A bit of background might dispel the confusion: Ryanair, like other low-cost European airlines, does not include any hold (check-in) luggage allowance in its regular fares. Many people therefore travel with only hand (carry-on) luggage and they are very strict about their numbers (no personal item, even a large woman's handbag must fit in your main carry-on or you will incur additional fees to gate-check some of your luggage) and dimensions (it has to fit in a metal box at the airport, total dimension is not relevant). That's why they emphasise this so much.
The restrictions on hold luggage are mostly weight-based and going over 20kg is very expensive. With all these restrictions, dimensions are not usually a big problem and Ryanair does not rely on that to restrict what you may check in. Obviously, even if they are not communicating it prominently, very unusual luggage would be difficult to handle and there is a limit. I did find a reference to the size of hold luggage in a FAQ:
For health and safety reasons Ryanair does not accept for carriage any individual item exceeding 32 kilos or with combined dimensions of more than 81cms (height), 119cms (width) and 119cms (depth). This weight limit does not apply to mobility equipment.
Again, the total of the three dimensions isn't relevant but I assume your 162cm luggage should fit easily within this 81x119x119cm box. There is also some confusing language in the General terms & conditions suggesting that sporting equipment like skis or fishing rods might also be allowed (skis would typically be longer than 119cm so it would make little sense to mention them explicitly if they were only allowed provided they fit in these dimensions).