Rim (wheel): Difference between revisions
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* Diameter (effective): distance between the bead seats (for the tire), as measured in the plane of the rim and through the axis of the hub which is or will be attached, or which is integral with the rim. |
* Diameter (effective): distance between the bead seats (for the tire), as measured in the plane of the rim and through the axis of the hub which is or will be attached, or which is integral with the rim. |
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* Width (effective): separation distance between opposed rim flanges. |
* Width (effective): separation distance between opposed rim flanges. The flange-to-flange width of a rim should be a minimum of three-quarters of the tire section width. And the maximum rim width should be equal to the width of the tire thread. |
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* Type: Depends on the type of vehicle and tire. There are various rim profiles, as well as the number of rim components. |
* Type: Depends on the type of vehicle and tire. There are various rim profiles, as well as the number of rim components. |
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One-piece rim and wheel assemblies (see image) may be obtained by [[casting]] or [[forging]]. |
One-piece rim and wheel assemblies (see image) may be obtained by [[casting]] or [[forging]]. |
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==Rim Testing== |
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Being a part of a vehicle, rims are subject to high load, which is why their [[durability]] is of utmost importance for the safe driving. Therefore, all rims are supposed to be examined for both [[fatigue]] resistance and strength. As a rule, custom rims<ref name="Custom Rims">[http://www.carid.com/custom-wheels.html Custom Rims], CARiD.com. Custom Car Wheels. Retrieved 2011-09-29.</ref> are subject to the following tests: |
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* [[Endurance]] test - to examine durability and fatigue resistance of a rim, the tire on the test rim is rotated under high pressure. The test is sometimes conducted adding side force and giving camber angle. |
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* Impact Test - in case of the impact test, the wheel collides with a large obstacle to assess the full impact. |
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* Rim [[flange]] test - the flange is tested by applying a load from an arm mounted to the hub. While the tested rim rotates, a bending moments is applied. |
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* Other tests - to check the quality of a rim they provide a lot of other tests, including rim contour/dimensional checks, corrosion [[evaluation]], and coatings analysis. |
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==Life Span of a Rim== |
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Even thought we tend to think that it is quite possible to use a wheel until it rusts away, a limit to the useful life of a wheel and its rim does exist. If a rim is used in severe conditions (e.g., racing of rallying) a hidden damage may be caused. Definitely, it may result in a sudden rim [[failure]] and eventually in an accident. The life span of a rim depends on the using conditions. Normally, a rim lasts longer that a tire. Still when a tire is replaced, it's recommended to examine the rim. And in case any damage (rust, cracks, etc.) is found the whole wheel should be replaced. |
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==Meaning== |
==Meaning== |
Revision as of 10:53, 29 September 2011
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/53/AluminumWheel_spoke_design.jpg/220px-AluminumWheel_spoke_design.jpg)
The rim of a wheel is the outer circular design of the metal on which the inside edge of the tire is mounted on vehicles such as automobiles.[1] For example, on a bicycle wheel the rim is a large hoop attached to the outer ends of the spokes of the wheel that holds the tire and tube.
In the 1st millennium BC an iron rim was introduced around the wooden wheels of chariots.
Characteristics
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Scratched_rim_on_one-piece_wheel.jpg/220px-Scratched_rim_on_one-piece_wheel.jpg)
- Diameter (effective): distance between the bead seats (for the tire), as measured in the plane of the rim and through the axis of the hub which is or will be attached, or which is integral with the rim.
- Width (effective): separation distance between opposed rim flanges. The flange-to-flange width of a rim should be a minimum of three-quarters of the tire section width. And the maximum rim width should be equal to the width of the tire thread.
- Type: Depends on the type of vehicle and tire. There are various rim profiles, as well as the number of rim components.
- Modern passenger vehicles and tubeless tires typically use one-piece rims with a “safety” rim profile. The safety feature helps keep the tire bead held to the rim under adverse conditions by having a pair of safety humps extending inwardly of the rim toward the other tire bead seat from an outer contoured surface of the rim.[2]
- Heavy vehicles and some trucks may have a removable multi-piece rim assembly consisting of a base that mounts to the wheel and axle. They then have either a side ring or a side and lock ring combination. These parts are removable from one side for tire mounting, while the opposite side attached to the base has a fixed flange.
- Vehicle performance: Because the rim is where the tire resides on the wheel and the rim supports the tire shape, the dimensions of the rims are a factor in the handling characteristics of an automobile. For example:
- Overly wide rims in relation to the tire width for a particular car may result in more vibration and less comfortable ride because the sidewalls of the tire have insufficient curvature to flex properly over rough driving surfaces. Oversized rims will cause the tire to rub when turning.
