Minimum Control Speed on the Ground: VMCG
JAR 25.149 Subpart B FAR 25.149 Subpart B / JAR/FAR 25.149
VMCG, the minimum control speed on the ground, is the calibrated airspeed during the take-off run, at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the aeroplane with the use of the primary aerodynamic controls alone
(without the use of nose-wheel steering) to enable the take-off to be safely continued using normal piloting skill.
In the determination of VMCG, assuming that the path of the aeroplane accelerating with all engines operating is along the centreline of the runway, its path from the point at which the critical engine is made inoperative to the point at which recovery to a direction parallel to the centreline is completed, may not deviate more than 30 ft laterally from the centreline at any point.”
VMCG must be established, with:
The aeroplane in each take-off configuration or, at the option of the applicant, in the most critical take-off configuration;
Maximum available take-off power or thrust on the operating engines;
The most unfavourable centre of gravity;
The aeroplane trimmed for take-off; and
The most unfavourable weight in the range of take-off weights.”
Below Vmcg, I guess you're a test pilot and do what ever it takes, including Nosewheel steering usage.
