That's all I go with. If it requires more than that to fix, my race is over anyway

I'm not at the pointy end of races, so I take the view that the extra few ounces and maybe a few Watts drag is worth it vs a DNF, if I'm on a half or full IM after all the training and cost.
So I've basically got what you say but got a tool that includes a chain breaker (i got reasonably small flat stainless steel Lezyne multi tool).
(Actually I rake 2x Co2 in case the 1st goes wrong. See Chrissie Wellington's problem at Kona !)

Out on 'normal' rides Ive found I've used the chain tool a few times ,(mainly Mtb after incidents) but inc where the chain went down the side of the chain ring and jammed, and was NOT coming out without breaking the chain and unthreading it.

Oh I also carry a spare power link to allow quick re-joining after a problem. 3 grams is not going to lose anyone a race.

I broke a chain once on a training ride. So, I carry a Crank Brothers multi-tool along with my tire repair stuff. Plus, that doubles as a general purpose tool if I have any mechanical issues on-site, before start. The weight is minor, and it fits. If I break a chain, I won't finish in the top of my AG, but I still I prioritize finishing over micro weight savings.

That's basically what I carry: 1 tube, two CO2 cartridges, CO2 inflator, a tire lever, and a multitool.

same here.

much less tools/spares needed if you use tannus solid tires.

Would I need to carry extra water since I'll have longer on course?

1 tube, 2 CO2 cartridges, CO2 inflater, patch kit, 2 tire levers, 4 and 5mm allen

+1

1 tube, two CO2 cartridges, CO2 inflator, a tire levers, super glue patches, and a short length of duct tape with sticky sides stuck together (in case of a sidewall blowout)

---

---

---

Take a short break from ST and read my blog:
http://tri-banter.blogspot.com/

You could fill up the used CO2 cartridge with water... 2x 16g should see you through.🙈

1 Tube
1 CO2
1 Tire lever
Small pack of adhesive tire patches
1 Micro pump

Basically I want to make sure I can get to T2 even if I were to get multiple flats (thus the patches and pump). Other mechanicals (broken chain, broken spoke(s), etc.) and it's sag wagon time (can't carry a whole bike shop). If I did need a boot for a tire, I'd just use an empty gel sachet.

For training, my flat kit also has a multi tool, spare quick connect chin link, and nitrile gloves.

---

ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

I also have a couple of old cleat screws and for a full IM I drop a spare (old) derailleur wheel and bolt. Ok, it's overkill but I typically race with my normal long-day kit

1 Tube
2 CO2 can
1 Adapter head
1 Pack pre glued patches
2 Tire lever
1 Powerlink

---

Full-time Engineer / Part-time Pro Triathlete
Instagram - https://www.instagram.com/benwgoodfellow/
Strava - https://www.strava.com/athletes/3085032
Website - https://benwgoodfellow.wixsite.com/bengoodfellow

I'm at the FOP pointy end and just carry a spare tube, CO2, levers and inflator with an allen wrench to get my thru axle off.

I've probably put in 4000-5000 miles outside a year and I only have had one chain break on me. That was due to inadequate maintenance the first year I had a nice bike.

Usually two weeks before an "A" race I replace my chain, check my tires, etc.... My thought is that if I'm constantly checking things, they aren't likely to get to far out of whack on race day.

Or, if things are going that far out of whack that I'd need those items, I probably don't need to be racing the rest of the day because of bigger issues.

You'll also lose enough time on a 70.3 that you can likely change TWO flats and still come out ahead on race day! (I say this as a regular Tannus user and fan of them - for training!)