Please be safe with the speed, stay in control. Back in the day, the head honchos of step set safe guidelines between 126-140 beats per minute. Those guidelines were set a long time ago. From my experience, the safe range is between 138 - 155 beats per minute.

Personally, I feel anything below 138 will be too slow. You will need the momentum of the speed to make the moves doable, especially scissor and double-time repeaters. Most of the time, slower is actually harder because you lose the benefit of momentum. While the tempo is slow, you can travel in the full range of movement, but again it is harder.

Reversehook classes are usually around 150 beats per minute. Reversehook classes are ADVANCED. This assumes that if you attend regularly, you are very familiar with the cues and moves. Thats what it comes down to, knowing what you are doing and being comfortable.

My advice for new steppers is to set the tempo at 138 and learn to be comfortable with the vocal cueing, use the videos for reference only. The tempo of the videos can be slowed down when you are learning a move. You will find that naturally, you will want to increase the tempo in order to execute a double-time repeater without feeling unbalanced.

When I work out by myself, I typically use 147 or 149 BPM. When I'm writing new choreography, I drop back to 138 BPM. I will turn the BMP to 150 as a test for advanced options.

 As always, give yourself lots of room. Make sure the floor is clear of clutter.

When you need to adjust the tempo of the music, use a speed and pitch app on your mobile device. These apps allow you to change the speed without changing the pitch of the voice and make me sound like a chipmunk in the process. I guess, if that is your intention, you can also do that with these apps too. :)