First of all, I wonder about this line: LCDOUT $FE,$8D, DEC speed, "km/h "
--- > $8D ??? I think you meant $80 (beginning of first line)

Then, if it's the case you can use:

If speed < 100 then X= 1
If speed < 10 then X = 2
LCDOUT $FE,$8D + X, DEC speed, "km/h"


Cleaver!