Gladly, you’re welcome 
Just tried to mount a Schwalbe Marathon 16 x 1,75 on LT wheel - same problem 
Guess you mean to change the wheels as a whole?
LT wheels are one piece molded…
Like several other Striders I was interested to try wide tyres (and solve corresponding folding problems),
but I’ve switched soon to home brewn wheels…
…therefore, I’m sorry, I can not ensure which size of tyre might work with original (24 spoked) 16 inch Strida wheels.
But I can assure that the tyres Schwalbe City Jet 16 x 1,95, Schwalbe Big Apple 16 x 2,0 and the Schwalbe Marathon 16 x 1,75 (below left) actually fit to the used Alex Y 303 rims.
Alexrims / BMX page2
There’s already information about wheelbuilding at the forum, please take some time to read it…
…and let me know what you’re missing