Wheel Sizes

This example calculates the theoretical OD of wheels given common measurement parameters:

These calculations were used to determine how much higher my 91S19 would sit with larger wheels. Three options include upgrade costs and references.

Contents

Helper function to do the math.

CalcOD = @(BW,AR,RD) RD+2*AR*BW/25.4;

Baseline: 98D19 stock wheels (14" LRC 1760#)

The 98D19 had 205/75-14 tires.

od14c = CalcOD(205,0.75,14)

od14c =
       26.106

Current: 91S19 stock wheels (13" LRC 1360#)

The 91S19 currently has 175/80-13 tires.

od13c = CalcOD(175,0.8,13)

od13c =
       24.024

Option 1: 13" LRD replacements (1730#)

Believe it or not Carlisle makes a 8-ply bias-ply D-load-rated Sure Trail tires that fit stock 13" rims.

od13d = CalcOD(185,0.8,13)

od13d =
       24.654

IncreasedHeight = (od13d-od13c)/2 %in

IncreasedHeight =
      0.31496

Upgrade cost (two new tires only)

NewTire = 85; %mounted on same rims
CostD13s = 2*NewTire

CostD13s =
   170

Upgrade costs do not include tax.

Source:

Option 2: 15" LRC replacements (1840#)

od15c = CalcOD(205,0.75,15)

od15c =
       27.106

IncreasedHeight = (od15c-od13c)/2 %in

IncreasedHeight =
       1.5413

Upgrade cost (fits existing hubs, three new wheels - spare must match)

NewWheel = 120; %same 5 on 4.5" pattern
CostC15s = 3*NewWheel

CostC15s =
   360

Upgrade costs do not include shipping, handling, etc.

Source: http://www.NorternTool.com

Option 3: 15" LRD replacements (2540#)

od15d = CalcOD(225,0.75,15)

od15d =
       28.287

IncreasedHeight2 = (od15d-od13c)/2 %in

IncreasedHeight2 =
       2.1319

Upgrade cost (requires new hubs and brakes, three new wheels)

NewWheel = 145; %each: 6-hole rims
NewDrums = 80; %pair: 5 on 5.5" pattern, requires 12" brakes
NewBrakes = 140; %pair: 12" complete set
CostD15s = 3*NewWheel + NewDrums + NewBrakes

CostD15s =
   655

Upgrade costs do not include shipping, handling, etc.

Source: http://www.NorternTool.com

Summary

Published with MATLAB® 7.9