Something like the PD RMP that clamps across the rails should work for you.

Thank you. Have ordered one of those, and will try it!

---

N+1
Strava

Zip ties and a standard bottle cage.

---

blog

Tried three different brands, x lab, PD and speedfil single bottle holder behind the saddle. None fit. The rails re just to narrow. Seems such a shame that ISM designed a saddle which does not fit any rear hydration system. Going to try the turbo wing now, but that really seems like overkill for a single bottle.

---

N+1
Strava

Is there a reason that zip tiews and a standard cage as stevej suggested, won't work for you?
I'm pretty sure the PN 3.0 chassis is almost identical to the Attack. I've previously attacked a Specialized Rib Cage to an Attack with zip ties without any problems. It's about the most minimal, lightest, cheapest and lowest drag systems you could use. Unless you need a position this won't accommodate, or you want a frame like a Turbo Wing to mount a repair kit to, there's probably no need to spend more than $20 total.

Incidentally, I've also used an Elite Skekane for rear hydration and that works with the Attack. It's not quite a s tidy a design as the Turbo Wing but does the same job just fine.

Xlab made a specific version for ISM Saddle like PN1.1&Attack: https://www.xlab-usa.com/delta-425.html
I think it's the same for PN3.0

On their compatibility chart it says it does not fit. Am going to try some zipp ties. If I cant get it rock solid, then a different saddle is the way to go.

---

N+1
Strava

I have talked to xlab and the only existing option that will work is the 2 bottle turbo wing and it has to be mounted on the horizontal part of the rails.

The PN3.0 rails (vertical part) are more narrower than other ISM saddles hence why existing options won't work.

---

blog

If your seat post has a 10mm thru-rail, you can use the TriRig Beta, which can be configured as either a single or double bottle holder. It is fairly adjustable in terms of how far behind the saddle you want it. I've been using one for a few months now with two x-lab gorilla xt cages and it has been flawless.

alexne wrote:

Tried three different brands, x lab, PD and speedfil single bottle holder behind the saddle. None fit. The rails re just to narrow. Seems such a shame that ISM designed a saddle which does not fit any rear hydration system. Going to try the turbo wing now, but that really seems like overkill for a single bottle.

That sucks. I've been considering changing my wife from the JOF55 to the PN 3.0. I hadn't looked at the rails closely before. They are tucked way under the back of the seat, almost vertical and as you've mentioned - narrow!

So the narrow width is what keeps the PD or Speedfil clamp from working - bolt spacing interferes with saddle rails?


From the images below it seems some of the carriers made from flat aluminum stock might be an option if they have clips aligned horizontally to match the vertical rails. Maybe any width difference could be handled with some bending of the aluminum. So something like the PD RML if it is long enough to clear the back of the seat. The Vision Trimax Rear mounts up in similar fashion, but is very pricey.


The fit trial and error adds up for cost and time. Too bad ISM doesn't have a recommendation. Most triathletes want to run some kind of BTS hydration.

it might be worth trying to bolt on whatever hydration you use. I have the pn1.1 which takes the Xlab mount and cage with the Aero pouch the 1.1 is also vertical but not as bad as the 3.0. I have been trying out the 3.0 on the trainer and was able to get the Speciaized hydration carrier to clamp, but its not perfect and not sure if it would hold on the road long term. I did get the XLab clamp for the 1.1 and think it should work for the 3.0 if needed. The problem with the 3.0 (as its almost the same dimensions as 3.0 int he rear) is the sides of the shell extend down in the back near those vertical rails which really prevents a beef clamp to get in there.

Exactly, that is what I am using and it is great, had it with the PN1.0 (Attack), and now with the PN3.0.

---

-Brad Williams
Website | Twitter: @BW_Tri |Instagram: @BW_Tri | Strava | Co-Founder & Coach at: KIS Coaching
Partnered with: Zoot Sports | Precision Fuel &Hydration | ISM

I think the Elite Skekane would work with that.
It's not fancy but it should be fine.

Using the same (on the Ism TT), depending on saddle position.....I drilled additional holes in the skekane, mounted it close to the front of the saddle and secured it with zip ties near the rear of the rails. Gets it very close to the saddle.