- Overly narrow rims in relation to the tire width may cause poor handling as the tire may distort sideways under fast cornering. On motorcycles, a narrow rim will alter the tire profile, concentrating tire wear in a very small area during cornering, with a smaller contact patch during braking.[3]
- On bicycles, the optimum tire width is approximately twice the rim's internal width (e.g. a 35mm tire on a rim with an ETRTO 17mm internal width) or one-and-a-half times the rim's external width.[citation needed] Considerable variation outside this range is safe, but very wide tires on a narrow rim can overstress the rim and damage the tire sidewalls, whereas very narrow tires on a wide rim give a hard ride and can result in a high-pressure tire blowing off.
Production
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/BentRim.jpg/220px-BentRim.jpg)
A standard automotive steel wheel rim is made from a rectangular sheet metal. The metal plate is bent to produce a cylindrical sleeve with the two free edges of the sleeve welded together. At least one cylindrical flow spinning operation is carried out to obtain a given thickness profile of the sleeve — in particular comprising in the zone intended to constitute the outer seat an angle of inclination relative to the axial direction. The sleeve is then shaped to obtain the rims on each side with a radially inner cylindrical wall in the zone of the outer seat and with a radially outer frusto-conical[4] wall inclined at an angle corresponding to the standard inclination of the rim seats. The rim is then calibrated.[5]
To support the cylindrical rim structure, a disc is made by stamping a metal plate. It has to have appropriate holes for the center hub and lugnuts. The radial outer surface of the wheel disk has a cylindrical geometry to fit inside the rim. The rim and wheel disk are assembled by fitting together under the outer seat of the rim and the assembly welded together.[5]
One-piece rim and wheel assemblies (see image) may be obtained by casting or forging.
Rim Testing
Being a part of a vehicle, rims are subject to high load, which is why their durability is of utmost importance for the safe driving. Therefore, all rims are supposed to be examined for both fatigue resistance and strength. As a rule, custom rims[6] are subject to the following tests:
- Endurance test - to examine durability and fatigue resistance of a rim, the tire on the test rim is rotated under high pressure. The test is sometimes conducted adding side force and giving camber angle.
- Impact Test - in case of the impact test, the wheel collides with a large obstacle to assess the full impact.
- Rim flange test - the flange is tested by applying a load from an arm mounted to the hub. While the tested rim rotates, a bending moments is applied.
- Other tests - to check the quality of a rim they provide a lot of other tests, including rim contour/dimensional checks, corrosion evaluation, and coatings analysis.
Life Span of a Rim
Even thought we tend to think that it is quite possible to use a wheel until it rusts away, a limit to the useful life of a wheel and its rim does exist. If a rim is used in severe conditions (e.g., racing of rallying) a hidden damage may be caused. Definitely, it may result in a sudden rim failure and eventually in an accident. The life span of a rim depends on the using conditions. Normally, a rim lasts longer that a tire. Still when a tire is replaced, it's recommended to examine the rim. And in case any damage (rust, cracks, etc.) is found the whole wheel should be replaced.
Meaning
The terms "wheel" and "rim" are often used synonymously, as in decorative wheels being called rims. Some authors are careful to use "rim" for only the outer portion of a wheel, where the tire mounts,[7] just as the rim of a coffee cup or a meteor crater does not refer to the entire object. Others use "rim" to mean the entire metal part to which the tire mounts,[8] because the rim and the wheel are often cast or stamped from a single piece of metal instead of being distinct as with wire wheels. At the same time, "wheel" may refer to the entire rotating assembly, including the tire.[9]
Railroad usage
In railroad usage the conical running surface of the wheels may be called a rim or a tyre.
See also
References
- ^ "Rim" as defined by the Dictionary of Automobile Terms, undated, accessed on 2008-06-04.
- ^ Wheel Rim European Patent 6 June 2007, retrieved on 2008-06-13.
- ^ Dunlop Tire Tips, undated, retrieved on 2008-06-13.
- ^ Definition of "frustoconical" in Wiktionary, retrieved on 2008-06-16.
- ^ a b Vehicle wheel with assembly under the rim seat, US Patent 6935704, Issued on August 30, 2005, retrieved on 2008-06-13.
- ^ Custom Rims, CARiD.com. Custom Car Wheels. Retrieved 2011-09-29.
- ^ Walker, Rob. (June 17, 2007). "Donk my ride". The New York Times. Retrieved 2008-06-13..
The second trend is rim inflation, the ... popularity of increasingly large wheels ...
{{cite web}}
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(help) - ^ "rim, a. The peripheral portion or outer ring of a wheel". Oxford University Press. Retrieved 2011-03-27.
2009 Miami Herald (Nexis) 19 Feb. 8 The rims and tires were taken off a 2006 Ford...and the car was left mounted on bricks.
- ^ Sean Bennett (2010). Heavy Duty Truck Systems. Cengage Learning. pp. 855–856. ISBN 9781435483828. Retrieved 2011-03-27.
The term wheel may be used in several ways...