BJJ uses a mixture of Judo and Wrestling style takedowns. It is very common to see leg grab takedowns in BJJ, which are common in Wrestling and now banned in Judo. Setting up leg grabs with the Gi is a much more difficult task than without the Gi because your opponent can keep you at distance with grips.
Multiple Australian and Oceania Champion and a 2008 Beijing Judo Olympian Matt D’Aquino gives some excellent advice in the following article and video.
He has been studying Judo for over 23 years. He is a 3rd Degree Black belt and a purple belt in BJJ. Matt is also known worldwide for his excellent website Beyondgrappling.com . Matt has also come out with a great new DVD set for BJJ players: Judo for BJJ.
When you want to set up a takedown, it all comes down to tricking your opponent into going the direction you want them to go.
Many judoka and BJJ players go for 1 off attacks and these rarely work (unless you are bigger or stronger than you opponent). But more often than not if your opponent sees a one off attack coming, they will counter you or avoid your throw completely.
Combinations and setups are everything!!!
When I am teaching at the club I always say that we need to be like a a boxer- we need to throw combinations in order to finish our opponent and get a winning score.
We need to fake forwards if we want to throw backwards and fake backwards if we want to throw forwards.
This means that you need to find and sequence takedowns together.
Start sequencing your takedowns. Start faking in the opposite direction BEFORE you attack and I guarantee you will take more people down and you will finally enjoy the ‘chess match’ of BJJ more than you ever have before.
In this video from Judo for BJJ, you will see how you can use this principle to set up leg grabs in BJJ: