IRONMAN Tweaks Drafting, Cycling Equipment Rules for 2025

[E_DUB]

of course you are already thinking about this haha You are the worlds best tinker Hope all is well.

[Ajax_Bay]

@rrheisler

Correct. You can have two bottles up front, two bottles out back for a total of 4 liters.

Pulling this across from the other thread (which is the IM Pro Series 2025 thread, IM Rules is peripheral (but Rules wef first IM Pro Series race (deliberately). Will Skipper have a final bottle sing-song in Taupo?

@rrheisler

Oh, you haven’t seen some of the fun with people throwing mounts on stems, or steer tubes.

All said, they’re trying to cover every base of “stop trying to fill every single gap between your body and the bike up there with bottles.” The intent is pretty easy to suss out.

@Tigre

but how do you explain « top tube » in the list?

I’m going to assume the rules drafter knows the intent but maybe struggles with language. The thrust is obvious but the intent is to head off (proscribe) bottles attached to occupy the space under the rider’s chest. So while mechanically the top tube (and indeed the head tube or the frame itself) cannot be described as a "rotating around the steering axis” the drafter has lazily lumped them in. A better draft might read:

"Systems mounted to components attached to the front part of the bike (i.e.: top tube, head tube, headset and those that rotate around the steering axis (bars, cockpit, stem and fork)) must have a combined volume capacity of no more than two (2) liters”
(Attaching stuff to the downtube inside the triangle is OK’d in a subsequent sub-sub-paragraph.)

[rrheisler]

I almost pulled those posts over into this thread…but here we are.

I think Skipper can still use the two aero bottles over the arms if he so chose; so long as it maxes out at 2L.

They could have made this clearer than they did. However, what happened (as part of the rules harmonization with World Triathlon) is they took the existing language from the WT rulebook and added “top tube” to it.

From the WT book:

“Hydration Volume Limitation: Hydration volume (e.g. bottles or hydration systems) mounted to components that rotate around the steering axis (e.g. cockpit extensions, basebar) must have a combined maximum capacity of 2 litres”

They tried to make it more clear and, well, here we are. But it’s also not hard to read the intent into the rule, which provides clarity to the situation.

Anyways.

[kajet]

@rrheisler

I think Skipper can still use the two aero bottles over the arms if he so chose; so long as it maxes out at 2L.

I think he’s already talking to someone about making a hollow cylinder capped on one end.

Here’s your half liter bottle with the outside dimensions of a one liter bottle, just longer/thinner than this and with less hollow space (you want to drink, too). For the avoidance of doubt: the fluid storage is between the inner and outer walls of the bottle.

[monty]

@kajet

I think he’s already talking to someone about making a hollow cylinder capped on one end.

First thing I though of reading this rule was you can put a liter in any size bottle you want. If the actual rule is what it holds, then it is stupidly written. I would just make a bottle with a light foam outer to any shape I want, keeping the available inside a liter… Did I miss this workaround to the rule somewhere??

[Lurker4]

@kajet

For the avoidance of doubt: the fluid storage is between the inner and outer walls of the bottle.

The rules allow the head ref to deem that illegal on the spot. Lot of effort for nothing.

[Ajax_Bay]

@Lurker4

The rules allow the head ref to deem that illegal on the spot.

Whatever Ditlev was planning in Kona was bowled out by that ‘Head Ref decides’ catchall.

[kajet]

@Lurker4

@kajet

For the avoidance of doubt: the fluid storage is between the inner and outer walls of the bottle.

The rules allow the head ref to deem that illegal on the spot. Lot of effort for nothing.

Fair point, though does it mean athletes won’t try?

Also my idea was really crude and over-engineered. There are better ones. What @monty said. A big bottle need not have big capacity. You could use a thermal bottle with plenty of vacuum between the two layers of the wall. Fill it with drink and ice. It’s a hot day of racing!

[timbasile]

@kajet

Here’s your half liter bottle with the outside dimensions of a one liter bottle, just longer/thinner than this and with less hollow space (you want to drink, too). For the avoidance of doubt: the fluid storage is between the inner and outer walls of the bottle.

Is the whole thing supposed to go between your arms and your chest, or is this a fairing that covers the hands? Where is this supposed to go, exactly?

[timbasile]

One of the other quirks with this rule is that you can be in violation of it sometimes (at the start) but potentially not at others.

Front: 2L max, total
Back: 2x 1L max

If I’m running 3x 650ml bottles up front and 2x 1L behind, can I swap one out midway through the race?

I’ve started the ride in compliance, but I can move things around as I’m drinking, and suddenly I’m breaking the rules?

Now obviously most people are either going to use a reservoir that refills or the same size bottles everywhere, but the rule is a bit funny in that they’re not harmonized against each other.

I’m obviously bring a bit obtuse, but the front rule should really read: limit of 2 bottles or containers, and up to 2L total.

[TheArchitect]

Considering this bit:

leading edge of the front wheel

Since we’re nitpicking, is that the leading edge of the front rim, or the leading edge of the front tire?

[kajet]

@timbasile

Is the whole thing supposed to go between your arms and your chest, or is this a fairing that covers the hands? Where is this supposed to go, exactly?

Between your hands and your chest, or between the top tube and your chest/belly. Better answer though: wherever Joe Skipper decides to put it

[The_GMAN_Retired]

@TheArchitect

Considering this bit:

leading edge of the front wheel

Since we’re nitpicking, is that the leading edge of the front rim, or the leading edge of the front tire?

Wheel, I think by definition, does not include the tire. So strict letter of the law would be the rim in your question.

[The_GMAN_Retired]

We are fussing about the water bottle BS which will likely affect few people when the drafting rules change is a WAY bigger deal.

[timbasile]

That’s because all we really want to know is how/where do we put said bottles for maximum aero advantage.

[Velocibuddha]

@gunna

Only 3 mins penalty for drafting… That’s going to pose a interesting value proposition for cheats to weigh up…

It’s ridiculous.

Benefits of drafting - huge!!
Penalties for getting caught - tiny.

[rrheisler]

We discussed this a little on the podcast, though – I think by reducing the infraction amount, it will likely empower ref’s to choose to penalize versus not when they think of fringe cases. And who knows, that might even mean somebody earns two of them in a race (and you don’t risk a third, as that’s a DQ).

[Lagoon]

Is there a new pod I missed? Or is this from a conversation last year?

[rrheisler]

Thought it might publish yesterday. Looks like you should check your feed later today.

[desert_dude]

@The_GMAN_Retired

Wheel, I think by definition, does not include the tire. So strict letter of the law would be the rim in your question.

I would not be surprised though if the refs just use the leading edge of the tire for simplicity sake