---

-shoki

I use a Profile Design cage (the type with the rubber band thingy to help stop bottle ejections), that is quite wide at the bottom corner. I drilled a small notch - just a few mms deep - into the bottom back corner of the cage and that sits nicely on the pointy bit at the back of my seat post. This base makes it nice and secure when it's secured laterally with zip-ties to my Adamo Attack. You can vary the position of the drilled notch depending on what angle you want the cage to sit at.
I don't see any reason it shouldn't work well even with slightly narrower rear-facing saddle rails.

---

-----
http://www.howesgreg.com

How wide are the rails apart? Was considering getting a PN 3.0 but this could be a deal breaker.

I have a Speedfil R3 that fits an Adamo Attack (which has near vertical rails too) so maybe this may work?

I have my PN1.1 fairly far back, almost maxed out. How far back can you adjust it away from the saddle? I’m curious if I can get the clearance if need. Thanks

Not positive, that would be a question for TriRig, but from what I have seen with it there is a lot of adjustability and I don't think it would be a problem.

---

-Brad Williams
Website | Twitter: @BW_Tri |Instagram: @BW_Tri | Strava | Co-Founder & Coach at: KIS Coaching
Partnered with: Zoot Sports | Precision Fuel &Hydration | ISM

I just bought the PN 3.0 and it is a great saddle. Same problem with a few of the rear mount units.

I managed to get it to fit my old Specialized Reserve Rack II to the PN 3.0.

The bottle cage will sit very close to the saddle thus I added some sponge tape to cushion between them.

Did you do any other mods than the tape? Do you have any experience with the specialized rack in terms of launching bottles etc.?

No other mods. Launching of bottles will have to depend on the bottle cage used.

Pics please!

---

Speed kills unless you have speed skills!!!

Won’t have any before March 17th.

---

-shoki

I have a similar problem with that saddle and the Minoura rack. The bottles point forward and the bars hit the saddle. A couple of minutes with a propane torch makes the aluminum soft enough to bend to make it fit. If you don't heat the metal, it will snap if you try to bend it.

Video - https://www.instagram.com/...aken-by=zentriathlon

---

----------------------------------------------------------
Zen and the Art of Triathlon. Strava Workout Log
Interviews with Chris McCormack, Helle Frederikson, Angela Naeth, and many more.
http://www.zentriathlon.com

Has anyone gotten the riddle solved yet? I really need to have hydration on my bike

---

Speed kills unless you have speed skills!!!

Here you go.

---

-shoki

I see, that's maybe the only way however on my SC the seatpost is a bit deeper than your a so I am not sure if it'll work!

I can't just rely on a BTA for hydration, specially when most of them leak like a mofo!!!

Damn ISM, make something to work on this saddle P-L-E-A-S-E

---

Speed kills unless you have speed skills!!!

Zip ties man. Zip ties. Cheaper and lighter.

---

blog

We had an unused Speedfil R3 laying around here that I was able to mount up to the PN3.1 yesterday. The clamps screws are just close enough to fit between the rails. Not sure how it holds up over time as it is all nylon.

If it was just a bottle cage I'd do the zip tie mount, but we're using the XLab aero pouch.

Been a few months, so wanted to bump this thread.

Seems like there's not many off-the-shelf options. I just ordered a Gorilla XT and some zip-ties. Will report back to see how well I'm able to get this thing mounted.

The $10 tacx mount works on this saddle. Can do 1 or 2 bottles.

Edit: looks like it’s a little more than the $10 I remember paying for it a couple years ago.

Tacx Behind the Saddle Water Bottle Clamp https://www.amazon.com/...cp_api_kXs1Ab9G83ZEF

Hey Sean, did that tacx one actually hold? I’ve heard some bad things about it not holding at the angle you set it at.

I’ve had the tacx on a Cobb randee for a couple years with no issues, 1 or 2 bottles including double 25 oz bottles.

Just got the pn3.0. One ride with it and no issues, just one bottle. Now I have gorilla xt cages. Just using the tacx mount, not tacx cages. I’ll try and post some pics.

Thanks Sean, great endorsement. Do you use lock Tite or anything else to hold screws in place?

Nope

This is an absolutely insane problem to have from a major manufacturer like ISM. I've got a PN3.0 on my ride after a fit a few weeks ago. I haven't paid for the saddle yet and may not keep it unless there's a resolution.

