I'm so confused (okay, sorta)... 2.5" gravel tires? 13psi? That seems like a (soft, slow) mtn bike setup. I run my 40mm gravel tires at 40psi (I'm 178 lbs) and still have have (occasional) issues with rim strikes and pressure burps on fast rocky downhills.
Am I that behind the times/tech (it's a distinct possibility)?