# Fourth gear does nothing, and that's the whole chart

> A gear ratio table looks like five rows of numbers. Read the gaps between the rows instead and it turns into a picture of what the gearbox was built to spend its time doing.

August 19, 2026 · https://justog.club/stories/gear-ratio-chart

Five rows. A ratio in one column, a speed at a fixed engine speed in the other. First is 3.36,
fifth is 0.82, and the row in between them does the interesting thing.

Fourth gear reads 1.00. In fourth, the gearbox isn't doing anything at all.

## What does a ratio of 1.00 actually mean?

That the input shaft and the output shaft are turning at exactly the same speed.

Every other ratio on the table describes gearing down — the engine spins faster than the wheels,
trading speed for torque so the car can get moving and keep accelerating without the engine
labouring. At 1.00 there's no trade happening. Input equals output, direct drive, nothing between
the engine and the propshaft but a straight-through connection.

It's the one row that isn't really a ratio at all. It's the absence of one, and everything else on
the chart is measured against it.

## Why is first so much bigger than second?

Because first only has one job, and it's the hardest one.

3.36 down to 1.81 is a drop of almost half, the largest jump on the whole table. First gear has to
move a stationary car from nothing, which needs far more mechanical advantage than any gear that
follows it — by second, the car's already moving and the job has changed from starting it to
keeping it accelerating.

## Why does the size of the jump shrink as the gears go up?

Because each gear is picking up a job the last one already started.

Second to third is a smaller step than first to second. Third to fourth is smaller again. By the
time you reach fourth to fifth — 1.00 down to 0.82 — the change is the smallest on the chart. The
work of getting a car moving is front-loaded into the low gears; the work of cruising it barely
needs any gearing at all, which is exactly what a ratio close to 1.00 tells you.

Read that way, the table stops being five numbers and becomes a shape: steep at the start,
flattening out toward the end.

## Why is fifth printed in red?

Because 0.82 isn't a gear for going faster. It's a gear for going quieter.

Below 1.00 the gearbox is overdriving — the output shaft turns faster than the input, so the
engine turns slower than it would in direct drive at the same road speed. 130mph at 4000rpm in
fifth against 107mph at the same 4000rpm in fourth isn't really about a higher top speed. It's
about the engine doing less work, and burning less fuel, at whatever speed the car is actually
travelling. The red ink is marking the one row where the logic of the whole table flips.

## Can these figures belong to a real gearbox?

The ratios themselves are just numbers a designer chose — nobody owns a fraction.

What's licensable is the manufacturer's name on the box that ratio set came out of, and the model
it was fitted to. If a real car's real gearbox is the point of the shirt, that permission is part
of commissioning it. If it isn't the point, an invented set is better anyway, because it can be the
exact set from the exact car somebody actually owned, rather than a stock figure printed on ten
thousand others.

## Does this chart mean anything on an automatic or an EV?

Less, and for a genuine reason rather than a fashion for manuals.

An automatic hides the table behind a torque converter and a computer choosing the ratio for you;
a single-speed EV motor has no table at all, because it doesn't need one. This chart is specific to
a car where a person moves a lever and decides. That's not nostalgia for the shirt — it's a real
description of a different kind of machine, and the [wiring inside one of the electrical ones is
its own document](/stories/wiring-loom-colour-code) rather than this one.

## Does it work for a different car, or a bike, or a bicycle?

Any geared drivetrain has a version of this table, and most of them are worth printing.

A motorcycle gearbox has the same shape, usually with a steeper first gear again for getting a
lighter machine off the line. A bicycle's cassette and chainring combination is the same idea
stretched across more rows. Anyone who's actually counted their own gear-inches has a specific set
of numbers worth putting on a shirt, in the same way a [chart of intervals from a lubrication
diagram](/stories/lubrication-chart-fold-out) is worth having if you know the machine.

## Does it print well?

Yes — it's a table, which is one of the most reliable things to put on fabric.

Two colours, flat fields, hard rule lines. Cream for the ratios and speeds, red for the one row
that needs to stand apart, on a dark green or charcoal ground that reads as workshop rather than
decoration. Keep the numerals large enough to survive the weave rather than shrinking them to match
a real spec sheet; five rows means there's room to set them generously.

## How do I get one made?

Describe the box at [JustOG](/) — the ratios, the speeds, and which row should carry the colour.
Pick a direction, drag the crop frame, see it composited on the real garment, and it's made to
order and shipped.

Designs other people have published are in the [shop](/shop).

Five rows, one of them doing nothing, and that's the row the whole chart is built around.