Does anyone have pictures of this zip-tie solution you speak of? It's so hard to believe, but I did ask ISM and they've just said sorry it doesn't fit.

Seriously dude? You are over reacting just a bit.

I don’t know how many times I have said it in this thread, use freakin zip ties. It’s not that difficult and it just so happens to save you some weight. Here’s a picture. Not the best photo but gives an idea. I can snap better photos late this week but I’m traveling right now.

---

blog

Noticed these Topeak offerings recently: https://www.topeak.com/.../products/tri-backup

Two of the Tri-Backup mounts are made for saddles with vertical rails at the back.

Delta wing worked for me.

---

Human Person

This works for you because of the angle of your seat tube and how your saddle is positioned on it. I don't have the same clearance from seat post to saddle rails. The bottom of the bottle cage hits the seat post before the zip ties are tight enough to hold things in place. You can balance it against the seat post, but it digs into the carbon. Just doesn't work with my bike. Need to find a mount that will work unfortunately. Thanks for the picture though.

Ok that’s fair. But this isn’t an ISM issue. The blame is not on ISM. It’s on xlab and other companies for not coming up with a solution to work with this saddle. ISM likely had to change their rail design specifically for this saddle design.

---

blog

What’s wrong with the tacx mount I’ve already told you guys about? It works perfectly for 1 or 2 bottles.

Thanks, Sean - I've been looking for a solution and am going to order this one from Amazon to give it a shot. Will report back with results.

One question - did you torque the bolts to anything specific?

Nope, just hand tight with small Allen wrench. Probably 15 ftlbs

Works good with the xlab turbo wing.

Since photo is broken, here's URL: https://imgur.com/a/mfeKE53

Let me know how you get on with it. I grabbed one from Amazon and it definitely doesn't fit. I suppose I could force it to tighten, but the sadlle rails do not fit inside of the recessed grooves in the metal plate. Blah. Still need a solution.

Sean - how did you get this to fit flush? The tacx mount I just bought has grooves in the metal that are narrower than the rails. Did you just force it tight?

Yes just screw it tight. Channel doesn’t have to fit between the rails to secure it.

Thanks man, this looks nice. Does everything sit nice and tight, i.e., is it fully compatible with the saddle?

Received mine a few days ago and tried to mount it yesterday. Doesn't mount, as you noted - I'm sure you could screw it tight per Sean's suggestion below, but there's got to be a more elegant solution...

Anybody look at the Profile Design RMP? Wonder if that would work.

Alex - Did you specifically try the Profile Design RMP / RML and can confirm that those don't work?

I did get a response from ISM on their facebook page. At first they said that they were not aware that no rear hydration fit. Then they said that this chassis was designed for road racing and not triathlon. Then a final message saying that they are in talks with some large hydration companies who have asked for measurements/formulation on this specific chassis.

So I guess something will be coming out eventually, I'd assume from x-lab. But I wouldn't guess any time soon. I'm going to just keep the Tacx jammed on there and hope it works!

Yes.. All good! Just torque the bolts to 5 nm or whatever the xlab said and it was good. Didn't loose any bottles and feels sturdy inserting/removing bottles. So I would say it's 100% compatible.

Side note: If you have the saddle all the way forward and there's a saddle clamp in the vicinity of where you're going to mount the xlab you MIGHT experience some issues.

Thanks man - this is really good to know. How's the Tacx holding up for you so far?

Fantastic. Thanks for the input!

So far so good on the trainer...haha

Have 80mi on Saturday outside on some suspect roads. I'll report back after that ride.

Awesome - would be curious to know how it holds up!

now that it's hot AF here in Houston, i have been riding regularly lately with 2x25oz bottles on the tacx. no issues.

Put the TACX on last night and did 90mins this morning with no issues. Ran single bottle and had no bouncing or looseness.

Given the shape of the IA seatpost and the position of the saddle on it the Tacx bracket did not fit for me, so the only option is the Xlab Turbo Wing, which fortunately I had laying around from a few years ago. I mounted it up on the vertical rails and it seems rock solid.

