Felgen er gammel.

It marks the noun as definite singular: felgen = the rim.

In Norwegian, the definite article is often attached to the end of the noun instead of being a separate word.

• en felg = a rim
• felgen = the rim

So this sentence uses a definite noun: the rim.

Because Norwegian usually expresses definiteness by adding an ending to the noun.

With this noun:

• en felg = a rim
• felgen = the rim

That is a very common pattern in Norwegian. English uses a separate article (the), but Norwegian often uses a suffix instead.

A useful extra note:

• If you add an adjective before the noun, Norwegian often uses double definiteness:
  • den gamle felgen = the old rim

So in the original sentence, felgen already contains the idea of the.

Er is the present tense of the verb å være (to be).

So:

• er = is / am / are depending on the subject in English

In Norwegian, the present tense form does not change for different persons:

• jeg er = I am
• du er = you are
• han/hun er = he/she is
• vi er = we are

So Felgen er gammel uses the normal present-tense verb er.

Because adjectives in Norwegian agree with the noun in gender and number, even when they come after er.

Here, felgen is singular and treated as a common gender noun, so the adjective form is:

• gammel for singular common gender

Compare:

• en gammel felg = an old rim
• felgen er gammel = the rim is old

Other forms are:

• gammelt for singular neuter
  • et gammelt hus = an old house
• gamle for plural
  • gamle felger = old rims
  • felgene er gamle = the rims are old

So gammel is the correct agreement form here.

This is because gammel is being used predicatively — that means it comes after the verb er, not directly before the noun.

In Norwegian, predicate adjectives usually agree in gender and number, but not in the same way as adjectives placed directly before a definite noun.

Compare:

• Felgen er gammel = predicate adjective
• den gamle felgen = adjective directly before a definite noun

So:

• after er: gammel
• before a definite noun: gamle

That difference is very important in Norwegian.

The dictionary form is felg.

You will normally learn it with an indefinite article:

• en felg = a rim

Then the definite singular becomes:

• felgen = the rim

So the pattern is:

• felg = base noun
• en felg = indefinite singular
• felgen = definite singular

In Bokmål, nouns like this are often treated as common gender in beginner explanations, which is why you see:

• en felg
• felgen

Depending on dictionary and usage, some nouns may also be treated as feminine by some speakers, but en felg / felgen is completely normal and safe to learn.

For a learner, the important thing in this sentence is:

• the noun is being used in a form that takes gammel, not gammelt

You switch the order of the verb and the subject:

• Felgen er gammel. = statement
• Er felgen gammel? = Is the rim old?

This is a very common Norwegian pattern:

• statement: subject + verb
• yes/no question: verb + subject

Add ikke after the verb:

• Felgen er ikke gammel. = The rim is not old.

That is the normal placement in a simple sentence:

• subject + verb + ikke + adjective

A careful approximate pronunciation is:

• Felgen ≈ FEL-gen
• er ≈ short air / ehr
• gammel ≈ GAM-mel

A rough full approximation:

• FEL-gen er GAM-mel

A few notes:

• The g in felgen is pronounced.
• The mm in gammel sounds like a long/doubled m.
• Norwegian pronunciation varies somewhat by dialect, but this approximation is good for standard Bokmål-oriented learning.