From the course description:

"The 42 kilometer bike leg is a course that has a little of everything as it winds through north Boulder County. A About 6 miles into the clockwise loop will ascend 15% Old Stage Hill (600' vertical climb in 2/3 of a mile). On the summit will be the first fluid replacement station. From Old Stage it is a beautiful descent down Left Hand Canyon and out onto the Buffalo covered plains. Now, in its third year, B a 35mph speed limit will be strictly enforced on the major descent on the backside of Old Stage Road. We will have police officers and course marshals monitoring this.

A: Their math is a bit off. Elevation Gain / Length of Hill = % Grade. So 600' / 3,485' (2/3 of a mile) = 17%. I think they may exagerate something (either shortness of hill or elevation gain). The Mt. Washington Auto Road Bike Race is generally regarded as the most wicked hill profile and theirs averages 12%. Regardless, I know this isn't a discussion about hill profiles very few us have ever ridden, so 12%, 15% or 17%, you'll be standing up on any bike you bring. Since you are asking, "Which bike?", I'd look at the triple and also take into account how much each one weighs.

B: OMG, totally did a double-take on the weakest thing I have every seen! Weak weak weak. Dude, Boulder, what happened to you?! I thought you were cool. I don't even know you anymore. Who imposes a speed restriction in a race? My apolgies to harmsz for this obvious threadjack, but that is ridiculous. I know it is for safety, but c'mon, is speed not the No. 1 goal of a race? If safety is a legit concern, then re-route and eliminate that hill. But OMG - 35mph? I hit that in city-limit sprints and crits. Talk about a banal speed. Scroll over to the elevation gain discussion and convert the kph that PoC mentions regarding Ironman Canada/Richter Pass and they far exceed 35mph. Next you'll see them put pace limits on the run so you don't over-exert yourself. "No one can attain a pace faster than 7:00 per mile." And what the hell are cops for? Unless the posted speed limit on the road (ie, for cars) is 35mph, they can't do anything! Are they going to write a ticket for exceeding the RD's lame speed limit if it is under the posted speed? Uhm, no.

Ok, rant over, time to salvage the post. Given the climb and that you have to slow down so you don't fall down and scwape your wittle knee, advantage: Road bike. If they didn't woos out and post a speed limit on the course (gag), I'd say take the tri bike because you could scream downhill. But since you'll be babysat riding the brakes the whole way down, take the bike that is easier to get up the hill.

It seems like they've opened a potential Pandora's box on this speed limit thing – regardless of how much of the course is covered. In a practical sense, 35mph downhill is the same as 35mph in a straight-away. (Just like a pound of feathers weighs as much as a pound of lead.) If the only concern is speed, then 35mph should be imposed over the entire 40k course. Rather, it seems the speed limit only pertains to a short section of downhill. (I’m not familiar with the course, but I’m envisioning a road down a hill/mountain with a gnarly drop-off). Obviously the concern is the speed plus the descent. While the resultant injuries from a crash may be more severe off of a hill than into a field, we do not know that. Just like you can drown in a bathtub, you can snap your neck at 35 into a cotton field in Lubbock. And if you ardently argue that downhill would be worse, then you are making my point for me: If it is the case that the downhill descent represents the danger, then the problem isn’t the speed - it is where the speed is attained.

It could be argued that if they knew the descent was dangerous enough to impose a cycling speed limit less than the posted auto speed limit, why are they using the road to begin with? A speed limit for the cyclists is an acknowledgment of the danger of the descent. Introducing a speed limit infers that riders will be "safe" at or below the speed limit. An analogy would be weight limits on pedals: Some superlight ti spindles are weight-rated up to 180lbs or so. As a rider, you expect to be safe on them up to 180lbs. If they brake at under 180lbs, there's a problem. So if you crash your bike at under 35, there's the same problem: like a manufacturer providing safety below a certain weight, the RD has stated (implicitly) that riders will be safe as long as they do not exceed a certain speed.

My point is that the speed limit should be whatever the posted auto speed limit is.* If a rider crashes and is injured above the posted speed limit, the RD has the legitimacy of the vehicular speed limit enforced by the Colorado Department of Transportation (or whomever comes up with speed limits, you get my point). The rider was exceeding the posted speed limit and is therefore responsible for his/her actions and outcomes. And in a larger sense it sets a questionable precedent to introduce the idea that bicycles somehow need different 'speed limits' than do cars, thus creating a 'special category' for bikes and eroding claims that bicycles are vehicles and are entitled to the same rights and responsibilities as cars.

*If the road speed limit is 35mph, then screw me, I've wasted 10-minutes of my life making a moot point.

Old Stage Road is kind of a residential street with a lot of driveways, I bet the speed limit is 30mph or max 35mph. It's not really windy at all, a few turns maybe. I assume that some one crashed really bad years back and now they have to enforce a speed limit to please whomever complained. To be honest, doesn't affect me much, my max speed is usually not much faster that 35... I know I'm a wimp!
Found this while searching for the speed limit: (must cut and paste in browser for some reason)
(www.dailycamera.com/news/2008/jun/24/injured-cyclist-watch-out-bears/)
Gotta love CO.

Here's the history on the speed limit:
http://m.dailycamera.com/news/2006/Jul/21/boulder-peak-triathlon-sets-bi...

So the rule came about because of 2 riders who, at different points in time, had accidents in the area and not necessarily during the race? Really? 1 accident because the rider crossed into oncoming traffic, another because the rider hit a ditch. Really?

I can understand safety concerns and it is only .6 miles, but... REALLY?