Learn Swedish: Du borde använda sadeln, eftersom du drar i tygeln hårdare än han. - You should use the saddle, since you pull the rein harder than he.

In Swedish, än (than) is traditionally treated as a conjunction that connects two clauses. The full implied thought is ...hårdare än han (drar) (...harder than he pulls). Because "he" is the subject of that implied verb, we use the subject pronoun han. While you might hear honom in very casual spoken Swedish, han is the grammatically correct choice here and is expected in writing.

Why is the preposition i used in drar i tygeln?

When you physically pull on, tug, or grab hold of an object, Swedish commonly pairs the verb drar with the preposition i. If you just said du drar tygeln without the i, it would sound more like you are dragging the rein across the ground or hauling it from one place to another, rather than tugging on it while riding.

Why use borde instead of bör for "should" in this context?

Borde is technically the past tense form of bör, but it is standardly used to give polite advice or recommendations in the present tense (just like "should" or "ought to" in English). Using bör would sound much stronger and more formal, expressing a strict rule or strong obligation.

If I wanted to make the second part negative ("since you do not pull"), where would inte go?