Iāve noticed that different time signatures and strumming patterns has a āmaximumā bpm. For instance, 4/4 with something around 250 bpm doing a simple down and up strokes is possible to play, correct? But with 4/4 16th is way too fast to play, impossible I suppose. I guess that applies to every time signatures. So thereās a maximum bpm with all the strumming pattern that exists?
Yes I edit the post a lot, sadly Iām a perfectionist.
Some strumming patterns, especially those where you strum 16th notes become increasingly difficult in higher tempo. Also they might become too busy.
I havenāt put much thought to it before and I donāt believe there are written rules. Some strumming patterns sound best in certain tempo ranges. And youād need to change them if you change the tempo. Depending what the song requires really.
Awesome, thank you 
What do you mean by ābecome too busyā?
Ah sorry for not going into further details on this term. I am sure others will find a better way/words to explain this.
In this context itās when too many notes/rhythms are played making music sound too much dense. Hope this makes sense.
Maybe an obvious example would be if strumming a pattern with many strums on the 16th notes when the vocals have slower changes. Then it wouldnāt fit the song and you could say that the rhythm guitar playing is too busy. Or when a lead guitarist keeps soloing over the singer. Or if strumming leaves no space to hear phrases.
I seeā¦ I was suspecting this term meaning ātoo muchā and it seems to be correct
Definitely no need to be sorry 
For rhythm/strumming exercises you will very rarely set a metronome faster than about 120bpm. For solo picking, ie playing notes not strumming, you might set a faster speed but that would only be for certain genres such as jazz or heavy metal. 250bpm is insanely fast.
unless you play with ukulele people
What?
@nadimz @chris_m Iām a beginner and I donāt know much of music theory. If I want to set a time signature on the metronome (instead of a single click, 1/1) to practice 16th strumming, what it would be? I guess in this case itās still 4/4 and all the strumming movements will happen between the four beats without the metronome display or click 16 times, itāll always only show 4 beats no matter the amount of strumming, right? Just like with all down and ups D U D U D U D U, itās eight strumming movements but only 4 beats and the metronome will show and click only 4 times. Whatās this called by the way, 4/4 8th strumming?
And I guess that applies to other time signatures, like 6/8, 3/4ā¦? No matter how much strumming, the time signature stays the same?
Iām not an english native speaker so I hope that Iāve written correctly. My english is always a work in progress
ukulele people like to play FAST. 250 bpm is not uncommon for them.
Renan, I am not a native English speaker neither and your English more than fine.
Although related to time signatures. Practicing strumming 8th or 16th beat doesnāt mean you need to change the time signature.
Tempo, which normally is specified as beats per minutes (BPM) will tell you how many beats per minute there are. But it doesnāt tell you how many beats there are in a bar/measure (time signature).
In the popular 4/4 time signature, there are 4 beats (referred to as down beats many times) in a measure. Counting beats would be 1 2 3 4 1 2 3 4. In a 3/4 time signature, there are 3 beats in a measure, counting 1 2 3 1 2 3.
Metronome will click every down beat.
In a 4/4 time signature, if you down strum every down beat, then you are strumming every 1/4 beat. If you add a up strum un between, then this would be a strum on an 8th beat.
If instead of counting 1 2 3 4 1 2 3 4, you count 1 & 2 & 3 & 4 & 1 & 2ā¦ then uo strums would land on the & counts.
The tempo hasnāt changed. Neither did the time signature. You are just playing on more beats.
If you know count 1 e & a 2 e & 3 e & a 4ā¦ Then strumming on the āeā or āaā would be on 16th notes.
Again, tempo and signature hasnāt changed.
Itās a very useful practice to put the metronome and just count these variations to get used to the intervals. The youād try strumming as well.
As I said, the metronome only tells you the tempo.
Some metronomes will put an accent (make it sound louder or a different pitch) on the first beat in the measure. So, in that case the metronome tells you when the measure starts and by doing so tells you the time signature. Basic metronomes that do this only support 4/4 measure and will put an accent on the first beat of every 4. If you get a metronome that supports various time signatures than using this same method it could tell you when the measure starts in that time signature.
@RenanRischiotto
Try using the Strumming Machine on the web site to practice different strummjng patterns. I think it will also help you understand time signatures
Ah ok