Why is the title written differently in kana and romaji? Watching the anime titled Ao Haru Ride (AniDB link), I noticed that the title screen displays the title in kana but it is given as アオハライド or Ao Ha Raido, Ao Ha Ride; entirely missing a kana ル for ru

I noticed that this is already present in what seems to be the Japanese manga cover I found on Google images:



The title in kana reads Ao Ha Raido while the title in romaji reads Ao Haru Ride. Why this discrepancy?
From Tae Kim's guide to learning Japanese,


  There is one major driving factor behind the majority of slang in Japanese. The primary goal of most slang is to make things easier to say. In other words, the goal is to reduce or simplify the movement of your mouth. There are two primary ways in which this is accomplished, 1) By making things shorter or, 2) By slurring the sounds together.


This would imply that the author felt that saying 「アオハルライド」is either harder or more annoying (or both) to say in conversation than 「アオハライド」.

You can try it yourself: saying ao haru raido forces you to pause between haru and raido, whereas one can say ao ha raido in one go.

Update 2019:

There's an explanation given in the first volume of the manga. Here's an excerpt from the official translation:


  Right away people sent letters and tweets, asking about the Japanese title Aoharaido. So I'd like to be able to answer.
  
  
    Aoharaido  = youth + ride
  
  
  The Japanese kanji for "youth" can also be read as aoharu, and I imagine that the characters are on a ride through their youth, giving it all they can. Compared to aoharuraido, when you say it out loud, aoharaido is easier to say and more impactful, so that became the title of the series.