Article: Aftermarket Wheels
04-08-2005 | 02:35 PM
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Article: Aftermarket Wheels
One of the first changes many owners make to their S2000 is selecting an aftermarket wheel. There are many reasons for changing your wheels but it's important to pay attention to certain details.
To make a proper wheel selection it's important to first understand some of the terminology surrounding wheel design and fitment. We'll cover some of the basics here but you are encouraged to seek other independent sources of information. As time passes some of the information will become dated but the basic concepts remain valid.
Construction
The quality of a wheel is a direct result of how it is manufactured. Consequently there is a direct relationship between price and quality. There are two principle methods employed to manufacture wheels: casting and forging. Virtually all wheel options for the S2000 are of alloy construction, usually of aluminium. The OE (original equipment) wheels on the S2000 are a clear coated cast aluminium wheel 16 inches in diameter. Aftermarket wheels include both cast and forged construction in sizes ranging from 16 to 19 inches in diameter. Some are anodized aluminium while others are painted and/or clear coated and even chrome plated.
One-Piece Cast Wheels: This is the most common type of aftermarket wheel. Casting is the process of pouring molten aluminium alloy into a mold where it cools and takes its shape.
Gravity Casting: Gravity casting is the most basic process of pouring molten aluminum into a mold utilizing the earths 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.
Rim Rolling or Spun-Rim: 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.
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 inch and larger diameters.
There are now also many options for 2-piece wheels in the market. The 2-piece wheel design does not offer as wide a range of applications 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.
Fitment
Replacement wheels come in 16, 17, 18 and 19 inch diameters with widths ranging from 6.5 inches to 10 inches or more. Remember that the front wheels of the S2000 are narrower than the rear wheels and you should always size your wheels proportionately. Changing the front to rear width ratio will also dramatically change the handling of your car. Stick to the stock ratio unless you really know what you are doing. The diameter of all four wheels should always be the same.
The ouside circumference of the wheel and tire combination should always remain the same as stock otherwise your speedometer and odometer will become inaccurate. It will also change the gearing ratio causing you to either accelerate at a different rate or change your top speeds in each gear. Take this into account when choosing a tire for your new wheel.
As a general rule, the larger the wheel diameter, the shorter the tire sidewall. The tires on a 19 inch wheel will be little more than rubber bands. The less sidewall your tires have the less forgiving the handling and the more prone the wheel becomes to damage (it's a lot closer to the street).
The offset measurement of a wheel determines how far it sticks out from the hub. The more offset, the farther the wheel will extend from the hub. It you select a wheel with too much offset the wheel will protrude too far from the wheel well and your tires will rub on the fenders. To little and you'll have clearance issues with the brake calipers. Finding a set of wheels with the right offset is critical in selecting a wheel that looks right and functions correctly.
Offset is the measurement from the centerline of the wheel width to the hub mounting surface. For example, an offset of +59mm means that the distance from the centerline of the wheel to the hub mounting position is 59mm and that 1/2 of the width + 59mm protrudes beyond the hub. An offset of -59mm indicates that 1/2 of the width + 59mm protrudes. "Deep dish" wheels generally have a negative offset. All of the proper offsets for S2000 wheels are positive so for all offset measurements quoted in this article you should assume them to be positive (+).
To make a proper wheel selection it's important to first understand some of the terminology surrounding wheel design and fitment. We'll cover some of the basics here but you are encouraged to seek other independent sources of information. As time passes some of the information will become dated but the basic concepts remain valid.
Construction
The quality of a wheel is a direct result of how it is manufactured. Consequently there is a direct relationship between price and quality. There are two principle methods employed to manufacture wheels: casting and forging. Virtually all wheel options for the S2000 are of alloy construction, usually of aluminium. The OE (original equipment) wheels on the S2000 are a clear coated cast aluminium wheel 16 inches in diameter. Aftermarket wheels include both cast and forged construction in sizes ranging from 16 to 19 inches in diameter. Some are anodized aluminium while others are painted and/or clear coated and even chrome plated.
