I've found a nice suspension but its steer tube has a length of 17.5 cm and my bike's frame is rated for a minimum of 18 cm. Is it possible to (somehow) extend its length? Is it a common practice and would be safe to weld a steel extention to it?
FWIW. It is probably possible to find someone who can weld an extension onto a steel steerer, but unless it is a really sweet deal then you are probably better off looking for another fork ...
AND/OR, sourcing a replacement "shoulder/steerer" assembly for the particular suspension fork.