MVC router class

Below is what I have come up with for a router/dispatcher system for my personal framework I am working on. Can you please review and tell me any improvements that could be made?

The first part is an array of URI -> to class/method/id_number/page_number using regex. I have only included a partial list of routes, there will be at least 50 possible routes that will have to run the regex on. I am thinking that is pretty bad for performance, but it seems the best way I know of to do it, since I need to match page numbers and id numbers when they exists.

I am new to MVC so this is my first attempt and I am sure you guys can give me improvement on this, thanks for any tips or help!

.htaccess file:

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$   index.php?uri=$1    [NC,L,QSA]

Map array():

/**
 * Map URI to class/method and ID and Page numbers
 * Must be an array
 */
$uri_route_map = array( 
    //forums
    'forums/' => array(
        'controller' => 'forums',
        'method' => 'index',
        'id_number' => '',
        'page_number' => ''),

    'forums/viewforum/(?\d+)' =>  array(
        'controller' => 'forums',
        'method' => 'viewforum',
        'id_number' => isset($id_number),
        'page_number' => ''),  

    'forums/viewthread/(?\d+)' =>  array(
        'controller' => 'forums',
        'method' => 'viewthread',
        'id_number' => isset($id_number),
        'page_number' => ''),

    'forums/viewthread/(?\d+)/page-(?\d+)' =>  array(
        'controller' => 'forums',
        'method' => 'viewthread',
        'id_number' => isset($id_number),
        'page_number' => isset($page_number)),

    // user routes
    // account routes
    // blog routes 
    // mail routes
    // various other routes
);

Router class that reads and matches the Map array above

```
/**
* Run URI against our Map array to get class/method/id-page numbers
*/
class Router
{
private

If you can limit your URI structure to using a delimiter - / comes to mind - you could avoid the regex.

Here's a rough example (not with any configuration, but shows the concept):

$uri = 'forums/viewforum/1';
$parts = explode('/', $uri);

$controller = $parts[0];
$method = $parts[1];
$id = parts[2];

I'd take a look at the router implementations of some popular frameworks (my recommendation would be ZF's router, but that's just me) - there's nothing wrong from learning how someone else tackled the same problem.

StackExchange Code Review Q#4031, answer score: 7