No, you do need to specify the type.

The routes compiler has no way of knowing what the type of the method is, it doesn't try to find out, it just generates scala code based on the routes file and the routes file only.  The way it, in the reverse router and forward router, gets the path bindable, is it generates some code saying:

```scala
implicitly[PathBindable[Asset]]
```

If you don't put a type in the routes file, it assumes `String`, and so generates:

```scala
implicitly[PathBindable[String]]
```

So the only way to get a custom path bindable to work (because we can't change the `String` path bindable because it's used for strings in every route, not just assets route), is to have a non String type explicitly declared in the routes file.