No, there are no relation events in Eloquent. But you can easily do it yourself (Given for example Ticket belongsToMany Component relation):

// Ticket model

use App\Events\Relations\Attached;

use App\Events\Relations\Detached;

use App\Events\Relations\Syncing;

// ...

public function syncComponents($ids, $detaching = true)

{

    static::$dispatcher->fire(new Syncing($this, $ids, $detaching));

    $result = $this->components()->sync($ids, $detaching);

    if ($detached = $result['detached'])

    {

        static::$dispatcher->fire(new Detached($this, $detached));

    }

    if ($attached = $result['attached'])

    {

        static::$dispatcher->fire(new Attached($this, $attached));

    }

}

event object as simple as this:

<?php namespace App\Events\Relations;

use Illuminate\Database\Eloquent\Model;

class Attached {

    protected $parent;

    protected $related;

    public function __construct(Model $parent, array $related)

    {

        $this->parent    = $parent;

        $this->related   = $related;

    }

    public function getParent()

    {

        return $this->parent;

    }

    public function getRelated()

    {

        return $this->related;

    }

}

then a basic listener as a sensible example:

    // eg. AppServiceProvider::boot()

    $this->app['events']->listen('App\Events\Relations\Detached', function ($event) {

        echo PHP_EOL.'detached: '.join(',',$event->getRelated());

    });

    $this->app['events']->listen('App\Events\Relations\Attached', function ($event) {

        echo PHP_EOL.'attached: '.join(',',$event->getRelated());

    });

and usage:

$ php artisan tinker

>>> $t = Ticket::find(1);

=> <App\Models\Ticket>

>>> $t->syncComponents([1,3]);

detached: 4

attached: 1,3

=> null

Of course you could do it without creating Event objects, but this way is more convenient, flexible and simply better.