[xDownSetx]

Could be in anticipation of strom riders who take the bike off-road and who will be moving at a much slower pace for extended periods.

 

[bower100]

I assume you don't have them side by side to compare so maybe the SV ones simply a tad wider.
What the previous fella said might be right but really, there's more science to it than just the physical size, tubes diameters and so how flow capacity is affected. The amount of finning between the tubes and the spacing of the passages between the finning affects performance.
I have a Husqvarna 4 stroke dirtbike. I've replaced the radiators, (smashed the origionals),and I learned Husky sources them from 3 different manufacturers. The replacements I got, while the same physical size, had two less tubes. But as a result of that they also had more space between the tubes and so more finning.
Nothing changed about the cooling requirements of the bike, just two different methods of acheiving it.

Dave

 

[Boit4852]

When it comes to these questions, I have to stop and think about my education....specifically physics. I'm old, but if I remember correctly, cooling efficiency/capacity is affected by a few factors. Efficiency may or may NOT be directly affected by capacity. Motorcycle manufacturers are looking to shave weight so capacity is quickly sacrificed. Now, how to increase efficiency with lower weight/capacity? Well, add surface area and decrease tube thickness while maintaining air flow across the cooling tubes. Still, reliability must also be protected. How about pressure? Gotta keep an eye on that part of the overall design. Aluminum? Stainless? Titanium? BTU transfer efficiency? Coolant selection? Etc. Geez, my head spins!