I have a section of the wood pegboard on which I hang several standard type hammers, and on one long peg I have about six 12 to 14" adjustable wrenches and have not had a problem.

I would imagine if the I started hanging my 5lb sledges on it I would have problems but these pegs have been on that board for over 20 years.

I did discover there are two sizes of pegs and pegboards. I have some of the smaller pegboard for little things like parts in the store hanging packaging but for the tools I have the larger pegs.

One is like 3/16" and the other is 1/4" to 5/16" It is noticeable and the pegs do not interchange.