Can we make tayammum and pray when we have some drinking water (enough to make wudu) in a journey? What is the ruling when that water is not sufficient to make wudu?
Wudu can be made by only once (washing) instead of three times. It is proved that the Prophet, peace be upon him, made wudu once, twice or three times (and three times is best). So if water is not enough to wash wudu parts once, then you can make tayammum.