20psi seems VERY low.
Stock Hawk tires as OE set up is 32psi front, 40psi rear.
I would think that on a street tire, minimum PSI would be in the low 30s. Even my Ninja 250 runs 28psi front, 32psi rear.
What does your tube and tire say is max psi at max load? Does it specify a minimum inflation pressure?
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