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Wheel Upsteps

Get Secure Wheel Replacement Options Derived from Factory Sizes

Retrieve a comprehensive list of potential rim and tire combinations that align with the original equipment (OE) wheel specifications. Our system ensures that any options unavailable in the current tire market are excluded from the results. Demo and example of usage is available at Rim & Tire Size Calculator Page: https://www.wheel-size.com/calc/

Parameters:

  • OE Rim Specification: Example - 17 ⨯ 7J ET45
  • OE ISO Metric Tire: Example - 225/55 R17
  • Adjustment Steps: Define the number of steps to calculate either in the positive range (0 to 3) or negative range (-3 to 0). The default is set at +2.
  • Tire Section Width: Specify the relative difference, ranging from 0% to 25%. The default is set at 10%.
  • Tire Overall Diameter: Indicate the relative difference, which can be between 0% and 15%. The default is set at 5%.

Assumptions:

  • The Steering-axis Inclination (SAI), also known as the kingpin inclination angle, is assumed to be 18 degrees.
  • The Camber Angle is presumed to be 2 degrees, with a consistent camber factor of 1 across all nominal aspect ratios.

Calculation Process:

Our system methodically examines rim diameters based on the steps parameter provided. It then assesses all possible combinations of aspect ratios and section widths available in the market.

The primary objective is to determine the difference in tire dimensions between the OE and the current iteration. If the resulting difference remains within the permissible tolerance (defined by s_max for section width and do_max for overall diameter), our system then identifies the wheel rim compatible with the tire in question.

For these identified wheel rims, the offset value is meticulously chosen to ensure that the scrub radius mirrors that of the OE wheel rim.

Reference Materials:

  • ISO 4000-1 (11 edition) Passenger car tyres and rims / Tyres (metric series)
  • ISO 4000-2 (5 edition) Passenger car tyres and rims / Rims
  • ISO 8855 (2 edition) Road vehicles / Vehicle dynamics and road-holding ability
get/v2/upsteps/

Query parameters

rim_diameternumber double required
Example:18

Rim diameter is the distance measured in inches across the face of the wheel, from bead seat to bead seat. (e.g. 19)

rim_widthnumber double required
Example:7.5

Rim width is the distance measured in inches from bead seat to bead seat. (e.g. 7.5)

rim_offsetnumber double required
Example:35

Rim offset is a distance between wheel mounting surface where it is bolted to hub and the centerline of rim. (e.g. 38)

section_widthinteger required
Example:235

Section width is the width of the tire in mm. (e.g. 225)

aspect_ratiointeger required
Example:60

The Aspect ratio is indicated on the tire sidewall as a percentage. It's the height of the sidewall measured from wheel rim to top of the tread, expressed as a percentage of tire width. (e.g. 45)

stepsinteger

How many steps for plus/minus rim diameters iterate

s_maxinteger

Tire section width relative difference, % (e.g. 10)

do_maxinteger

Tire overall diameter relative difference, % (e.g. 5)

Response

Changes

No recorded changes to this endpoint across all 1 revision of this API.