香港快意討論區 - Powered by Discuz! Board

標題: High performance wheel [打印本頁]

作者: paul 時間: 2009-7-10 09:52 標題: High performance wheel

Dear all,
Just thinking about new shoes for my horses, it triggered me in thinking about what is the essential parameter of high performance wheels (not tyres). We are always talking and thinking of high performance in car issues, so we should never overlook this topic. I understand you all have much experience in this, it would be fun to have your sharing.

Sincerely

作者: 古惑強 時間: 2009-7-10 10:02

In the order of priority :

1. Weight
2. Weight
3. Weight
4. Weight
5. Weight
6. Weight
7. Weight
8. Weight
9. Weight
10. Weight

作者: Trevor 時間: 2009-7-10 11:01

2# 古惑強

Agree!!

作者: letsrock 時間: 2009-7-10 11:13

In the order of priority :

1. Weight
2. Weight
3. Weight
4. Weight
5. Weight
6. Weight
7. Weight
8. Weight
9. Weight
10. Weight
古惑強發表於 2009-7-10 10:02

precise and direct to the point!

作者: PuntoPatrick 時間: 2009-7-10 12:38

full carbon fiber wheel.

作者: peterkoon 時間: 2009-7-10 12:55

full carbon fiber wheel.
PuntoPatrick 發表於 2009-7-10 12:38

貴過架車wor

作者: PuntoPatrick 時間: 2009-7-10 13:04

OZ Ultraleggera
7x15"
4,99 kg

作者: raypoon 時間: 2009-7-10 13:04

In the order of priority :

1. Weight
2. Weight
3. Weight
4. Weight
5. Weight
6. Weight
7. Weight
8. Weight
9. Weight
10. Weight
古惑強發表於 2009-7-10 10:02

條軨夠唔夠硬淨都應該係一個主要因素wor

作者: 古惑強 時間: 2009-7-10 16:30

條軨夠唔夠硬淨都應該係一個主要因素wor
raypoon 發表於 2009-7-10 13:04

I suppose so, but you won't know until you hit something.
A quality light weight wheel will bend and deform when it hits something hard.
A Taiwan copycat wheel will disintegrate under the same scenario.

作者: paul 時間: 2009-7-10 17:40

So, there are some basic points to think about:
1. Weight
2. Strength ( a good index to measure is Strength-to-weight ratio)
3. Ductility (Ability to flex)
4. Fatigue resistance

In good old days, wheels are made of steel, they are good in strength (but a low ratio in Strength-to-weight ), they have acceptable ductility and good fatugue resistance, but due to their "weight", they are no means "High performance", thus switch to aluminum is a way to go.
Can anyone write something about the aluminum alloy and other options in materials for high performance wheel? Also the manufacture method and their effect on quality?

作者: paul 時間: 2009-7-13 17:33

本帖最後由 paul 於 2009-7-13 17:39 編輯

Alloy/Steel wheels
In general, alloy wheels differ from normal steel wheels because of their lighter weight, which improves the steering (gyro effect) and the speed (acceleration and braking) of the car. Alloy wheels are also better heat conductors than steel wheels, improving heat dissipation from the brakes, which reduces the chance of brake failure in more demanding driving conditions.
Alloy wheels are prone to galvanic corrosion if appropriate preventive measures are not taken, which can in turn cause the tires to leak air. Also, alloy wheels are more difficult to repair than steel wheels when bent,
For passenger vehicles, alloy wheels are not only for improved driving performance, they are also for cosmetic purposes. The alloy wheel itself is shiny and/or has an intricate design, so there is no need for paint or wheel covers. By contrast, steel wheels either have to be painted steel rims with a chromed wheel nut, or be hidden with plastic wheel covers.
Alloy wheels are more expensive to produce than standard steel wheels, and thus are not included as standard equipment on base models of many non-luxury vehicles, instead being marketed as optional add-ons or as part of a more expensive trim. However, alloy wheels have become considerably more common since the 2000s, now being offered on economy and subcompact cars, compared to a decade ago where alloy wheels were often not factory options on inexpensive vehicles. Alloy wheels have long been included as standard equipment on higher-priced luxury or sports cars, with larger-sized or "exclusive" alloy wheels being options.
A big advantage of alloy wheels is that balancing them is easy. The balancing weights are attached in the centre unlike steel wheels where they are attached at the edge of the rim. Thus wheel balance is not disturbed by tyre removal, etc.
There are different types of alloy wheels. Some are cast, which are the most commonly seen on the road, while others are forged. Forged wheels are lighter and stronger, yet much more expensive than cast alloy wheels. Forged wheels are typically purchased by enthusiasts, luxury/sport vehicle owners.
Most aftermarket wheels are cast, while only a few above are forged, such as DONZ forged, Vellano, and Weld. Many companies have been formed over the years (some recently) due to the increasing demand from street racing enthusiasts and the rising demand for larger diameter wheels.
Cast aftermarket wheels have also been oversaturated due to the vast influx of inexpensive chrome wheels from China and India.
Magnesium alloy wheels, or "mag wheels", are sometimes used on racing cars, in place of heavier steel or aluminum wheels, for better performance. The wheels are produced by one-step hot forging from a magnesium alloy known as ZK60, AZ31 or AZ91 (MA14 in Russia).
The mass of a typical magnesium automotive wheel is about 5–9 kg (depending on size), Magnesium wheels are flammable and have been banned in some forms of motorsport in the UK following fires which are very difficult to extinguish. Mag wheels have been known to catch fire in competition use after a punctured tire has allowed prolonged scraping of the wheel on the road surface. Some variants of Magnesium alloy wheels may have low corrosion resistance.
They have the disadvantages of being rather expensive and not practical for most street vehicles. Aluminium wheels are often mistakenly called "mag wheels".

