The 50 vs 55 is nowhere near an inch difference in height (which is MAJOR). I would caution against lowering just the front that much. Simulating the rear-only tire size change is something like less than 0.2"?
The 55 is a a 10mm rise over a 50 and couple that with how people compare tires.
No one takes a brand new tire off their bike to replace it with a brand new tire so going from a worn tire to a new tire is another 10mm.
This is why people think a 55 is so much better because in reality they are moving to a greater than a 3/4 of an inch rise. If you want to compare tires your supposed to go from a new tire to a new tire.
You are correct. 0.8 of an inch rise is very significant. Most people dont even realize how much of a change that is (worn out 50 to a new 55).
On top of that most people do not bother to setup a bikes ride height correctly.
There is nothing wrong with a 55. It is just a more V shaped profile on a C14 rim which I would prefer on a track but not on the street.
When I got my C14 is I had to hold it down in a turn- It wanted to return to upright. It took new springs and proper sag settings to set up the bike correctly.
If you do not setup the bike for your weight and the weight you are carrying the bike will feel heavy and slow or if you jack up the back or drop the front by an inch it will steer quicker and feel snappy and light.
