Tire pressure Marathons Green guard

[Bernard Duhon]

I have 650 b Marathon  green guard 42 mm ,weight W/bike 180 pds 

Purchased nearly new on 650 b list.

I use the bike exclusively for urban riding/errands .  Rail road tracks broken cheapseal glass & metal.

So they are a rough ride.  But I "never" get flats.  I should not say that!

My solution is run em in the low 20s  

 

Some online wisdom is that I will be breaking the side wall threads due to "excessive" flex .

What do ya'll think?