Minor speed on boots doesn't affect Mounted speed.
The only way to get more then Minor speed on boots (8%) while on your turtle, is to get the Guild Perks +10%. You can get a max of 16% improvment, by having the actual Guild Perks + 4% on boots and +2% on gloves.
for the fact to make it sound like "spectral tiger" or w/e, if you cliked the thread hoping for a new mount for sub lvl 20s, than something is wrong with the way your head works