One-Piece Cast Wheels: This is the most common type of aftermarket wheel. Casting is the process of pouring molten aluminium alloy into a mold where it cools and takes its shape.
Gravity Casting: Gravity casting is the most basic process of pouring molten aluminum into a mold utilizing the earths 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.
Rim Rolling or Spun-Rim: 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.
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 inch and larger diameters.
There are now also many options for 2-piece wheels in the market. The 2-piece wheel design does not offer as wide a range of applications 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.
Fitment
Replacement wheels come in 16, 17, 18 and 19 inch diameters with widths ranging from 6.5 inches to 10 inches or more. Remember that the front wheels of the S2000 are narrower than the rear wheels and you should always size your wheels proportionately. Changing the front to rear width ratio will also dramatically change the handling of your car. Stick to the stock ratio unless you really know what you are doing. The diameter of all four wheels should always be the same.
The ouside circumference of the wheel and tire combination should always remain the same as stock otherwise your speedometer and odometer will become inaccurate. It will also change the gearing ratio causing you to either accelerate at a different rate or change your top speeds in each gear. Take this into account when choosing a tire for your new wheel.
As a general rule, the larger the wheel diameter, the shorter the tire sidewall. The tires on a 19 inch wheel will be little more than rubber bands. The less sidewall your tires have the less forgiving the handling and the more prone the wheel becomes to damage (it's a lot closer to the street).
The offset measurement of a wheel determines how far it sticks out from the hub. The more offset, the farther the wheel will extend from the hub. It you select a wheel with too much offset the wheel will protrude too far from the wheel well and your tires will rub on the fenders. To little and you'll have clearance issues with the brake calipers. Finding a set of wheels with the right offset is critical in selecting a wheel that looks right and functions correctly.
Offset is the measurement from the centerline of the wheel width to the hub mounting surface. For example, an offset of +59mm means that the distance from the centerline of the wheel to the hub mounting position is 59mm and that 1/2 of the width + 59mm protrudes beyond the hub. An offset of -59mm indicates that 1/2 of the width + 59mm protrudes. "Deep dish" wheels generally have a negative offset. All of the proper offsets for S2000 wheels are positive so for all offset measurements quoted in this article you should assume them to be positive (+).
10-23-2005 | 11:42 PM
#7
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Joined: Dec 2004
Posts: 99
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From: htown
Originally Posted by LubedKoala,Oct 9 2005, 01:18 PM
Would be nice to add offsets and tires sizes to this thread as well. Like what offsets allow you to get maximum tread width without rubbing and so forth. Great write up btw!
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04-11-2006 | 09:51 PM
#8
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Joined: Dec 2005
Posts: 3,227
Likes: 3
From: Tallahassee, FL
^^^ That subject has been covered a million times, and is even a sticky in one of the subforums. It is very hard to be exact though because you can always change your camber or modify your fenders to fit.
Good article on wheel manufacturing, too bad that most manufacturers don't list how their wheels are made unless they are forged (top $). I would like to find out the ways a couple of companies manufacture their wheels -- for instance, ADA has an information-sharing contract with BBS, but I don't know if that means that ADA uses the same procedures as BBS. Falken makes great tires and is a Japanese company, yet they don't run their own wheels on any of their competition cars, which leads me to believe their wheels aren't that great. Just adding some fuel to this post, anybody have any answers?
Good article on wheel manufacturing, too bad that most manufacturers don't list how their wheels are made unless they are forged (top $). I would like to find out the ways a couple of companies manufacture their wheels -- for instance, ADA has an information-sharing contract with BBS, but I don't know if that means that ADA uses the same procedures as BBS. Falken makes great tires and is a Japanese company, yet they don't run their own wheels on any of their competition cars, which leads me to believe their wheels aren't that great. Just adding some fuel to this post, anybody have any answers?
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