作者: 古惑強 時間: 2009-7-13 17:58

So, there are some basic points to think about:
1. Weight
2. Strength ( a good index to measure is Strength-to-weight ratio)
3. Ductility (Ability to flex)
4. Fatigue resistance

In good old da ...
paul 發表於 2009-7-10 17:40

1. Weight is most important, inertia mass of the wheel has 2x effects as compare to weight put on the chassis of the car during acceleration.
2. Strength, very important factor indeed, but unless you are going for super ultra light weight models, or you are putting low low low profile tyres on, you don't need to worry too much about it.
3. Ductility, it is a safety issue that if a wheel hit a hole or a kerb, a good one in the worst case will deform a bit, while the tyre will stay intact to ensure safety. The not so good one will disintegrated, and the tyre will have a big risk of falling off.
4. Fatigue resistance, don't worry it, most will last longer than the cars.

作者: 古惑強 時間: 2009-7-13 18:00

OZ Ultraleggera
7x15"
4,99 kg
PuntoPatrick 發表於 2009-7-10 13:04

Nice, Taiwan 15" copycat weights around 8kg.

作者: paul 時間: 2009-7-18 11:53

本帖最後由 paul 於 2009-7-18 20:07 編輯

Some knowledge in different kinds of wheels and manufacture methods

All Wheels Are Round. Or Are They?
Though not enforced, there are quality standards to govern the production of wheels. Some countries though, like Germany and Japan, have government regulations requiring aftermarket wheels to meet certain criteria and ensure proper fit. The United States has taken steps to establish guidelines but it will be some time before they can enact regulation of any kind.
Consequently, all wheels are not made the same. The performance of an alloy wheel is a direct result of the manufacturing technique employed.
The Tire Rack offers a wide range of wheel choices from manufacture's that have adopted the manufacturing processes that meet the strict O.E.M. (Original Equipment manufacturers) requirements. Wheel companies that supply to the O.E.M. market must follow certain procedures during the manufacturing process to maintain the quality and integrity of their product.
There are many factors to consider when purchasing an alloy wheel.
What Is a Wheel and What Is a Rim? Are They the Same Thing?
It may seem obvious, but a wheel is comprised of a hub, spokes and rim. Sometimes these components will be one piece, sometimes two or three. The hub is the center portion of the wheel and is what attaches the wheel to the suspension. The spokes radiate out from the hub and attach to the rim. The rim is the outer part of the wheel that holds the tire. While many people refer to wheels as "rims," this is technically incorrect. We'll discuss several ways that wheels are manufactured below.

One-Piece Cast Wheels
This is the most common type of aluminum wheel. The casting of wheels is the process of getting molten aluminum inside a mold to form a wheel. There are different ways this can be accomplished and although it sounds simple, this is truly an art when done properly.

GRAVITY CASTING
Gravity casting is the most basic process of pouring molten aluminum into a mold utilizing the earth's gravity to fill the mold. Gravity casting offers a very reasonable production cost and is a good method for casting designs that are more visually oriented or when reducing weight is not a primary concern. Since the process relies on gravity to fill the mold, the aluminum is not as densely packed in the mold as some other casting processes. Often gravity cast wheels will have a higher weight to achieve the required strength.

