I am considering purchasing the Roval Fusee Star wheelset. I am curious if any of ST’s aero guru’s have any data on the aerodynamics of this wheelset. Specialized claims they are more aero than their original tri-spokes, yet they have not published any data.
Anyone ridden the wheels? Any comments on strength and stiffness would be appreciated.
Link to wheels:
http://www.specialized.com/bc/SBCEqProduct.jsp?spid=25345
Paul
Can someone explain this?
"Aerodynamically superior design yields 50% less frontal area, dramatically reduces wind drag "
What is the mechanism for reducing frontal area other than making it smaller?
I’ve seen the wheel… it really does have a very small frontal area. Although I don’t know what that 50% is in relation to (probably to a normal wheel).
I haven’t seen the data, but I suspect that the difference between their tri spoke and this new wheel might be small… hence they’d be willing to say that their new wheel is faster, but not willing to say by how much.
Making the frontal area smaller can be done by bringing the spokes much closer into the rim’s profile. If you’ve seen a tri spoke from the front, compared to a normal front wheel, you’ll realise that much of that difference in frontal area is due to the spokes of the normal front wheel.
Yes, the wheel has a smaller front profile. The design is similar in concept to the Spinergy Rev-X. The hub is very narrow. When you look at the wheel from the front, you only see a small amount of the hub flanges or spokes sticking out from behing the rim profile. It is my understanding that this is what made the Rev-X aero, and seems likely would make this an aero wheelset as well.
This is in contrast to the deep rim with standard hub approach. In that case the wheel still has its widest point at the hub flanges, but a much longer portion of the spokes hide behind the rim as compared to a standard box rim. It is my understanding that the primary aero advantage of the deep rim is NOT the rim shape, but the fact that less length of the spoke extends outside of the rim profile. (Note I said primary advantage is hiding the spokes behind the rim. I am sure the rim shape can be a contributor.)
I was hoping some of the guys with tunnel data (Josh at Zipp?) might have some data here? I am thinking of replacing an old set of Rev-X’s (which I love) with some new wheels. I have really like the old Rev-X’s, but they have seen serious use and are showing signs of wear. So my main point is to not downgrade from an aero stand perspective.
But it just dawned on me, if no one from Zipp speaks up, then these wheels must be the FASTEST!!! 
Paul
I rode on a pair and liked them, however they werent particularily(sp?) lite for the cost, I also wondered about replacing spokes on them.
Interesting perspective. I can follow the logic of the narrower hub and the spokes being hidden more behind the wheel. However, each spoke individually is what, 1/8th of an inch at most. There’s a whole lot of empty space between the spokes even with a 32 spoke wheel. 50% is a pretty incredible claim, now I’m interested in seeing some in person. I can see where they may have reduced the width by 50%, but not the frontal area.
True, they are not light at 1750 grams. But I am really not concerned about weight. (I actually race on a steel Ritchey Breakaway cyclocross bike; probably about 22 pounds “race ready”.)
Paul
I have not done any testing on these particular wheels, we tried to get a pair for our last tunnel test and could not get them in time…
I will say that we have done lots of testing on different hub flange widths from very narrow to as wide as you can fit between the fork blades and I can tell you that there is very little to no difference between them when built using the same rims and spokes. Remember that the frontal area is only reduced at 0 degrees wind angle, which is a very, very rare occurence in the real world, so most wind angles in the real world will be between 10 and 20 degrees, so the frontal area at zero is really not the key issue in the real world. My understanding was that they were saying the flanges themselves were aerodynamically profiled and adds surface area to the wheel to add aero advantage in cross winds, but I’m not sure and at this point have no data either way. I give them a lot of credit for trying something new, and it has a great look that is very distinct to the brand, I really loved the way they blew up the image of the red flange on the disc wheel of that TT prototype.
Having said that, we really feel that rim shape and depth are the two key factors to improved aero and have done hundreds of hours of wind tunnel testing on refinements in these direction with very good results. For a long time everybody, us included believed that deep rims were effective because they reduced spoke length and allowed for lower spoke counts, plus they provide added surface area for cross wind performance, but in the last 7 or 8 years we have seen that rim shapes can make very, very big differences. The recent Velomotion wind tunnel test in germany (won by the 808) is a good example where a wheel with a 25mm rim finished next to last and the last place wheel used a 50mm carbon rim and the difference was significant, so depth isn’t everything.
Josh,
Thanks for taking the time to respond; you are a great resource here on ST.
I was still on the old model, where I “believed that deep rims were effective because they reduced spoke length and allowed for lower spoke counts, plus they provide added surface area for cross wind performance”.
So thanks for letting me know that the current thinking is that there is benefit to rim shape, and less to hub flange width.
Having seen and held the Roval’s, I can say that there is nothing that looks aero about the star flange. It is basically just a flat piece of aluminum. So it may provide some cross sectional area, but not much.
If you do test these wheels, please let us know the results
Thanks again,
Paul
I thought it was interesting that the Gerolsteiner team did not use them at the Tour of Italy TTT yesterday. Here’s a shot of their front wheels:
Giro Photo from Cyclingnews
They used disks in back.
-Marc
The Giro TTT was a very rolly course, they went for something lighter that accelerated faster for the course. That said, looking back at the pics, it looks like Lampre/Fondital may have been running the Rovals.
Here’s a photo of Lampre in action— Definitely not the Fusee Stars:
Looks like they are using the straight Tarmac road frames with a rear disk and a lightweight aluminum front wheel.
-Marc
Yeah, I wasn’t sure, the shots I saw were from head-on, and the red spokes threw me off.
Alot of teams rode road bikes, some with an aero cockpit, others, a standard drop bar.
I actually rode with someone last summer and he was on a set of these wheels. I asked him about them with regard to aerodynamics and all that and his response was “Not aero at all, but they look cool.” From what I saw it’s a really shallow rim with a starfish kebob in the middle. No idea what the point is really, though I am sure someone at SPecialized has one.