I find different ISM models to be light years apart. I have the breakaway which has a longer nose that tapers down slightly narrower than the road, race, or TT models. I haven't tried the attack or the prologue. I know that the nose of the Dash measures the same width as the nose of the breakaway. I did that bit of research because I have been kicking around the idea of trying one. My hesitation was that right now "it ain't broke" so I am a little afraid to "fix it".
FWIW, I can't ride the ISM saddles at all on a road bike because the slack seat angle encourages sitting further back on the saddle and engaging the seat bones. When I ride my TT bike, the steep angle allows me to literally hang off the nose, rotate my pelvis, and hammer down and back. It almost feels like I am hooking the seat bones over the nose and hanging from them like a towel on a hook. If I go on a group ride where I am not in aero, all the saddle problems crop back up but of course so do a bunch of others because my bike is set up for an aggressive TT position and is a miserable animal when ridden like a roadie. I cannot comfortably ride in aero on any other saddle but the ISM though. I went to a cycling center that had a bunch of test models. Tried about 10 different saddles on a computrainer, picked one, took it on trial, and bought it a week later. There was very little difference in the appearance of the models I tried but the feels were worlds apart.
The Dash holds a LOT of appeal because it seems that it would all that aero position but drop the weight of a VW bug (ISM's only real drawback).
One big caveat... there is no piece of equipment more subject to personal preference and anatomy than the saddle. No matter what someone says should work, it's meaningless if it can't pass the comfort test. You must be comfortable or it will inhibit your ability to produce power. That doesn't mean it should feel like your favorite pair of jeans. It means that when you are working, it should not be getting your attention. Also, anytime you change anything on a bike, there is a cascade effect throughout the whole fit. If you move the saddle, angle the saddle, change the crank lengths, switch your aerobars, it will all have an effect on every other aspect of your fit. If you are finding that you have tried a million saddles and nothing is working, go back to the drawing board on your fit. I had to scrap everything and start over with a sizing on a fit bike, buy a new bike that seemed to be an illogical size but followed the numbers and go with very short cranks to discover how comfortable a saddle I already owned really was.
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Coach Brain: Accelerate 3 ;
Incoherent Ramblings