The rear wheel (clincher, aluminium rim) is 234 grams heavier (1,171 instead of 928 grams) due to the measurement technology, so the complete set weighs 1,893 grams. Not a lightweight, but aerodynamically good. The "404" rolls particularly well in light winds diagonally from the front - ideal for "slow" time trials on long distances such as Trondheim-Oslo, where TOUR tester Manuel Jekel also used the bike.
It is less sensitive to side winds and runs very smoothly, which has not changed over the test distance. The stiffness drops from a weak 36 N/mm to an even weaker 33 N/mm due to the installation of the measuring hub. Obviously, the measuring axle is more bend-friendly than the original. These values are OK for time trials and training, but even light riders felt like they were pedalling in rubber when pedalling hard uphill. It was annoying that both test wheelsets showed damage to the left axle bearing after riding in the rain; the (replaceable) grooved ball bearings immediately started to rust. The power measurement functioned over the test distance without any dropouts or battery changes (you can do this yourself) and always delivered plausible values to the two available PowerTap handlebar computers, with which we combined the hub.
The simpler "Cervo" required new batteries after 3,000 kilometres. On a bumpy stretch of road, the computer jumped off the bike because the plastic holder spontaneously disintegrated. The computer survived the fall unscathed. On another occasion, however, a contact of the USB adapter disappeared in the housing and the computer could no longer be read out.
The larger "Joule 2.0" is read out directly via cable and plug connection and has a rechargeable battery with a running time of around 14 hours. It has enough memory for a year's training and a multi-line display that shows up to eight (three for Cervo) values simultaneously. The Joule has comprehensive analysis functions so that you can get a good overview of your training even without downloading the data and compare the current values with the best values of the year. This sets the Joule apart from other ANT+-compatible devices that can also communicate with the hub (e.g. from Garmin).
Mounted on the stem, Joule and Cervo sit a little close to the cyclist's nose. It would be better to place them in front of the handlebars.
The supplied "Power Agent" software provides a large amount of useful data, runs stably and is compatible with Windows, Mac and Linux. Only the display of the recorded intervals could be better.
ConclusionIn combination with Zipp's 404 wheels, the PowerTap hub is a good training tool in race trim with reliable wireless data recording. The weaknesses lie in the mechanical area. The poor bearing seal and the failure of the plastic parts on the Cervo computer are just as annoying as the incomprehensible operating instructions.
PLUSMeasurement system; aerodynamics; "Joule 2.0" computer; software; good concentricity
MINUSStiffness; seal hub bearing; weight; holder and USB adapter; "Cervo" computer
Reference/InfoSport Import, telephone 04405/9280-0, www.cycleops.com
Prices:
404 rear wheel with SL+ hub: 1,699 euros
Joule handlebar computer: 499 euros
Cervo handlebar computer: 239 euros
Photo: Markus Greber
