[Q Tech]

We won't know until someone has one and can measure clearance for both diameter and width...one of those measurements is severely limiting.

So if the most pessimistic scenario is that 7.8' gc is all we get what would be a moderately optimistic scenario as far as possible ground clearance with different tires? Would 8.5 be out of this world?

265/60-18 like on the Auto show trucks should net very close to 8.5" I'll be installing a set right away and will report on fitment.

 

[Q Tech]

I am by no means a tire expert. The standard tires that come on the 2017 Ridgeline are 245/60R18. In order to increase clearance, I think you'd want to go down in aspect ratio size to something like 245/50R18. I'm not sure that this would be a very big difference, just wildly guessing, it might be an inch. Someone with more knowledge than me will have to comment on that. I recommend sticking with the 245/60R18s. Honda selected that 60 aspect ratio as a nod toward preserving tire clearance. Of course, I don't know jack about offroading. My gut just tells me that making the tires more low-profile makes them harder and perhaps reduces traction on softer paths. I have a set of brand-new 265/60R18 snow tires that I've been wondering about. My understanding is that they may reduce clearance slightly.

You've got it backwards. Google it.