Honda's Service Manual for the 1800 (2001-1010) on page 1-11 calls for 36 psi in front and 41 psi in rear. I run 42/42.Dunlop E3 on '06 1800 with maybe 5k on tire.
Keep pressure around 36.
Center portion is noticeably higher than outer part.
I wet it down a little to show the wear better.
BINGO!!!!Doesn't Dunlop use a multiple compound in the E3 tire, harder in the middle for increased mileage, softer on the side for traction in the turns? a harder compound at the center may explain what your seeing on the centerline. 36psi sounds low to me also, I follow the tire manufacturer guidelines since fitting E3's to my bike, Honda's inflation guidelines are for the Stones.
Glad you're getting this ironed out. Always follow tire manufacturer's inflation specs before the vehicle. That's why tires are NOT covered by the vehicle manufacturer warranty, but the tire manufacturer themselves.
Forgive me if I insist on this. The tire manufacturer (on car at least) only tells you the maximum air pressure. I think is the same on bikes. It is your opinion that you should always inflate the tire to the max? In that case the car maker should say ” inflate tires to the maximum allowed by the tire manufacturer”. I’m confused.True enough, but the tire manufacturer DOES know what the tire is designed to carry and at what psi. Honda (or any other OEM) does not know from one manufacturer to the other. The specs Honda uses are what they think the bike should be used for at 'optimum' load and road conditions, not the real world. A difference of 4 psi over 10,000 miles is a huge margin under the stresses a tire is subjected to.
I just bought a new back tire. Got rid of the E3 with a little over 9000 on it. Cupped real bad and I didn't trust it with vacation coming up in a couple of weeks. 40PSI in the rear at all times and ride one up mostly. I'm not a hot rodder at my age. I just like to ride. I bought a Metzeler 880 this time so I'll see how it wears. My front is a E3 with the same 9000 miles and it's doing fine. I guess time will tell.Oh, and when the rear starts howling in the turns at 6-8K, that's normal too. My last set just shrieked in the turns. Sounded like an 18 wheeler in a hard turn.. Beyond noisy.