Bike Forums - New Firecrest 303s

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I am more of a fan of the 202's. So I was hoping Zipp would update those along the same way they did the 303's. They built up the new 202's with the new hubs (ZR1) made the rim shallower, and still managed to maintain the same weight and price as the previous version of the 202 Firecrest (no hookless rims). I guess it's pretty obvious which demographic Zipp is targeting. So disappointed :(

That being said, it doesn't mean if, by some miracle, I had a couple grand burning a hole in my pocket I wouldn't buy the new 303's :)

Quote:

Originally Posted by Seattle Forrest (Post 21505640)

Does it matter if the rim is shallower if it's faster? That just means less weight, and less vulnerability to cross winds, right?

But that design choice [hookless] has allowed this wheel to become more efficient overall. It has a more bulbous rim profile that allows the tire to sit wider, meaning less tire deflection, a shorter contact patch and reduced rolling resistance. Energy lost to vibrations in the road has also decreased thanks to higher volume tires running at lower pressures.

Yeah, i read that. I get the argument about lower pressures/wider tyres etc but honestly, i am still a bit dubious.

I buy that there are a lot of times where a wider, lower pressure tire will be faster. Except for the deep sections on my TT bike (which are still moderately wide), all my wheels are 21-23mm ID, 28-30mm OD. I just dont know far you can keep extrapolating this. Wheels designed for road and gravel - sure, 30-32c may be the fastest. But wheels designed for going fast on smooth tarmac? Eg, Specialized's fastest wheels, the Roval CLX64s, were optimized with their 24c Turbo Cottons (which measure 27.xx when mounted on the rim).

Anyway, I am not really disagreeing with you - just some stream of consciousness rambling that came to mind during this discussion.

It's not just RR that makes them wider. The giant internal width and lack of brake track mean the tire/rim interface involves less turbulence.

I agree you can't just make tires as big as a steamroller and hope to go faster because of it. Personally I feel like 28 mm is the sweet spot for road. I put in more than a decade on 23s, and I'm faster now. It's not exactly a fair comparison going from box section rims to (wide) Enves, a standard to compact, and a new decade in life.