The Wheelsport Sunny is a more budget version compared to the Smart 1.0 wheelset, with a retail price that is usually $100 less than the Smart 1.0 wheelset. Let's see what are the differences!
Note that these observations are my own, and are not the official specifications made by Wheelsport. Especially since different generations or batches of wheelsets can have some differences, such as a slightly different hub or rim design. As discussed in the Wheelsport Rear Hub Maintenance Guide, hubs made in different years or for different OEM customers can have different specifications such as the type of rear hub used.
What I would highlight are the differences that can be seen from the outside, and also a bit about the rear hub design. The red wheelset shown below is the Wheelsport Sunny 451 wheelset from the Wheelsport Fantasy 2x10 speed mini velo, while the black Wheelsport Smart 1.0 451 wheelset is from the Wheelsport Fantasy 2x11 speed mini velo.
Ratchet design of the rear hubs, after the freehub body is removed. Both have similar rear hub ratchet designs.
Freehub body of the Wheelsport Sunny wheelset. 3 pawls with 3 individual springs.
Freehub body of the Wheelsport Smart 1.0 wheelset. 6 pawls with 1 large spring for all 6 pawls.
Are 3 pawls or 6 pawls better for a freehub design? It depends on what you want in your freehub.
Advantages of 6 pawls over 3 pawls:
1) In theory, twice as much engagement between ratchet and pawls
2) Less stress on each pawl, since the force is divided across 6 instead of 3 pawls
Advantages of 3 pawls over 6 pawls:
1) Less drag during freewheeling, as there are less pawls to compress during freewheeling
2) For the hub manufacturer, 3 pawls are cheaper to produce than 6
To the layman, 6 pawls may seem better as it will be stronger with more points of engagement. However during actual riding, it is unlikely that all 6 pawls will be fully engaged simultaneously due to manufacturing tolerances. In fact, if the ratchet and pawls are sufficiently strong, 1 or 2 pawls are already sufficient. 6 is actually overkill and can create more drag during freewheeling.
In this case, I actually prefer the 3 pawl design of the Wheelsport Sunny rear hub with 3 individual pawl springs. If one of the pawl springs break, there are still 2 more working pawls to support the load. Compared to the Wheelsport Smart 1.0 rear hub with 6 pawls and 1 spring, if the spring breaks, all 6 pawls will not function and the hub will not work. In terms of reliability, the 3 pawl design with 3 individual springs is actually more fail safe. In any case, pawl spring failure is rare and should not be something that you need to worry about.
These are the internal differences that will not matter to most riders, as they are not able to feel it during cycling anyway. The other difference is the freehub design.
For Wheelsport Sunny, it is only available in 10 speed freehub designs (correct as of end 2015). This means that if you want to install an 11 speed drivetrain, you cannot use the Wheelsport Sunny wheelset. Instead, you need to get the Wheelsport Smart 1.0 wheelset which comes with 11 speed compatible freehubs. 11 speed freehub bodies are 1.85mm longer than 8/9/10 speed freehub bodies.
Freehub body on the Wheelsport Smart 1.0 wheelset, with the 11 speed compatibility clearly labeled.
The other difference between Wheelsport Sunny and Smart 1.0 is the rim height. The Wheelsport Sunny has a low rim profile of around 19mm, while the Wheelsport Smart 1.0 has a 30mm rim profile. This difference is not obvious unless you put the two wheelsets side by side for comparison.
A higher profile rim is usually seen to be more aggressive and more aerodynamic, as seen by 50mm rim heights used by most road bikes. However, on small wheeled bikes, the speed is usually not fast enough to make a noticeable difference in aerodynamics. Also, a high profile rim can be more prone to side winds that will make the bike unstable, as experienced on the Dahon Boardwalk in Taiwan.
Another problem for higher profile rims is that the valve length of the inner tubes used need to be long enough, in order for sufficient protruding length for pumping the inner tubes. This is usually not a big issue, just something to take note of when buying inner tubes for high profile rims. Otherwise, you can always use a valve extender to extend the valve length.
19mm rim height on the Wheelsport Sunny rim on the left, 30mm rim height on the Wheelsport Smart 1.0 rim on the right. Also notice the different types of spokes used.
Lastly, the spokes used are also different. Wheelsport Sunny uses the more ordinary round spokes, while the Wheelsport Smart 1.0 uses the supposedly more aerodynamic bladed spokes. Bladed spokes on the Wheelsport Smart 1.0 look good and differentiates it from the lower cost Wheelsport Sunny.
The tire height also affects the overall rim profile. As seen below, a 406 sized Wheelsport Sunny with large Kojak tires has almost the same tire circumference as a 451 Wheelsport Smart 1.0 with low profile Schwalbe One tires.
A higher rim profile is usually also heavier in weight, as more material is used to produce the taller rim profile. In this case, if the same hub is used, the Wheelsport Sunny may actually be lighter than the more expensive Wheelsport Smart 1.0, given the different rim height. I am not able to give accurate numbers for the weight of the Wheelsport wheelsets, as they differ quite a bit from year to year. This variation is caused by the different rear hub used, different rim profile and different wheel size (406 or 451). The only accurate way to get the weight of the wheelset is to weigh the actual set that you are buying.
Similar overall tire circumference, despite the different rim size (406 vs 451) and different tires
1) Rear hub pawl design (3 vs 6 pawls)
2) Freehub body design (10 vs 11 speed)
3) Rim height (19mm vs 30mm)
4) Spokes (round vs bladed)
If you are going for a no frills wheelset that works well, the Wheelsport Sunny is an excellent choice at a very reasonable price. That is why I chose the Wheelsport Sunny wheelset when I built the Dahon MuEX, in order to hit a certain price point.
On the other hand, if you are going for the latest 11 speed drivetrain, or want a wheelset that looks more sporty with a slightly higher rim profile and bladed spokes, the Wheelsport Smart 1.0 does the job. Both are good wheelsets that are mainly differentiated by the features listed above.