When I was a size 10 I had terrible chub rub. This has continued, through being a size 18 and now a size 14. For the last year I have been using a combination, I have finally found a solution and can wear dresses without shorts underneath, even when it's really hot.
I believe most of the problem is caused by sweating, not size as often believed. Why else would I have suffered when I was a size 10? I know many much larger people who don't seem to suffer.
I use the Sure cream in the crease at the tops of my legs, which calms the sweating and the Body Glide on my thighs, which stops the rubbing. You can still feel the slight rub, which takes some getting used to after over 30 years of suffering, but no soreness.
Body Glide is available from Amazon.
Would be interested to hear if this works for others. This has been my best summer ever.