im importing a large csv programmatically and i want to save product length width height and didn't found any post related to this, so:

I tried to:
$product->setCustomAttribute('width',(int)$data[22]);
$product->setCustomAttribute('ts_dimensions_width',(int)$data[22]); #from product attributes
$product->setData('lenght',$data[21]);

Any of these more "logical" ways didn't work.
any ideas?
thanks!