Table rate shipping set max limit for the weight

In case of table rate shipping you can set the max limit for the weight by applying this process:

1. in shipping/etc/system.xml for tablerate fields insert these lines

Weight Max Limit text 81 1 1 1

2. you can set the default value in shipping/etc/config.xml for tablerate

700

3. in shipping/model/carrier/tablerate.php put these lines after line 113

 

$maxWeight = $this->getConfigData('max_limit'); 
if($oldWeight > $maxWeight){ 
    $error = Mage::getModel('shipping/rate_result_error'); 
    $error->setCarrier($this->_code); 
    $error->setCarrierTitle($this->getConfigData('title')); 
    $errorMsg = $this->getConfigData('specificerrmsg'); 
    $error->setErrorMessage($errorMsg?$errorMsg:Mage::helper('shipping')->__('Your order is not eligible for this shipping method. Please choose another method.')); 
    return $error;
} 

now if you have max weight in cart the message will be display on checkout shipping method process.

this may help you!