[URL=http://s1261.photobucket.com/...zps6ejhkx8a.jpg.html][/url]
[URL=http://s1261.photobucket.com/...zpswslh5ena.jpg.html][/url]
[URL=http://s1261.photobucket.com/...zpspieksepo.jpg.html][/url]
[URL=http://s1261.photobucket.com/...zpsvlmxym96.jpg.html][/url]

Noticed over the weekend that alistair is. Is running a pn3.0. This is probably the best solution I’ve seen due to the angle. Anyone know what mount this is:

https://www.instagram.com/...igshid=1bknxp8icsry3

---

blog

The Xlab Carbon wing has worked great for me all season on this saddle. 2 large bottles in gorilla cages on some very rough roads and never had an issue with anything coming loose or ejecting.

I think I've solved this issue, in case anyone's still looking. It's the Tacx "Cage Mount Carbon." Pics below. You can change the angle with the pivot, which seems pretty solid. You also can adjust the height lower by swapping the mount so that the long side is downward. Note that technically this mount is attached to the seat rails upside down, but it works fine. I've zip tied it around the saddle for extra security, but I'm not sure it's needed.

Incidentally, it's the very narrowness of the up-angled rails that makes this mount work in this location.

It comes with both 1-bottle and 2-bottle mounts.

---

--
Follow my endurance sport antics and ruminations on my blog, http://www.rememberingjaron.com.

Another angle.

---

--
Follow my endurance sport antics and ruminations on my blog, http://www.rememberingjaron.com.

Hi, I have the 3.1
I use giant support, I find it very good.
I only had to make two more separate holes in the support, on one side are already marked to make them, and the inside of the seat that is made of metal, aluminum is easy.
I leave you three photos

https://drive.google.com/file/d/1K7VQYEgHLIdp68h82_O_GKL9F1m_qh3Y/view?usp=sharing


https://drive.google.com/file/d/1VyXBkrccs2g9fHB7pxqXiuELrPPXLJ4q/view?usp=sharing


https://drive.google.com/file/d/1s-YGQ6HCT1iz6fqtSlMz-mQIgLjlTBl7/view?usp=sharing

I was able to get the xlab Super Wing attached to this saddle, despite being listed as incompatible. It wasn't hard. I put it in a vise and removed some of the flaring so that the attachment arms were parallel and more narrow. I'd still like to attach my Carbon Wing instead, but I'm not sure if the carbon model can flex enough without cracking.

with your seat post why not just put a tri rig beta on there?

---

2019 T-Rex Tri Series

Yes that could be an option. However I was switching from ISM Prologue with which I was using the super wing and then the carbon wing so I already have those on hand. You can see in one of my photos that I also have a small xlab bag mounted in there, which the Tri rig beta would not allow, to my knowledge, except for underneath which is a design I’ve moved away from. I’ve also invested recently in the xlab rear repair assembly, which would not fit behind the Tri rig beta mounts.

I have some cheap chinese alloy BTS mount I have used with ISM TT and it turns out that it fits PN 3.1. Screws almost touch the rails. I haven't tested it outside yet but it holds firm.

Topeak TRI-BACKUP PRO I - It’s a single or double bottle cage saddle mount that fits on pn 3.0 / pn 3.1

I’m using it and love the adjustable height option and attachments available. The reverse cage design of their TRI-CAGE CARBON is also a very nice option.

https://www.topeak.com/.../products/tri-backup

But why just not put the dedicated PN3.1 / 3.0 from xlab, the delta 430?

Jeroen

---

Owner at TRIPRO, The Netherlands

Cause that thing just got released a few days ago.

---

blog

I got a 430 and it works perfectly.

Topeak has a new mount that accommodates a variety of saddles. We use the current (now older?) one and it has been rock solid, but the new ISM 3.1 saddle with the vertical rails doesn't work. I'm about to buy the new one; I'll post here if it works.

https://www.topeak.com/...9-TRI-BACKUP-ELITE-2

Also, since we got their bottle cage with the mount, it is now the only cage I recommend to friends, because they stop your bottle falling out by cupping the lower side. Simple in hindsight. I point this out because the new mount also shows a new cage with a rubber ring around it, which appears to keep the bottle tightly held. Great for those small bottles they are using at Kona etc.

Webdog, wondering if you have purchased the Topeak Tri-Backup Elite 2 and if it works on ISM saddles. I'm in the market for a new rear bottle cage (I have an ISM PN2.1) and am intrigued by this one. TIA.