first of all, I realize my blah blah is disorganized and as usual, overly long......apologies.
secondly, I realized that I should have done the inner measurements. The day I did all the photos, I had taken off and put on a whole slew of tires, replacing a tube, trying this rim out and that rim out, and realized afterwards that I screwed up and didnt take photos of inner measurements...
* just measured my rims, black Mavic 717, and they are only 17mm inner.....so according to the chart you mentioned, that I added here, I'm past the "safe" limits, but apparently others have safely gone past this, like I can attest to.
Tourist what are the actual widths of your 57mm Extremes on your 19mm inner rims?
re handling that you mentioned, "
The inner width of the rim is only 19mm and I have found at low pressure a 57mm wide tire lacked stability and handled poorly." it does make me realize that this is a tricky thing to evaluate, this "feeling" we have with a tire at a given pressure.
I do know with the 2in Supremes, when I'd have the pressures lower for really rough or soft stuff, and then was back on pavement and going either fastish or around corners, I could feel the tire moving around a bit, and it would immediately feel better bumping up the pressure just a bit.
this is pretty standard and normal, and the actual numbers of psi so much depend on rider+bike weight.
I can say though without hesitation that for me, the 2" Supremes at proper pressures on my "too narrow" 17mm inner rims, gave me the best handling bicycle around corners that I've ever ridden, so I actually can't fault running them on this size rim.
I'm certain that I've mentioned this before, but I was able to corner to the point that I was even confident moving my body slightly off the saddle mid corner to get my body weight in and down, like in the motorcycle days. Yes, it was just a small amount, but just to show that I was very confident in how the tires felt (not moving around) with fast cornering and due to the construction of the tire sidewall, the "suspension effect" over bumps and whatnot mid corner was consistently good and linear--ie, not any weird feelings.
I dunno, but if for future rim choices, I think I best stick with something like the Alex Adventurer 2 rims that came stock on my wifes Troll, 21mm inner width. The bike came stock with 2.5" Extraterrestrials, and given that I can't see ever using tires under 1.5", this probably would be a safe bet for many tire options.
