As the course has changed pretty much every year, it is hard to say. That said, the numbers of athletes has been less than 1500 the last few years (if I recall) and so it should be pretty wide open despite being 2 loops.

Can't help with he altitude question, as I was born and raised at higher elevation, and so it doesn't really bother me until it gets over 8500ft.

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Did it in 2016 and never noticed large packs form but there were a couple of pairs working together at times. It is well marshaled and with the climbs I don’t think you’ll see big draft issues.

I don’t know what changes they have made to the course to be able to say if it will have any impact. The biggest issue was the traffic on 36 north of town and the narrow lane to ride (fatality in ‘16 when a lady rode out of the cones and got sideswiped by a car) .

As for altitude you’ll notice it in the swim more than anything else. Bigger issue will be heat which can be hit or miss in June and sun at the elevation actually more strong than you would expect.

Thx for your answers guys,

sounds like it may be a go :-)

Born at sea level and lived in boulder for a year, it still kicks my ass everytime I go back. The elevation is real

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Team Zoot 2023

There are a few short sharp hills to break up packs. But you'll see some drafting in the first 10 miles on 119. The good news is that this race actually has draft marshals so at least the penalty tents will have some people in them

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The first year I witnessed three guys in green/red/white outfits (all the same team or whatever), with "Mexico" all over it, working together in a team TT like format & leap frogging up the road. That was about the worst. Other than that, only a couple instances which were up near the front of the AG packs of cyclists. It was all quite minor and isolated. In general, it is one of the better (least drafting) races I've seen.

The worst? Has to be Kona. That have serious issues in Kona & need to fix it asap. But Boulder--I'd say it's pretty fair.

i have seen the marathon elevation chart. it doesn't seem to be a "fast" marathon. do you have specific short climbs or just long steady climbs as it seems from the chart?
did someone notice a slower pacing due to altitude?

I've raced and spectated the 70.3 in Boulder two separate years and didn't notice drafting issues though that doesn't mean much.

Altitude, will start by saying that everybody is different BUT:

1. the swim - yes you'll really feel it, but if you do a shake out swim to get used to that feel, it's not bad on race day. My husband and I swam our normal times there, and my IM swim PR was at Lake Tahoe, so I don't think this has to be an issue if you're mentally prepared
2. the bike - less air resistance at altitude is great for smaller cyclists like myself, my full and half bike PRs are at altitude
   
3. the run - you feel it more at the more intense paces, so should be less of an impact to IM pace than for shorter distances, the bigger issue as someone mentioned is that the heat and sun intensity are amplified at 5k ft. I would worry more about how you'll combat that than the O2 effect (since you can't do much about that anyways :)).
   

Science says that ~48 hrs is good window to arrive pre-race, before your body acclimates, which is what I've done in the past when racing at altitude, and it hasn't been terrible. Takeaway: get there 2 - 3 days out from race as you normally would vs trying to do a week early to acclimate - giving your body that 5-7 days is actually worse since the process is underway.

I've been assured by DC that Boulder will be well-marshaled this year. The plan for marshals on motorbikes has been approved by the authorities.

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Ed O'Malley
www.VeloVetta.com
Founder of VeloVetta Cycling Shoes
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