Free the Rear Hydration System
We are fast approaching the scheduled implementation date of World Triathlon’s updated hydration system rules. For those who need a refresher, here’s the basics of what has changed:
- For front hydration, there is a maximum allowable capacity of 2 liters. Bottles can either be mounted forward of the steering axis, or along the top-tube. They must not cover the arms nor the steering axis, and the mount can be no taller than 10cm above the top tube.
- For rear mounted hydration, the mounting hardware, cages, and container must fit within a 30cm x 30 cm box that begins with the rear-most edge of the seat post. Bottles can extend beyond this box. There is a maximum allowable capacity of 2 1 Liter bottles. Exceptions are made for Race Ranger units in this 30 x 30 box, as the seat post is where the rear sensor is mounted.
This seems simple enough, until you get into the exceptions for rear hydration systems. Because it’s now gotten very murky — and impacts far more riders and manufacturers than previously thought.
The specific language from World Triathlon (which, for what it’s worth, then covers all events globally that fall under their ruleset, including IRONMAN), says that for bikes with hydration systems integrated in the frame, those systems:
- may be larger than 30 x 30 cm
- may not contain more than 2 litres in total
- must not protrude beyond the vertical line through the rear axle.
The interpretation document then says that “on bicycles with hydration systems that are integrated into the frame, no additional attachments may be added to the rear of the frame.” When we first reported on these rule changes in April, we were under the impression that this would cover bikes with any internal frame hydration system — think of the Ventum One, the original generation Specialized Shiv, among others.
However, it has become apparent, following conversations with various entities, that the interpretation of “frame mounted system” is to include any integrated rear-mounted storage system. This means additional bikes, like any of the following:
Quintana Roo, PR-series or newer
Scott Plasma
Felt IA
Orbea Ordu (pictured below without the rear box)
Specialized Shiv TT or Tri
Trek Speed Concept
BMC SpeedMachine or TimeMachine
There’s too many to count. If you own one of these bikes, you now face an either/or scenario: you may either carry your rear storage box, or have rear hydration, but not both.
Let me be unequivocally clear: this is insanely stupid.
We get the underlying matter: triathlon is trying to catch up to the trends of hydration as fairings, which reached near-comical ends between Camelbak’s stuffed in jersey’s and Joe Skipper’s infamous cockpit. But it is also high comedy that, nearly 15 years after the integrated frame hydration started, and more than a decade since the launch of the integrated rear tool box, we’re now going to start banning the ability to have a traditional water bottle mounted behind the saddle if you happen to have one of these other items.
It’s particularly egregious when race producers are also becoming more restrictive with either aid station counts, or moving to refill stations instead of traditional aid stations, or offering hydration on course that is limited in carbohydrates. It hurts everyone from riders forced to modify their bikes to race officials attempting to enforce a draconian ruleset to companies now forced to scramble to solve for a problem that did not exist until a month ago. It is, in the words of Lord John Marbury from The West Wing, “exceedingly stupid.”
To date, Challenge Roth is the only race who has announced a variance to the rule, and it is only for the one race (not all Challenge events).
The rule should be simple: you can have a maximum of two bottles up front, two bottles out back. The rear ones must be standard bike bottles. And you can have a rear mounted frame storage so long as it fits within a certain scalable box based on frame size. It’s water bottles, people. It’s not hard. And if it’s really questionable, you always have referee’s discretion in the back pocket to justify removal (e.g., you can’t 3D print something at home).
I hope that someone can come to their senses.
Didn’t @Ajax_Bay already post the Ironman rules which does not include the 30 by 30 box on the back, it just limits the carrying capacity to two liters?
A key message here is also safety. I can either use the materials that came with my bike, or I can MacGyver something into the 30x30 so that all my hydration and flat kit fits.
Can I make it work? Yes
Will it be as safe as just letting me use my Speedbox? No
And nobody has answered how THIS isn’t considered a fairing.
Yes! Aid stations are getting reduced which I really don’t care about as long as I can be self sufficient. I was a boy scout coach, I’d like to prepare for every eventuality!
And I was also really happy with my frozen slushy hydration belly bladder thank you very much!
We understand that IM is following the WT interpretation.
What does that mean? Did you speak with Jimmy? Could be more clear?
It means that at this time… Ironman is planning on going with this really stupid rule…
As per Ironman directly today? We know they haven’t said anything about the rule yet but are we just assuming they won’t or did they tell @rrheisler they are not?
Currently until Ironman says they aren’t… They are… Because until they say they aren’t… their rule books says they follow the WT Rules.
OK, understood. But this isn’t new, we have two threads at least on the topic. Maybe it’s just me but I read this as the final decision as Ryan had said he was reaching out to Jimmy for clarification. So to be clear, you have NOT spoken to IM about our concerns on this issue and received a response, correct? I’m not trying to be pedantic.
Sorry, but that is incorrect. The first sentence in their rule book specifically says otherwise
The official Ironman rule per the published 2025 rules update are as follows:
These rules have not been amended so they are the rules that are currently in effect. Jimmy may be communicating they are planning another adaptation of the rules to ya’ll in private, but your statement fully contradicts their published rules.
adding source which includes a link to the 2025 competition rules. 2025 IRONMAN Competition Rules | IRONMAN
I confirmed that it is a correct interpretation that you either can have a box or a bottle, but not both. Per Jimmy.
Just to be clear: Will this apply to pros and age groupers, or only pros (since as far as I know, only pros have been notified, through that email a couple weeks ago)?
Everyone.
Gotcha, thanks. It’s frankly insane that we’re presumably three days away from these rules being enforced without an official announcement or amendment to the rules from Ironman. To @marquette42’s point, if I went to Ironman’s competition rules page, and read those rules, and followed those rules, and then went to my race and got disqualified because of a different set of rules… I’d be pissed.