Originally Posted by
andrepinnola
...Hi! I saw your 29" conversion and would like to do the same with my 750 Multi-track. I found Small Block Eight Kenda 29x1.9, (700x48), I think It's gonna be fine and not too tight. Is you frame 17"? Thanks
OP was 3 years ago so he might not answer you. My experience with the Trek 750 is that I think 47 or 48mm will be the max.
I'm curious as to why the OP said this was a conversion -- the bike came stock with 700c wheels, which is the same thing as a 29er. That's like saying New York, New York.