The Wheel Fitment, Tyre Stretch, Rolling Radius and Speedometer Error Calculator

Insert your existing wheel and tyre specs, and the desired size, and the outcome is shown on the diagram.

Your existing setup

Existing Tyre
Existing Wheel

Your new setup

New Tyre
New Wheel
Your Results

Existing

New

Diameter
621.2mm
634.3mm
Circumference
1951.6mm
1992.7mm
Poke
35.9mm
50.3mm
Inset
141.9mm
140.3mm
Speedo error
0%
-2.07%
Reading at 30mph
30mph
29.38mph
Reading at 60mph
60mph
58.76mph
Ride height gain
0mm
6.55mm
Arch gap loss
0mm
6.55mm
Wheel Fitment Guide

Compared to your existing wheel, this new wheel will have an inner rim which is 1.6mm further away from the suspension strut. The outer rim will poke out 14.4mm more than before.

The strut shown in the diagram is for show only. Don't worry if the wheel looks like it fouls!

Bear in mind most tyre manufacturers vary slighty from the specs, and that it could be dangerous to run tyres on wheels they aren't designed to fit.

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17x7.5 ET45 wheel options
WORK Wheels
SSR Wheels
JR Wheels
Rotiform Wheels
Rota Wheels
Bola Wheels
Fuel Wheels
3SDM
Concaver
7Twenty
BBS
1Form
Niche
Autostar
Dare
Motegi
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