ISM PN 1.1 – Review

When ISM released the Attack two years ago, it was very nearly an overnight sensation. The narrower profile meant that those who previously had to zip-tie the prongs of a Road or Prologue had an off-the-shelf solution to thigh clearance problems. The ability to push the saddle further forward let triathletes who once were limited by their seatposts get that extra handful of millimeters of forward travel along the saddle rails, which can, for some, mean the difference between bliss and agony over the bike leg of an Ironman. The only complaint about the Attack we had heard was that it could do with a touch more padding, and with the release of the PN1.1, we suppose that ISM got the message loud and clear, too.


The PN1.1 is the second in a series that ISM is calling “Performance Narrow” – hence the designation “PN” in the model name. The dimensions of the saddle are virtually identical to the Attack, now considered a member of the PN product line, but with significantly more padding and a swap from the Attack’s titanium rails to satin steel. The materials change in the rails is a cost-savings measure, and though it does come with a weight penalty, it is also a full $100 cheaper. For what amounts to the weight difference of a bottle cage and bolts, a rider can pocket a cool Benjamin; we think many will be perfectly happy to make that trade.

What may be the make-or-break for the saddle, however, is the padding thickness difference. The Attack uses something ISM calls “25-series foam and gel,” whereas the PN1.1 utilizes 40-series. The 40-series offers the same level of plushness found in the Prologue, where the 25-series is a little firmer than the Breakaway. This difference is what really separates the two saddles from one another. The Attack is, at its core, a dedicated race saddle. It is comfortable because of its shape, not in spite of it. The PN1.1 has a plush quality to it, in that you can feel your body settle into the cushioning of the saddle. It also has a much larger contact area than the Attack.


This is a great time to stop and talk about the correct setup of ISM saddles. All too often we hear from riders who aren’t taking advantage of their saddles due to incorrect positioning, which can result in pain and discomfort. If that sounds familiar, Greg Kopecky of ISM is here to help you out.

According to Greg, “the front arms of ISM saddles match the shape and angle of the pubic rami bones, so the rider can sit on them, rather than the soft tissue that falls in-between them (which contain nerves and arteries that lead to the genitals).  The reason people put zip ties on ISM seats is that they have not set them up according to our instructions – namely, not pushing the seat far enough to the rear.  Some fitters don’t understand that we have eliminated the “nose” of the seat entirely, so the seat must be placed significantly further to the rear than traditional seats.  It’s not that we’re moving the position of the rider compared to a traditional seat; we’re just getting the seat out from under the soft tissue area.  The effective seat tube angle remains the same.  This page covers all of the specifics:”


We think the PN1.1 will be a good solution for riders with especially troublesome soft tissue issues that require something with a larger distribution patch than the Attack affords them. For those who enjoy the Attack, however, the extra padding adds additional pressure to their perineum, and that simply isn’t going to be comfortable for a rider who is accustomed to sitting on their true sit bones. This also leads us to a second point that Greg raised with us.

“The other thing I wanted to touch on is the issue of sit bones.  This subject gets talked about a lot, but the reality is that – especially on TT/Tri bikes – the rider does not sit on the sit bones (ischial tuberosities).  As the rider’s pelvis rotates forward, the sit bones lose contact and pressure with the seat.  With traditional seats, the weight shifts to the soft tissue area; with ISM seats, the weight shifts to the pubic rami bones.  When a rider is very upright – such as on a hybrid bike – the weight is definitely on the ischial tuberosities.  The more forward you rotate, the less your weight is on the ischial tuberosities.”


Generally, we fall into this second group of riders. The Attack works for us, while the extra padding of the PN1.1 is ultimately unnecessary. And we think that’s perfectly acceptable. After all, if the Attack or the PN1.1 worked for everyone, we wouldn’t have anything to discuss. During our rides with the PN1.1, we found it to be plusher than we were used to, but noted that it is the perfect saddle for someone who isn’t accustomed to—or simply doesn’t prefer—rock-hard race saddles. ISM’s latest saddle is an excellent introduction to split nose, for those suffering from soft tissue problems, or anyone who simply can’t get comfortable on harder saddles like the Podium but still require a pressure relief channel.

The next in the Performance Narrow line is the “2.0,” which is triathlon specific and significantly racier than the PN1.1. It will incorporate the titanium rails of the Attack, as well as a triathlon hook on the rear. It will also offer significantly less padding than the 1.1, bringing it more into line with the Attack in terms of aggressiveness. As for the PN1.1, our recommendation is simple: go to your local bike shop and enroll in their demo saddle program. The only way to know if a saddle will work for you is to try it out. Although we think if you liked the padding of the Prologue and the profile of the Attack, then it’s a fairly good bet that the PN1.1 is the “just right” saddle for you.

[Updated 6/2//2015 with more information regarding correct saddle position for ISM saddles]

6 responses to “ISM PN 1.1 – Review

  1. It seems good equipment reviews should include references to benchmarks. Industry best in class products likely offer analysts a meaningful point in determining value. Name the competition.

    Most reviewers of ISM Adamo dance around the subject of weight. Please state the weight. Report the MSRP. Why make your fans think you’re just advertising?

    ISM Adamo long viewed the triathlete’s beat friend has yet to design a saddle which is just for us eschewing UCI limitations. Or for that matter a design of carbon and light in weight.

    I enjoy and appreciate your work at AeroGeeks but reviews without the details are suspect and ultimately send us back to forums which share the good bad and ugly.

    Go Get It!!!

  2. FWIW the PN1.1 sitting on my desk weighs 396g. Not especially light, but really could care less if it lets me ride a more ‘tucked’ position.. TT rig isn’t for climbing alps after all 🙂

  3. Could you include a table showing what narrow / wide and padding option combinations are available, preferably with some measurements? Otherwise it’s hard to understand the model line up.

    • Hi Andrew – we reached out to ISM to help out here.

      V “Yes, we do have charts that explain this, called ‘Help Choosing Saddles’:

      The charts don’t have the written widths of the rear of each seat, simply because there is so much info already on the charts, and we don’t want it to be disorienting. The Narrow seats are 110mm wide, the other performance seats are all 130mm wide at the rear. The width info is also on each individual product page.”

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