LOW PRESSURE CASTING
Low pressure casting uses positive pressure to move the molten aluminum into the mold quicker and achieve a finished product that has improved mechanical properties (more dense) over a gravity cast wheel. Low-pressure casting has a slightly higher production cost over gravity casting. Low pressure is the most common process approved for aluminum wheels sold to the O.E.M. market. Low-pressure cast wheels offer a good value for the aftermarket as well. Some companies offer wheels that are produced under a higher pressure in special casting equipment to create a wheel that is lighter and stronger than a wheel produced in low pressure. Once again in the quest for lighter weight, there is a higher cost associated with the process.

Spun-Rim, Flow-Forming or Rim Rolling Technology
This specialized process begins with a low pressure type of casting and uses a special machine that spins the initial casting, heats the outer portion of the casting and then uses steel rollers pressed against the rim area to pull the rim to its final width and shape. The combination of the heat, pressure and spinning create a rim area with the strength similar to a forged wheel without the high cost of the forging. Some of the special wheels produced for the O.E.M. high performance or limited production vehicles utilize this type of technology resulting in a light and strong wheel at a reasonable cost. BBS has used this technology for several years in their production of racing wheels for Formula One and Indy cars. BBS's RC wheel for the aftermarket is an example of a wheel produced using spun rim technology.

Forged
The ultimate in one-piece wheels. Forging is the process of forcing a solid billet of aluminum between the forging dies under an extreme amount of pressure. This creates a finished product that is very dense, very strong and therefore can be very light. The costs of tooling, development, equipment, etc., make this type of wheel very exclusive and usually demand a high price in the aftermarket

Multi-Piece Wheels
This type of wheel utilizes two or three components assembled together to produce a finished wheel. Multi-piece wheels can use many different methods of manufacturing. Centers can be cast in various methods or forged. The rim sections for 3-piece wheels are normally spun from disks of aluminum. Generally, spun rim sections offer the ability to custom-tailor wheels for special applications that would not be available otherwise. The rim sections are bolted to the center and normally a sealant is applied in or on the assembly area to seal the wheel. This type of 3-piece construction was originally developed for racing in the early 1970s and has been used on cars ever since. The 3-piece wheels are most popular in the 17" and larger diameters.
There are now many options for 2-piece wheels in the market. The 2-piece wheel design does not offer as wide a range of application that a 3-piece wheel allows, however they are more common in the market and the prices start well below the average 3-piece wheel. Some 2-piece wheels have the center bolted into a cast or cast/spun rim section and other manufacturers press centers into spun rim sections and weld the unit together. When BBS developed a new 2-piece wheel to replace the previous 3-piece street wheel, they used the special rim-rolling technology (originally developed for racing wheels) to give the rim section the weight and strength advantages similar to a forged rim. On the high-end of the 2-piece wheel market you can find wheels using forged rims and forged centers. Since these are only sold in small volume and due to the high development and production costs associated with the forging process, they tend to be on the high end of the price scale.

作者: 古惑強 時間: 2009-7-18 12:13

I guess the Taiwanese wheels are basically gravity or low pressure casting ones.

作者: Simon 時間: 2009-7-18 13:13

the making of Ray's wheel
http://www.youtube.com/watch?v=Armx02_R7Y0

作者: paul 時間: 2009-8-14 10:38

本帖最後由 paul 於 2009-8-14 14:11 編輯

Carbon wheels,
There are two main type of carbon wheels in the market,
1. Semi carbon
Full carbon fiber rim barrels to minimize unsprung mass and rotational inertia for the ultimate in handling, acceleration and braking performance. It fitted with a traditional forged alluminium spoke and hub, which the outer carbon fiber rim barrel can be replaced if damaged. Since the use of carbon fiber in wheel construction is relative new in wheel industries, this should ba a safe way to put the materials into application.
[attach]451[/attach]

2. Full carbon wheel
Rim, hub and spoke are carbon fiber, it should be the lightest but risk taking construction, no body know how long can a full fibre wheel be serve in normal road condition, there are many factors which could affect the durability of the structure, composite materials are subjected to degrade in material itself during its service life, and its failure form is horriable, just break up into pieces when it breaks

作者: 古惑強 時間: 2009-8-14 12:13

Emm ....... I trust metal more than composite materials to form my wheels.

作者: paul 時間: 2009-8-14 12:18

Me too

歡迎光臨香港快意討論區 (http://forum.hkfiatclub.com/)