O selim está demasiado baixo.

Selim usually means a saddle, especially a bicycle saddle or a similar narrow seat. It is more specific than a general seat.

So in this sentence, o selim most naturally refers to the saddle of a bike rather than just any chair or seat.

O is the definite article, meaning the. It suggests we are talking about a specific saddle that both speaker and listener know about.

• O selim está demasiado baixo. = The saddle is too low.
• Um selim está demasiado baixo. = A saddle is too low.

In real conversation, o is more natural when talking about a particular bike saddle in front of you.

Portuguese often uses estar for states or conditions that can change, and ser for more permanent or defining characteristics.

Here, the saddle being too low is a changeable position. You can raise or lower it. So estar is the right verb:

• O selim está demasiado baixo. = its current position is too low.

Using ser here would sound wrong because the saddle is not inherently or permanently low; it is just set too low at the moment.

This is an important difference:

• demasiado baixo = too low
• muito baixo = very low

So demasiado expresses excess: lower than it should be.

Examples:

• O selim está muito baixo. = The saddle is very low.
• O selim está demasiado baixo. = The saddle is too low.

In European Portuguese, demasiado is a very natural way to say too.

Because baixo agrees with selim, which is a masculine singular noun.

• o selim → masculine singular
• so the adjective is baixo

If the noun were feminine, you would use baixa:

• A cadeira está demasiado baixa. = The chair is too low.

No. Baixo can have several related meanings depending on context, such as:

• low in height or position
• short for a person
• quiet/low for sound

In this sentence, because we are talking about a saddle, baixo clearly means low in position.

Yes, this is the normal word order.

In Portuguese, an adverb like demasiado usually comes before the adjective it modifies:

• demasiado baixo = too low
• muito alto = very high

So está demasiado baixo is the standard structure for is too low.

In European Portuguese, selim is pronounced approximately like suh-LEEN, but with a very reduced first vowel and a nasal ending.

A rough guide:

• se- is often very weak in European Portuguese
• -lim ends with a nasal sound, not a fully pronounced English m

So it is closer to s'LEEN with nasalization than to a fully clear seh-leem.

Sometimes, but they are not exactly the same.

• selim = saddle, especially on a bicycle
• assento = seat, seating place, seat part in a more general sense

If you are talking about a bike saddle, selim is the best word. Assento would sound more general and less precise.

Yes, it sounds natural in European Portuguese, especially when talking about adjusting a bicycle.

A few natural alternatives are also possible, depending on tone and context:

• O selim está demasiado baixo.
• O selim está muito baixo. = The saddle is very low.
• Tens o selim demasiado baixo. = You have the saddle too low.

That last version is also very common in everyday speech when commenting on someone’s bike setup.