Das Schutzblech ist über dem Reifen.

Schutzblech is a neuter noun in German, so its nominative singular article is das.

In this sentence, das Schutzblech is the subject, so it stays in the nominative:

• das Schutzblech

A good thing to remember is that every German noun has a grammatical gender:

• der = masculine
• die = feminine
• das = neuter

So you have to learn Schutzblech as das Schutzblech, not just the bare noun.

It is dem Reifen because the preposition über is being used here with the dative case.

German prepositions like über can take:

• accusative when there is movement toward a destination
• dative when describing a fixed location

Here, the sentence describes location: the fender is above the tire. Nothing is moving from one place to another. So German uses the dative:

• über dem Reifen = above the tire

Since Reifen is masculine (der Reifen), its dative singular form is:

• dem Reifen

Über is a two-way preposition (Wechselpräposition). That means it can take either accusative or dative, depending on meaning.

Use:

• dative for location: where something is
• accusative for direction/movement: where something is going

In your sentence:

• Das Schutzblech ist über dem Reifen. This tells us where the fender is located, so we use dative.

Compare:

• Das Schutzblech ist über dem Reifen. = The fender is above the tire.
• Ich halte das Schutzblech über den Reifen. = I hold the fender over the tire.

The second example suggests placement or position relative to something in a more directional sense, so accusative can appear there.

Schutzblech is a compound noun, which is very common in German.

It is made of:

• Schutz = protection
• Blech = sheet metal / metal plate

Together, Schutzblech means something like a protective metal cover, often a fender or mudguard depending on context.

In German compounds, the last part determines the grammatical gender. Since das Blech is neuter, the whole word is also neuter:

• das Blech
• das Schutzblech

German main clauses usually follow the verb-second rule.

That means the finite verb comes in position 2:

• Das Schutzblech = position 1
• ist = position 2
• über dem Reifen = the rest of the sentence

So the sentence structure is perfectly normal:

• Das Schutzblech ist über dem Reifen.

You could also move another element to the front, but the verb would still stay second:

• Über dem Reifen ist das Schutzblech.

That is less neutral in many contexts, but grammatically correct.

In German, all nouns are capitalized.

So in this sentence:

• Schutzblech is capitalized because it is a noun
• Reifen is capitalized because it is a noun

Other words are not capitalized unless they begin the sentence:

• Das is capitalized here because it starts the sentence
• ist
• über
• dem

This is one of the most noticeable differences from English spelling.

Not always. Über often corresponds to over or above, but the best English translation depends on context.

It can mean things like:

• spatially above: über dem Tisch = above / over the table
• about/concerning: über Musik = about music
• across: über die Straße = across the street

In your sentence, the spatial meaning is intended, so above or over works.

Yes, that is possible.

• über dem Reifen = above the tire
• oberhalb des Reifens = above the tire / higher than the tire

But the grammar changes:

• über takes dative here: dem Reifen
• oberhalb is usually followed by the genitive: des Reifens

So both can express a similar idea, but über dem Reifen is often simpler and more common for learners.

It is in the nominative case because it is the subject of the sentence.

Ask yourself: what is above the tire?

Answer: das Schutzblech

So:

• subject = das Schutzblech
• verb = ist
• prepositional phrase = über dem Reifen

That is why das Schutzblech stays in the nominative.

The plural of Schutzblech is usually Schutzbleche, and the plural of Reifen is Reifen.

So:

• singular: Das Schutzblech ist über dem Reifen.
• plural: Die Schutzbleche sind über den Reifen.

Notice the changes:

• das → die for plural nominative
• ist → sind
• dem Reifen → den Reifen

In the dative plural, German usually adds -n to the noun if possible, but Reifen already ends in -n, so it stays Reifen.

Reifen is pronounced roughly like RY-fen in English approximation, with:

• ei pronounced like the i in my
• the first syllable stressed: REI-fen

It is the normal German word for a tire.

Be careful not to confuse it with the verb reifen, which means to ripen. In writing, context usually makes the meaning clear:

• der Reifen = the tire
• reifen = to ripen