After returning the Profile Design Altair wheelset that I had while my bearings were being replaced. Shortly after I returned that wheelset, I started to miss having the aero wheels. Do they make that big of a difference? Yes, they do. From some of the data I have seen, aero wheels save you approximately 20-25 watts over standard rims. So, luckily, I was able to get my hands on another aero wheelset, the Grammo Viper 50C wheels.
The Grammo Viper 50C wheels are a full carbon rim that is 50mm deep. The hubs are from American Classic and roll really smooth. There are plenty of engagement points on the rear hub, ensuring that everytime you pedal, you are getting poewr to the wheel. The Grammo brand seems to be a budget brand, compared to others. It seems as if the Viper 50C may have been discontinued, but their tubular version is online at $650. Grammo does have a newer, deeper wheel, the Grammo 580, but it includes an aluminum braking surface and adds 270g and retails at $985. So, similar in weight and size to the profile altairs, but retails for almost $600 less than the profile design altair 52 semi carbon.
The Grammo Viper 50C wheels had some big improvements over the Profile Design Altair 52 semi carbon wheelset. The Grammo aero wheelset came in at 1520g for the set without sewers. This made the biggest difference between the wheels. The Grammo wheels would accelerate much faster. They also climbed very well compared to the Profile Design wheels, while still have the same speed on the flats and decents. However, the wind seemed to afect the Grammo aero wheelset a bit more than it did the profile wheels. I think this is largely due to the weight.
Another difference I noticed was that the Grammo wheels were much wider than the Profile Design, or even my Mavic wheels. I had to adjust my brake cables to get the rims to fit inside the calipers.
Lastly, with the Grammo wheels being a full carbon wheelset, they made a lot of noise. This could be a negative thing because it might worry most people, feeling like the rims could fail at any moment. However, that is just the way the hollow carbon rims emit sound.
All three wheelsets that I have used (Profile Design Altair 52 Semi Carbon, Mavic Kysrium SL, and Grammo Viper 50C), I’d choose the Grammo Viper 50C. It had na slight weight penalty over the mavics, but I feel as if reduction in drag, even while climbing, causes less of a power requirement to overcome. They are stiff enough for my sprints, they are fast on the flats, and they do decent enough in a crosswind. Now, I just have to try and figure out why they discontinued these wheels and stopped offering a full carbon rim.