Toyota explains the genius behind its iQ - Part 1

In a series of six simple cut-paste-and-print guides, Toyota will explain how.

INNOVATION No1: The front-mounted differential


The position of the gearbox differential dictates the position of a car's driven wheels and is traditionally a limiting factor on how space under the bonnet can be used. Toyota's brainwave was the simple but highly effective idea of moving the differential in front of the engine, a concept that opens up new and radical opportunities for iQ's small-but-spacious design.

This clever piece of engineering brings three key advantages:

1. The space under the bonnet can be made more compact.

2. The front wheels can be positioned at the far corners of the car, with almost no front overhang.

3. The length of the cabin can be extended, without increasing the car's overall size. iQ's interior gains an additional 120mm compared to the Toyota Yaris.


Installing the differential so far forward reduces the distance from the front edge of the bumper to the accelerator pedal, allowing more space in the passenger compartment.

By moving the large, 15-inch alloy wheels further out to the corners of the car and minimising the front overhang, iQ gains a distinctive "super stance". This firmly planted look broadcasts the car's great stability and a fun-to-drive character, qualities far in advance of the traditionally modest dynamic performance of small city cars.

Coming soon: Innovation No2: The Centre Take-Off Steering Gear.