Learn Hardcore Russian: На шоссе я никогда не катаюсь на самокате, даже если на мне шлем. - On the highway I never ride a scooter, even if I am wearing a helmet.

На шоссе я никогда не катаюсь...
Literally: On the highway I never ride...
This puts emphasis on the place: "As for the highway, I never ride a scooter there."
Я никогда не катаюсь на шоссе...
More neutral; emphasizes the subject and the habitual action rather than the location.

Both versions are grammatically correct. The original just foregrounds the location for contrast (for example, maybe the speaker does ride a scooter elsewhere, just not on the highway).

Why is шоссе the same form after на? Shouldn’t it change case?

Шоссе is an indeclinable noun in Russian, usually neuter. That means it keeps the same form in all cases:

nominative: это шоссе
prepositional (after на with a static location): на шоссе
accusative: видеть шоссе, etc.

Here на шоссе uses the prepositional case for a location (on the highway), but you do not see any change in the word because шоссе does not decline.

Why is the preposition на used with шоссе and самокате, not в?

In Russian, на and в are partly about physical logic (surface vs. inside), and partly just fixed patterns.

На шоссе
- A road or highway is seen as a flat surface, so you are on it.
- So Russian uses на for surfaces: на улице (on the street), на дороге (on the road), на шоссе (on the highway).
На самокате
- With vehicles, Russian often uses на with the prepositional case:
  - ездить на велосипеде – to ride a bicycle
  - ездить на лошади – to ride a horse
  - ездить на самокате – to ride a scooter
- В is used when you are inside something: в машине (in the car), в автобусе (on/in the bus).

So:

на шоссе – on the highway (surface)
на самокате – on a scooter (vehicle you are on, not inside)

Could you also say по шоссе я катаюсь на самокате? What is the difference between на шоссе and по шоссе?

You can say по шоссе я катаюсь на самокате, but the nuance changes:

на шоссе focuses on location: on the highway (there), I don’t ride a scooter.
по шоссе focuses on movement along or along the length of the highway.

So:

Я катаюсь на самокате на шоссе – I ride a scooter on the highway (that is the place).
Я катаюсь на самокате по шоссе – I ride a scooter along the highway (moving along it).

In this sentence, the idea is more “I never ride there, on the highway,” so на шоссе fits better.

What exactly does катаюсь mean? How is it different from езжу or еду?

Катаюсь is the 1st person singular of кататься, a reflexive verb.

кататься roughly means “to ride / roll / go around (for fun or casually),” often with no specific destination, or as a leisure activity:
- кататься на самокате – ride a scooter (usually for fun)
- кататься на велосипеде – ride a bike (recreational)
- кататься на коньках – go ice skating
- кататься на лыжах – go skiing
ездить / ехать are general motion verbs:
- ехать – to go (by vehicle) in one direction, right now.
- ездить – to go (by vehicle) habitually or in multiple directions.

Using кататься here suggests something casual or recreational, not just any functional trip.

So:

Я никогда не катаюсь на самокате на шоссе – I never ride a scooter on the highway (implies the act itself, often recreational).
Я никогда не езжу на самокате по шоссе – I never travel by scooter along the highway (more like a transport choice).

Why is катаюсь reflexive (-сь) here? What does the reflexive ending add?

The reflexive ending -сь (or -ся) comes from the particle ся, historically meaning “oneself.” With кататься, this form has become lexicalized.

Non-reflexive катать = to roll something, to push something on wheels:
- катать мяч – to roll a ball
- катать коляску – to push a stroller
Reflexive кататься = to roll oneself, to ride; the subject is moving on something:
- кататься на самокате – to ride a scooter
- кататься на велосипеде – to ride a bicycle

So катаюсь is reflexive because the action is “rolling myself around,” not rolling some other object.

Why do we need both никогда and не? Isn’t that a double negative?

In Russian, negative words like никогда, ничего, никто require не with the verb. This is not considered a mistake; it is the normal grammar.

Я никогда не катаюсь... – literally: I never not-ride...
But in Russian, this is simply how you say I never ride....

If you said:

Я никогда катаюсь... – this is ungrammatical; никогда must be supported by не with the verb.

So:

English: one negative per clause: I never ride a scooter.
Russian: никогда
- не: я никогда не катаюсь на самокате.

Why is самокате in that form? What case is it, and what is the pattern?

Самокате is the prepositional singular of самокат (scooter).

Declension of самокат (masculine, hard-stem noun):

nominative: самокат
genitive: самоката
dative: самокату
accusative: самокат
instrumental: самокатом
prepositional: самокате

The verb кататься with a vehicle uses на + prepositional:

кататься на самокате
кататься на велосипеде
кататься на лошади

So на самокате is prepositional case governed by на in this particular usage.

Could we omit на and just say я катаюсь самокате?

No. The preposition на is required here.

The pattern is:

кататься на чём? – to ride on what?

So you must say:

кататься на самокате
кататься на велосипеде
кататься на коньках

Without на, самокате would have no grammatical connection to the verb and the phrase would be incorrect.

What does даже если add to the meaning? How is it different from just если or from хотя?

если = if (neutral conditional).
даже если = even if, adds emphasis and contrast: the condition does not change the outcome.
хотя = although / though, implies that the condition is real or very likely, not hypothetical.

In the sentence:

...даже если на мне шлем – even if I’m wearing a helmet
The meaning is: “It doesn’t matter whether I have a helmet or not; I still never ride on the highway.”

If you said:

...хотя на мне шлем – although I’m wearing a helmet
That sounds more like: “In fact I do have a helmet, yet I don’t ride on the highway.”
Here the nuance is weaker and a bit off for the idea of a general rule; даже если is much more natural.

In даже если на мне шлем, where is the verb? Why is there no есть?

Russian often drops the verb быть (to be) in the present tense in statements of existence or identity.

Full, very explicit version: даже если на мне есть шлем
Natural colloquial version: даже если на мне шлем

Both are grammatical; the second is more common in everyday speech.

Literally:

на мне (есть) шлем – on me (there is) a helmet
English expresses this as “if I’m wearing a helmet,” but Russian treats it as a static situation: “if a helmet is on me.”

What exactly does на мне шлем mean, and how is it different from я в шлеме?

Both can be used, but there are nuances:

На мне шлем
- Literally: On me (there is) a helmet.
- Structure: на
  - prepositional pronoun (мне) + subject (шлем).
- Feels a bit more physical/visual: a helmet is located on my body.
Я в шлеме
- Literally: I am in a helmet.
- Structure: subject (я) + в
  - prepositional noun (шлеме).
- Describes your state or outfit: “I’m wearing a helmet / I’m in a helmet.”

In this sentence, даже если на мне шлем is very natural and matches the idea of “even if there is a helmet on me,” i.e., even if I have this protective item on.

Why is the verb in the present tense катаюсь, even though we are talking about a general rule?

Russian uses the simple present tense for:

actions happening now
habitual actions
general rules or truths

So я никогда не катаюсь на самокате на шоссе means:

I never ride a scooter on the highway (as a standing rule, habit).

This is the same as English simple present in a general/habitual sense:

I never ride a scooter on the highway.

There is no need for any special tense; the simple present covers it.