Rain and wind (and I suppose elevation) are your biggest uncontrollable enemies. Rain makes a very big difference - it's physics and it's a fact. You've certainly got me concerned. That's a very high average. If you compare unfavorably to other MXs (hopefully they'll chime in), you can check tire pressure, alignment, and most certainly schedule a service appointment. 425 is, in my view, unacceptable. I average 296 in my MS over 30k miles with lots of varied road trip terrain and weather.