Method and device in nodes used for wireless communications. A node receives first information, the first information being used to determine X candidate formats; transmits a first signal, the first signal using a first format; and transmits a second signal, the second signal using a second format; the first format is one of the X candidate formats, and the second format is also one of the X candidate formats; a first timing offset value is used to determine a transmission timing for the first signal, while a second timing offset value is used to determine a transmission timing for the second signal, where the first timing offset value is unequal to the second timing offset value; the first format relates to the first timing offset value while the second format relates to the second timing offset value. The present disclosure improves the random access performance.