Zipp 404 build questions + Corima Viva/Aero vs 202/303

[djaeggi]

Hello,

Long time lurker, first post here and hope you can help me with some wheelset choices.

Background. I have 3 wheelsets I use for racing (TTs and road races, both crits and longer 2-3hr race). These are:

HED Ardennes clinchers - great wheels, and I use these in races when the weather is filthy or for sunday best/sportives.
Mavic CXP30 tubs - very old school set, these were my first tubulars and were built up on a budget.
Planet X/Gigantex 50mm carbon tubs - a good few years old now, these are narrow and have a v profile.

Basically, I'm looking to upgrade the CXP30 and 50mm wheelsets. I don't use the CXP30s too much - they're neither aero nor lightweight, their only advantage is that they're ultra-bombproof, but at 70kg I don't have an issue with putting wheels out of true. The 50mm wheels... On the one hand, on flat courses or when the wind is light, I'd like something faster/deeper sectioned. When things are hillier and windy, I'd like something lighter and less sensitive to crosswinds. So, the thought is to replace both wheelsets, and get something with 60mm deep rim and something lightweight with a 30-40mm section.

Budget's an issue here, both in terms out outright cost as well as "value at risk" i.e. I don't want to be worrying about how I'm going to pay for a new wheelset when I crash! Similarly I'd like to end up with 2 decent wheelsets, both so I have options, also so I have a set in reserve if something happens to the other one. I'm basically looking at secondhand, or buying rims and building myself (all these wheels I've built myself and am happy to keep doing so).

Zipp 404s
A friend has a pair of 2010 Zipp 404s that he's looking to offload. The front is ready to go, the rear 24h needs rebuilding (it was on a powertap). These seems ideal, as it's a relatively budget way to get a decent set of deep sections, and these will certainly meet my criteria. Questions are:

1. These are old shape, i.e. pre-Firecrest. Is there much tangible/real-world difference in their performance, either from a durability/stiffness point of view or aero, particularly cross-wind sensitivity? I.e. is it worth holding out for a secondhand set of 404 Firecrests? Price wise these are compelling.

2. Looking at a rear-wheel build, I see that Zipp have 100N as the max tension. This is low and, given the potential for very low NDS tension with some hubs, should I be thinking carefully about hub choice here? I'm thinking something like a DT 240, with relatively narrow flanges, should do well here. Any practical experience building up 404 rims welcome, just want to check I don't bite off more than I can chew building these up!

Corima Viva/Zipp 202
For the second set of wheels, I can get Corima rims relatively cheaply, and I can recycle the hubset from my 50mm to build these up. The Vivas should build into a 1100g wheelset, which is super light and appealing for hilly road races! Question though, the Corima rim profiles seem quite old-fashioned... compared to something like a zipp 202 (which weight something similar) am I shooting myself in the foot a little with regards aero performance? Or should I be ignoring these relatively shallow wheelsets and looking at the Corima Aero+/Zipp 303 and get more of an aero benefit for only a slight increase in weight? Any direct comparison of the Aero+ with a 303 would be welcome, again I worry that the Corimas might have relatively poor aero performance. I'm basically after an aero wheelset that I can take out on a properly windy day and not worry about being caught in crosswinds, or take to hilly events.

Thanks for any input!

[djaeggi]

No-one?! I'm taking on the 404s in any case; any tips appreciated otherwise I'll use my common sense and engineering judgement as regards the build!

Separately, been looking seriously the Reynolds Aero range, and the 46 might just take the biscuit for a shallower/lighter set, plus these are priced very well. Any comments on these welcome too!

[mdusink]

I have no experience with the wheels your looking at, but I do have them on my radar for myself. I ride a wheelset with belgium rims and one with 35mm carbon rims. Both build up myself. Your primairy concern is aero on the shallow rims. If I look at the data from serveral sites, aeroness really start to matter at the 60mm rims and higher, and even then it's a couple of watts. An good fitting shirt, an aero helmet, good training + recovery and a professional bike fit will deliver you more then the gains of the corima vs 202 wheelset.

To conclude, the 404 should deliver what you want in aeroness. 202 vs corima shouldn't matter. If you still need a choice, the corima's are ridden in the propeloton. The 202 not anymore I believe (altough I'm gladly corrected)