What is the standard for wheel rim sizes and offsets in electric vehicles?

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Discussion Overview

The discussion revolves around the standards for wheel rim sizes and offsets specifically in the context of electric vehicles, particularly for a BLDC hub motor designed for a light vehicle. Participants explore various dimensions, bolt patterns, and the implications of offsets on wheel design.

Discussion Character

  • Technical explanation
  • Exploratory
  • Debate/contested

Main Points Raised

  • One participant seeks clarification on standards for rim dimensions, including the contact area between rim and tire, bolt patterns, and load-bearing capacities.
  • Another participant provides a link to a resource on SAE wheel standards, suggesting that there are established guidelines available.
  • A participant mentions specific standard rim sizes for various tire dimensions, indicating a relationship between tire size and rim width.
  • Concerns are raised about the acceptable offsets for wheel rims, with references to the need for a positive offset to conceal the motor in the design.
  • There is an inquiry about the availability of CAD models for specific rim sizes, indicating a need for practical design resources.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the existence of comprehensive standards for rim sizing and offsets. While some standards are mentioned, there is no consensus on the specifics or completeness of the information available.

Contextual Notes

The discussion highlights potential limitations in the availability of standardized information regarding rim dimensions and offsets, as well as the dependence on specific vehicle designs and applications.

RKD89
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Hi,

I am designing a BLDC hub motor for an electric buggy/light vehicle.
The wheels are sized as 13" (total outer diameter), 3" wide.
A standard 8" wheel rim should fit in well, width of the rim would be 2.10".
Are there any standards for rims dimensions: The contact area between rim and tire, no. and PCD of bolts, etc

By studying some rims online I was able to conclude that four 11 mm bolts at a P.C.D. of 100 mm or about 4 " is common. But is the standard? I can always check them for strength/load bearing capacity but surely there must be some standard guiding the process.
Also the hub of the wheel rim should be exactly in the centre of wheel, or can there be offsets allowed
(http://www.discounttire.com/dtcs/infoWheelOffsets.do )
The above link says offsets are possible. Just going through certain wheels of Audi, Benz etc shows most cars have offsets.
I would like to have a positive offset based on the above link to hide the motor. How much offset can I have?

I have standards for how a wheel should be test. There must be some other standards for wheel rim sizing, shape of the rim in which a tire would fit etc. I just can't find them online.
It'll be great if someone can point me in the right direction. Or a CAD model of 8" by 2.10" wheel rim will also be helpful (fits a 3.00 x 8 size tire).

Thanks in advance
 
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Thank you so much
 
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Standard rim sizes incorporate 5.5 inches for P195/75R15 tires, 6 inches for P215/75R15 tires, 6.5 inches for P235/75R15 tires, 7 inches for P225/50R15 tires and 7.5 inches for P225/45R17 tires. The measuring rim width of a tire increments by .5-creep augments in extent to increments in the tire segment width.

The measuring rim width of a tire, additionally called the plan rim width, decides the width of the tire. The outline rim width is a global standard of measure that all tire makers use to guarantee that the tires they deliver have similar measurements in respect to their physical sizes. Bigger tires ordinarily have more extensive wheel widths, while littler tires have contract wheel widths.
 
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