Originally Posted by
merziac
Those stems are well known for the internal wedge cracking and breaking all on their own for poor design, overtightening, lack of proper lube, etc.
These won't tolerate a much bigger bar and I don't think that would break the wedge, seems to me like it might help with keeping the wedge intact.
Too small would more likely be the culprit I think.
Could be they could no longer find the appropriate wedge.