Quin tipus de pneumàtic és aquest?

Quin means which or what kind of when it is used before a singular masculine noun.

In this sentence, it goes with tipus, which is a masculine singular noun:

• quin tipus = what kind / which type

The forms are:

• quin → masculine singular
• quina → feminine singular
• quins → masculine plural
• quines → feminine plural

So it is quin tipus, not quina tipus.

Quin pneumàtic? would mean which tire?, usually when choosing among specific tires.

But quin tipus de pneumàtic? means what type of tire? or what kind of tire?, which asks about the category, not just which individual one.

So:

• Quin pneumàtic és aquest? = Which tire is this?
• Quin tipus de pneumàtic és aquest? = What type of tire is this?

De means of here.

Catalan often uses the structure:

• tipus de + noun = type of + noun

So:

• tipus de pneumàtic = type of tire

This works like many other Catalan expressions:

• mena de cotxe = kind of car
• classe de problema = type of problem

Because Catalan usually does not use an article in this kind of question.

You are asking directly:

• Quin tipus de pneumàtic és aquest?

not

• Quin és el tipus de pneumàtic...?

The version with el is possible in a more specific or heavier structure, but the simple, natural question is the one you have here.

Because this sentence is asking about identity/classification, not location or temporary condition.

Catalan, like Spanish, often distinguishes:

• ser → identity, definition, classification
• estar → location, state, condition

Here you are asking what type it is, so Catalan uses ser:

• és = is

So:

• Quin tipus de pneumàtic és aquest? = What type of tire is this?

In Catalan, demonstratives like aquest (this) can come after the verb in identifying questions like this.

The structure is very natural:

• Quin tipus de pneumàtic és aquest?

Literally, it is close to:

• What type of tire is this?

This final position is normal and idiomatic in Catalan when identifying something.

Aquest means this — something close to the speaker.

Aquell means that — something farther away.

So:

• Quin tipus de pneumàtic és aquest? = What type of tire is this?
• Quin tipus de pneumàtic és aquell? = What type of tire is that?

There is also este in some Valencian usage, but aquest is the standard form learners most often see.

It agrees with tipus, because quin directly modifies tipus.

Structure:

• quin → modifies tipus
• de pneumàtic → tells you type of what

So even though pneumàtic is also masculine singular here, the important point is that quin is linked to tipus.

A helpful approximation is:

• pnew-MAH-tik

A few pronunciation notes:

• pn- at the beginning is unusual for English speakers. In careful speech, both sounds are there, though some learners initially simplify it.
• The accent mark in pneumàtic shows the stress falls on mà:
  • pneumàtic

The word is related to pneumatic in English.

Yes. Pneumàtic is the normal Catalan word for tire.

Be careful not to confuse it with related words:

• roda = wheel
• pneumàtic = tire

So the rubber outer part is the pneumàtic, while the whole wheel assembly may be referred to differently depending on context.

Yes. Quina mena de pneumàtic és aquest? is also correct and means almost the same thing.

• tipus de = type of
• mena de = kind of / sort of

Both are natural, though tipus may sound a bit more technical or classificatory.

Notice the agreement change:

• tipus is masculine → quin tipus
• mena is feminine → quina mena

Normally, no. Standard Catalan uses quin tipus, not què tipus, in this structure.

Use:

• quin tipus de... = what type of...
• quina mena de... = what kind of...

Què is used for what? in other kinds of questions, but not usually before a noun in this pattern.

No. Standard Catalan normally uses only the final question mark:

• Quin tipus de pneumàtic és aquest?

Unlike Spanish, Catalan does not normally use an opening question mark ¿.

The given word order is the most natural one:

• Quin tipus de pneumàtic és aquest?

Catalan can sometimes vary word order for emphasis, but this is the standard, neutral way to ask the question.

For a learner, this is the pattern to remember:

• Quin/Quina + noun + és + aquest/això/allò?

So it is best to learn this sentence exactly as it stands.