How much deeper is a wider tyre?

[mjr]

Do they do surface dressing in America? That's where the OP is doing his long ride.
A bit off topic, imo.

I think they call it chipseal in the USA and they're more inclined to leave the minor roads that the UK chipseals as gravel or stonedust roads. I've seen more bare concrete than chipseal in the USA.

 

[Ajax Bay]

Is there evidence that running mudguards with greater clearance between the tyre and the mudguard (generally but particularly the chainstay bolt fixing/seatstay bridge will make riding safer when 'surface dressing/chipseal' has been used on the route? That's why I suggest 'surface dressing' issues (which I agree are a pain and increase risk to cyclists et al) is off topic. NB thread is dealing with height of tyre in the context of whether it'll fit a frame. The limiting factor, in this context, is the chainstay bolt fixing/seatstay bridge. Without mudguards the width of the tyre in a frame tends to be the limiting factor. I have offered (above) a site which offers measurements of very many tyres' height (for the make/models' 25mm width version).