190/50 v190/55

[Billy the kid]

a taller tyre raises the axle higher off the ground so the rear wheels centre of gravity will be higher,hence more inclined to tip in.As the rear wheel also includes the sprocket and rotor and chain,thats a fair bit of mass thats higher off the ground.raising the rear suspension only,only lifts the rear of the bike and rider a bit further up with the heavy spinning wheel still quite low down.I,ll still stick with a higher profile rear as you don,t have to decrease the trail and rake as much for better turn in.

When you say rasing the rear shock what do you mean??Fitting shorter dog bone or any other way?
In the case of shorter dog bones they definately raise the axle of the swing arm shorten the wheel base and make the rake and caster more aggressive.
I cannot remember any other way..
But as you say the cheapest,fastest,easiest way to get fast geometry is a 55 rear and 60 front!Take a few clicks off compression,add rebound and back off on the preload and you 'll see even major turn in abilities on the track!