No set rule , the Lasertecson my R75/7 go the opposite way to the Distanzas on the G/S.
Both work very well.
What size rear Distanza are you ruunning - I ordered a 4" for my G/S and they sent a 110/80 instead, which actually is 110 on the rim.
Just wondered if a 120 fits and works any better than a 110.
Adelaide Hills, Australia. 93 R100 GS, 77 R75/7 ,70 BSA B44VS, , 86 R80 G/S PD, 95 BMW Funduro F650 ST