Rammus Runes explained
There's one set of runes for Rammus on patch
11.8
that is the clear favorite for LoL players and pros alike. The best Rammus Runes on the position 
Jungle are Resolve as the primary path and
Precision as the secondary path with a pick rate of 53%. Besides runes you should take a look on Rammus Build and if you are interested in pro matches take a look at Rammus Probuilds. If you want to discuss
Rammus then you should visit the champion subreddit.
Primary path on Rammus
Resolve empowers the survivability of Rammus and increases the tankiness. Most of high elo players – and our LoL pros in the the major regions – have agreed that
Aftershock is the best keystone rune to run on
Rammus. This keystone rune bulks you up, increasing both armour and magic resistance, once you immobilized a champion.
Aftershock synergises both with the sheer amount of crowd control Rammus possesses and the need to be tanky as soon as you engage. This is usually followed up by taking
Font of Life,
Conditioning and
Unflinching.
Font of Life provides your teammates with more sustain by healing them whenever they attack a champion whose movement you've recently impaired.
Conditioning powers up Rammus tankiness after the laning phase.
Unflinching inceases Rammus tenacity based on your missing health.
Secondary path on Rammus
When it comes to your secondary path, most
Rammus players prefer to go with
Precision.
Precision improves attack and sustained damage on Rammus troughout the match. On the
Precision path, the best runes for Rammus are
Triumph and
Legend: Tenacity.
Triumph restores on Rammus a part of missing health and award bonus gold, if a champion is killed. Rammus gains extra Tenacity with every additional stage of
Legend: Tenacity.