Ako jedan kotač izgubi zrak, nećemo voziti dalje nego ćemo zvati pomoć.

Croatian has no articles, so it normally does not use separate words for a/an or the.

So:

• jedan kotač can mean one wheel
• in some contexts it can also feel a bit like a wheel

But unlike English, Croatian usually leaves definiteness to context. You figure out whether it means a wheel, the wheel, or one wheel from the situation.

Ako means if. It introduces a condition:

• Ako jedan kotač izgubi zrak... = If one wheel loses air...

This is a very common pattern in Croatian:

• Ako + clause, main clause

Examples:

• Ako padne kiša, ostat ćemo doma.
• Ako imaš vremena, nazovi me.

So here the first clause sets the condition, and the second clause says what will happen if that condition is met.

This is a very common point for English speakers.

Izgubi is the present form of a perfective verb: izgubiti. In Croatian, after words like ako and kad, a perfective present form often refers to a future completed event.

So:

• ako jedan kotač izgubi zrak literally looks like if one wheel loses air
• but in meaning it is if one wheel loses air / if one wheel should lose air

Croatian usually does not say ako će izgubiti here.

So the structure is natural Croatian:

• Ako + perfective present, then
• future in the main clause

Literally, it means loses air.

In natural English, that would usually be:

• gets flat
• loses air pressure
• goes flat

So kotač izgubi zrak describes a wheel/tyre no longer having enough air inside it.

This is a normal Croatian way to express that idea.

Jedan literally means one.

In this sentence, it most naturally means one:

• Ako jedan kotač izgubi zrak...
• If one wheel loses air...

But because Croatian has no article system, jedan can sometimes also sound like a certain / a in some contexts. Here, though, the basic idea is genuinely one wheel.

Grammar-wise:

• jedan = masculine singular nominative
• kotač = masculine singular nominative

They match because kotač is the subject of izgubi.

Yes, kotač literally means wheel.

A more precise word for tyre/tire is guma. So in everyday speech, many speakers might more naturally say something like:

• Ako jedna guma izgubi zrak...

That said, kotač can sometimes be used more loosely in context, especially when talking about a car wheel as a whole. So the sentence is understandable, but guma would often be more exact if you specifically mean the inflatable tyre.

This is about the future tense.

Croatian future is built with:

• a form of htjeti as an auxiliary
• plus the infinitive

So:

• voziti ćemo / more standard written form vozit ćemo
• zvati ćemo / more standard written form zvat ćemo

But in normal sentence structure, the auxiliary often appears in second position as a clitic:

• ćemo zvati pomoć

In the negative, the auxiliary combines into one word:

• nećemo voziti

So here you get:

• nećemo voziti dalje = we will not drive on
• nego ćemo zvati pomoć = but instead we will call for help

Both parts are future tense; the difference is mainly that the negative future is written as one word: nećemo.

Dalje means further, on, or any farther depending on context.

So:

• voziti dalje = to keep driving / to drive on / to continue driving

In this sentence:

• nećemo voziti dalje means we won’t continue driving

It does not necessarily mean a huge physical distance. It just means we won’t go on any farther.

Here nego means but rather / instead.

The pattern is:

• ne ... nego ...
• not ... but rather ...

So:

• nećemo voziti dalje nego ćemo zvati pomoć
• we won’t drive on; instead, we’ll call for help

This is stronger and more specific than just ali (but). It corrects or replaces the first idea with another one.

Compare:

• Ne pijem kavu nego čaj.
• I’m not drinking coffee but tea.

Pomoć is the direct object of zvati, so it is in the accusative.

However, with this noun, the accusative looks the same as the nominative:

• nominative: pomoć
• accusative: pomoć

That is why you do not see a visible change.

So:

• zvati pomoć = to call help / to call for help

In English we usually say call for help, but Croatian often simply uses zvati pomoć.

Here are the main ones:

• jedan kotač — nominative singular
  because it is the subject of izgubi

• zrak — accusative singular
  because it is the object of izgubi
  For a masculine inanimate noun like zrak, nominative and accusative are the same in form.

• pomoć — accusative singular
  because it is the object of zvati

So the structure is:

• subject: jedan kotač
• verb: izgubi
• object: zrak

and later:

• verb: zvati
• object: pomoć

Because the sentence begins with a subordinate if-clause:

• Ako jedan kotač izgubi zrak, ...

In Croatian, when a dependent clause comes first, it is normally separated from the main clause with a comma.

So the structure is:

• conditional clause: Ako jedan kotač izgubi zrak
• main clause: nećemo voziti dalje nego ćemo zvati pomoć

This is very similar to English:

• If one wheel loses air, we won’t drive on...

Yes. The sentence uses a very natural aspect contrast:

• izgubiti is perfective
• voziti is imperfective
• zvati is imperfective

Why?

• izgubiti zrak refers to a single completed event: the wheel loses air
• voziti describes an ongoing activity: driving
• zvati describes another activity/action: calling

So the sentence presents:

1. one event happens
2. then we choose not to continue one ongoing action
3. and instead perform another action

That aspect choice is very typical and natural in Croatian.