I got a new gt-31. It is the blue tooth model called BGT31. It does not keep the newest max speed and 10s in its memory.  Anytime I switch from speed mode it resets the speed values. Everytime i switch mode back to speed...the speed values are zero. It does record my data on the chip ok. I can't look at my top speed after I go sailing until I download my data onto the computer. My old GT31 didn't do this. Can anyone help? I already sent it back once and got a new one.
Dan Sullivan 
Hi Dan, this might be a firmware issue or your speed genie settings. Compare your settings and firmware version to those on your other GT-31.
Hi I have the same problem too , the diference is that some times the speeds are recording and some others are not , without make any changes in the gps menus and settings.The model is the GT-31.Can anyone help???
Sounds like the speed genie is set too high. Please check it under settings what speed it is set.