واقي الطين فوق محور العجلة وأسلاك العجلة.

Because Arabic often leaves out the present-tense to be.

So واقي الطين فوق محور العجلة وأسلاك العجلة literally works like:

• واقي الطين = the mudguard
• فوق محور العجلة وأسلاك العجلة = above the wheel axle and the wheel spokes

In natural English, you add is, but in Arabic the sentence is complete without it.

If you wanted past or future, Arabic would usually use a verb such as كان or سيكون.

It is an iḍāfa construction, often called a construct phrase.

Structure:

• واقي = protector / guard
• الطين = mud

So literally it is protector of the mud or, more naturally, mudguard / fender.

This pattern is very common in Arabic:

• محور العجلة = axle of the wheel
• أسلاك العجلة = spokes/wires of the wheel

So the sentence contains several iḍāfa phrases.

Good question. This happens because واقي is the first word of an iḍāfa.

Two important points:

1. The first noun in an iḍāfa usually does not take الـ

   • So you say واقي الطين
   • Not normally الواقي الطين

2. واقٍ is the indefinite form when the word stands by itself

   • واقٍ = a protector/guard
   • But in iḍāfa, the form appears as واقي
   • So: واقي الطين

So واقي الطين is the correct construct form.

In an iḍāfa, the definiteness of the whole phrase depends on the second noun.

Since الطين is definite, the whole phrase واقي الطين is also definite.

The same applies to:

• محور العجلة = the wheel axle
• أسلاك العجلة = the wheel spokes

So even though محور and أسلاك do not have الـ, the whole phrases are definite because العجلة is definite.

فوق means above or over.

In learner-friendly terms, you can think of it as working much like a preposition:

• فوق محور العجلة = above the wheel axle

More precisely, in traditional grammar فوق is a noun of place / ظرف used adverbially, but for understanding this sentence, treating it like above is perfectly fine.

So the basic structure is:

• واقي الطين = subject/topic
• فوق محور العجلة وأسلاك العجلة = where it is

Because both are iḍāfa phrases:

• محور العجلة = axle of the wheel
• أسلاك العجلة = wires/spokes of the wheel

Arabic often expresses possession or part-whole relationships this way.

English may prefer:

• the wheel axle
• the wheel spokes

But Arabic naturally uses:

• noun + noun
• literally axle of the wheel, spokes of the wheel

Yes, أسلاك is the plural of سِلْك, meaning wire.

But in bicycle vocabulary, the spokes are literally wire-like parts, so أسلاك العجلة can refer to the spokes of the wheel.

So depending on context, it may be understood as:

• wheel wires literally
• wheel spokes more naturally

This is a good example of vocabulary becoming more specialized in context.

Yes.

The و simply joins the two nouns/phrases:

• محور العجلة
• أسلاك العجلة

So the meaning is:

• above the wheel axle and the wheel spokes

Arabic often states the preposition or spatial word only once, and it automatically extends over the coordinated phrase.

A careful reading is roughly:

wāqī aṭ-ṭīn fawqa miḥwar al-ʿajala wa-aslāk al-ʿajala

A few pronunciation notes:

• الطين is pronounced aṭ-ṭīn, because ط is a sun letter, so the l of الـ assimilates.
• العجلة keeps the l sound: al-ʿajala
• وأسلاك is pronounced wa-aslāk
• ع in العجلة is the Arabic letter ʿayn, which has no exact English equivalent.
• ط is an emphatic t sound.

If you want the fully vocalized form, it is:

وَاقِي الطِّينِ فَوْقَ مِحْوَرِ العَجَلَةِ وَأَسْلَاكِ العَجَلَةِ

Arabic often repeats the noun in technical descriptions, labels, and formal explanations for clarity.

So:

• محور العجلة وأسلاك العجلة

can be clearer in a diagram or textbook than something shorter like:

• محورها وأسلاكها = its axle and its spokes

Both are possible, but repeating العجلة avoids ambiguity and sounds very natural in descriptive or instructional Arabic.