If you are racing, why would you worry about brakes?

I raced 70.3 WC in Nice with rim brakes. It was completely fine. They do a great job marking the corners or slow-down sections on the road.

8,000 feet of descent, my friend.

Not as if millions of cyclists over the last 60 years have descended roads on rim brakes over the last 60 years. Wonder how we all did it before disc brakes were invented a few years ago ;-)

A more important question is: have you handled a road or TT bike going down a twisty 8% slope road 40-50 mph with some cross wind and around people? If the answer is no, you have a few things to work on before burning your money on a new bike. I would save that money to pay for a training camp in a location with these kind of roads and practice descending.

People were riding rim brakes for decades (and carbon rim brakes for a decade (?)), plus Nice course isn’t even close to super hard road conditions… It’s difficult. But it’s not super twisty, nor super steep, nor super long downhill, it’s mid-mountainous for European standards.

I bet, that if Iden was in Nice in September this year, he’d have been on his rim brake Giant tri bike and would’ve been close to winning the entire race.

So I wouldn’t dramatize. Would it be a catastrophe? No. Would it be a disadvantage? Probably, for most people. Could it be an advantage? Only for a few, considering lower weight and marginally better CdA.

For Nice course I’d choose disc brakes for another reason, though. It allows for a better tubeless setup, giving more comfort on those shit quality road fragments.

You will be fine...

I rode WC 70.3 Nice with rim brakes on 90/disc wheels on my TT bike.

However, I highly recommend you do not ride a TT bike. It is far better to race that course on a road bike with extensions. You will climb faster and descend faster.

With a textured braking surface like the NSW or HED jet blacks you will not have any disadvantage. Bear in mind that two years ago riders that podiumed in the tour de France chose rim over disc.