The range is 60ft so it does give some wiggle room for distance. As another point Jørmund won't be casting it now, he's just making sure whoever is going to want the boost has the ring already for when he needs to cast it.

Edit 1:
Eventually he will try to procure the material to make two more sets just so he can use it without needed to remember who has a ring and who does not.

Edit 2:

For better detail, warding bond grants the recipient +1 to AC and all saving throws. They are also resistant to all damage. The spell lasts for an hour, until Jørmund drops to 0 hp, or the recipient is more than 60ft away from Jørmund.

Down side is that any damage the recipient takes, Jørmund takes.