How to transition with transition tracks with Traktor S2
Hello,
I’m having a hard time to transition tracks that are transitional tracks (I.E 70-128) on my Traktor s2. I know obviously I cannot sync the up coming track with the transitional track. And, I’ve tried to beat matching, I did the arithmetic in my head trying to find any possibility to make it work. And, still no good at all. I need help! 
First of all disable Sync, Snap and Quantize. Welcome to the real world.
Set your Load marker to the start of the first beat. It’s going to be 70bpm from here for you to mix out of your previous track that you should manually get to be 70bpm as well while it’s playing.
Now go to where the first beat is 128bpm … And tag this as your grid marker, then set the track BPM at 128.
You will need to manually mix this in time, not too hard when your BPM is 70bpm, and you’re mixing out of a track that’s at 70bpm. Luckily you’ll have your trusty grid there to mix out of your transition track because you know, it’s hard work mixing manually twice in a row 
Good luck.