I've bought a LOT of kit from AliExpress, so let me share my experiences:
- Summer gear: Check the size chart, which usually matches Euro race sizing (if it doesn't, order the appropriate size). Use chest size, not height or weight (works for my body type - YMMV). I have a lot of Nalini clothing, take a size 3 jersey and size 4 bibs, and find a Chinese size M jersey and size L bibs works well. The bibs inevitably aren't as comfortable as Nalini, but size XL leaves too much excess room for my junk (or maybe my junk is too small - ha, ha), but size M is too tight in the waist and legs (whereas Nalini size 3 or 5 bibs are fine if I can't get a 4). One size 'wrong' on a China-made jersey is similar to being one size 'wrong' on a Euro-made jersey.
- Gloves: go up one size. I take a size 3 Nalini glove, but order size L Chinese gloves, and even those are pretty tight (never tried an XL - afraid I'd get something too loose, which I HATE in a glove).
- Socks: My foot size is (USA) 10.5. China-made socks are frequently offered as 'one size fits all'. These aren't useless, but they are noticeably small. So, if sizes are available, I order the biggest Chinese sock I can.
- Fall/Winter gear:
--- First, fleeced vests: like summer jerseys, check the size chart which will likely match Euro race fit. I have China-made size M vests that fit perfectly. One manufacturer (I checked the size chart and ordered accordingly) sent me size S, which was perfect.
--- Fleeced Bib Tights: go up, WAY up, in size. I order 2XL or 3XL. For whatever reason, these are sized ridiculously small - in the waist, around the legs, and in length. In any event, NOWHERE NEAR as comfortable as Euro-made tights. It's been a long time since I ordered China-made tights - I spend the extra money for the 'real thing' due to comfort issues.
--- Fleeced jacket: never ordered one, so no comment
--- Non-fleeced jacket: I've ordered only one of these (according to the size chart), so not a large sample size, but while it fit well in the body, the arms were RIDICULOUSLY loose.