If you are entering Thailand on an international flight with a lot of baggage, and you have to make a connecting domestic flight inside Thailand, you will find a huge difference in the domestic baggage weight limits (much less!).
You need to make sure you understand the domestic baggage limits and charges, if you want to carry your international baggage limit on a domestic flight while in Thailand.
Contact the domestic airlines and make 100% sure you understand their baggage weight limits and the charges if you go over that limit.