Road speed is engine speed, divided down by the gearbox and the final drive, then multiplied by how far the tire rolls in one turn. Nothing slips in this model, so it is exact for a locked clutch and a tire that is not spinning.

v = \frac{n \times C}{i_g \times i_f} \qquad C = \pi D

$n$ : engine speed in rpm.
$i_g$ : the selected gear ratio, and $i_f$ : the final-drive (differential) ratio.
$C$ : rolling circumference of the driven tire, from its diameter $D$ .

With $C$ in metres the result is metres per minute. Multiply by 0.06 for km/h:

v_{\text{km/h}} = \frac{0.06 \; n \; C_{\text{m}}}{i_g \, i_f}

Tire diameter from the sidewall code

D = 25.4 \times d_{\text{rim}} + 2 \times W \times \frac{AR}{100}

Reading the gear chart

Each dashed ray is one gear: speed rises in proportion to rpm. The solid sawtooth shows an upshift at redline. The engine drops to a lower speed that depends only on the ratio between neighbouring gears:

n_{\text{after}} = n_{\text{redline}} \times \frac{i_{g+1}}{i_g}

Closely spaced ratios give small drops and keep the engine in its power band. Wide ratios give relaxed cruising but bigger gaps.

v = \frac{n \times C}{i_g \times i_f} \qquad C = \pi D

$n$ : engine speed in rpm.
$i_g$ : the selected gear ratio, and $i_f$ : the final-drive (differential) ratio.
$C$ : rolling circumference of the driven tire, from its diameter $D$ .

With $C$ in metres the result is metres per minute. Multiply by 0.06 for km/h:

v_{\text{km/h}} = \frac{0.06 \; n \; C_{\text{m}}}{i_g \, i_f}

Tire diameter from the sidewall code

D = 25.4 \times d_{\text{rim}} + 2 \times W \times \frac{AR}{100}

Reading the gear chart

n_{\text{after}} = n_{\text{redline}} \times \frac{i_{g+1}}{i_g}

Closely spaced ratios give small drops and keep the engine in its power band. Wide ratios give relaxed cruising but bigger gaps.

Gear	Ratio	Overall	km/h / 1000 rpm	Max km/h	RPM after upshift
1	3.15	12.92	9.3	65	4,556
2	2.05	8.41	14.2	100	5,054
3	1.48	6.07	19.7	138	5,534
4	1.17	4.80	24.9	174	5,803
5	0.97	3.98	30.1	210	5,845
6	0.81	3.32	36.0	252	—

Gear	Ratio	Overall	km/h / 1000 rpm	Max km/h	RPM after upshift
1	3.15	12.92	9.3	65	4,556
2	2.05	8.41	14.2	100	5,054
3	1.48	6.07	19.7	138	5,534
4	1.17	4.80	24.9	174	5,803
5	0.97	3.98	30.1	210	5,845
6	0.81	3.32	36.0	252	—

Speed, RPM & Gearing

Inputsdrag · tap · type

Read-off point

Tire

Transmission

Fig. 07Gear chart and instruments

§ How it works

Tire diameter from the sidewall code

Reading the gear chart

Speed, RPM & Gearing

Inputsdrag · tap · type

Read-off point

Tire

Transmission

Fig. 07Gear chart and instruments

§ How it works

Tire diameter from the sidewall code

Reading the gear chart