problem????

[1_2Many]

No this would not be a problem because in order for the entire rim to catch fire it would have to have concentrated heat on one section. The sparks flying off would instantly burn themselves out.

The way sparks start fires in my business is only if the machinist does not clean his area and sparks land in a pile of light chips which causes a chain reaction. The thick mass of a magnesium wheel cannot be lit with anything except the long exposure from the flame of other magnesium.

As an example you can look up lowriders that throw sparks out...they most often use magnesium blocks mounted under the car to get such large sparks, but the spark is too brief to ignite anything on the car.

[dieseldave24v]

intresting...I guess you really do learn somthing everyday.

[rolnslo]

Interesting...

[Dan]

The rule I had always heard was 1 lb of rotating mass = 6, not 8, lbs.

[Chewy]

depending what the bolt pattern is (5x120), might be able to use BBS which are very popular on BMWs, 22-23lbs

the only downside i find with lightweights, such as magnesium, is that its a soft metal and you can dent your rims very easily.


my input into the off topic section - magnesium blocks disperse heat too quickly to ignite very easily, blow torch a corner for 10minutes it won't work, but u set the entire block in a small (and lower temp) fire place and i guarantee it'll ignite, i've done it twice. So i really wouldn't worry about your wheels igniting unless your brakes, tires, and car are all also on fire. we have magnesium braking components on the aircraft i fly on - brakes and calipers get a LOT hotter than your wheel ever should

[Mr Twisty]

Fires are thermite reaction maybe?

[andyrew]

Why do you think the Camaro race car concept has such tiny wheels and tires?

Coming from a racer, It makes a BIG difference. I have 3 sets of wheels on my Audi, a set of 18's weighing 55lbs ea, a set of 16's with REo1-R's for racing weighing 51lbs, and a set of 15's with snow tires weighing 43lbs. I can tell a huge difference between the 3. In fact I pick up about 1- 2mpg going from the 18's to the 15's as well.

[dieseldave24v]

I was thinking that racers maight use differnt size wheels for a fast gear ration change. If the rim and the tire combo is smaller in diameter you would have a lower final drive ratio "to the pavment" By lower I mean numericaly higher.

[Mr Twisty]

Is magnesium too brittle for wheel torque loads?

[GTAHVIT]

Magnesium is really strong. They use it for aircraft wheels and brakes. Good stuff.

[1_2Many]

Originally Posted by MisterCamaro69

Is magnesium too brittle for wheel torque loads?

Some C5 Vette's have magnesium wheels and I know last gen Z06 did too. Not sure about current Vette's.

[andyrew]

Originally Posted by dieseldave24v

I was thinking that racers maight use differnt size wheels for a fast gear ration change. If the rim and the tire combo is smaller in diameter you would have a lower final drive ratio "to the pavment" By lower I mean numericaly higher.

Its a side effect.

The real reason is because the closer the rotating mass is towards the center, the less work the drivetrain has to do to move it. You find this practiced a lot in low HP lightweight cars, such as the Miata.

For example, if you take a weight and attach it to a rope, then swing it while rotating 3 ft from your body. Then swing it 10 feet from your body. How fast are you able to move? How much work is it? Its the same weight right?

Thats the theory behind a smaller wheel/ or even a smaller tire diameter.

[Chewy]

Originally Posted by MisterCamaro69

Is magnesium too brittle for wheel torque loads?

Magnesium far from brittle, it's much more likely it'll bend/dent

Originally Posted by gtahvit

Magnesium is really strong. They use it for aircraft wheels and brakes. Good stuff.

aircrafts such as the big ones flying over jax all the time