---
title: "Get Secure Wheel Replacement Options Derived from Factory Sizes"
method: GET
path: "/v2/upsteps/"
tags: ["Wheel Upsteps"]
---

# Get Secure Wheel Replacement Options Derived from Factory Sizes

`GET /v2/upsteps/`

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

## Query parameters

- `rim_diameter` number, double, required
- `rim_width` number, double, required
- `rim_offset` number, double, required
- `section_width` integer, required
- `aspect_ratio` integer, required
- `steps` integer
- `s_max` integer
- `do_max` integer

## Response `200`

- UpstepsReportOutput
  - `data` UpstepsData[], required
    - `tire` Tire, required
      - `designation` string, required — 215/60 R 17
      - `section_width` integer, required — 215
      - `aspect_ratio` integer, required — 60
      - `weight` number, double, required — 26.06
    - `rim` Rim, required
      - `designation` string, required — 17 ⨯ 6.5J
      - `diameter` number, double, required — 17
      - `width` number, double, required — 6.6
      - `offset` integer, required — 43
      - `backspacing` integer, required — 126
      - `weight` number, double, required — 19.18
    - `is_oe` boolean, required — False
    - `difference` Difference, required
      - `s_relative` number, double, required — -7.14
      - `s_absolute` number, double, required — -17
      - `do_relative` number, double, required — 1.47
      - `do_absolute` number, double, required — 10
  - `meta` UpstepsMeta, required
    - `count` integer, required — number of wheels
    - `by_rim` object, required

---

[API](https://skmtc.dev/wheel-size/apis/wheel-fitment-api.md) · [All operations](https://skmtc.dev/wheel-size/apis/wheel-fitment-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/wheel-size/wheel-fitment-api/revisions/8b6863e8004e/schema)