First, nobody sold me on these tires. I picked them out after a lot of research. I've been driving for 47 years, had a business for 21 years with a small fleet of vehicles, trailers, and equipment, managed a similar fleet and field operations for 8 years prior to that, and grew up wrenching everything I owned. So there's my ZERO technical tire and automotive skills. It's sad how people make assumptions rather than just ask a friendly question.
Your claim that 205/65/15 tires are the complete wrong tire for the NV200 are merely your opinion and probably should have been stated as such along with the reasoning regarding your opinion. Application and location do play a large role in tire selection.
As I listed in my original post, this is an experiment. No I didn't choose the 205/60/15 Russian made Nokians you suggest. I chose a Chinese brand manufactured in Thailand and for good reason. This is an EXPERIMENT ! They have a 40,000 mile warranty, and I could put 2 complete sets on to 1 set of a name brand tire, although this is not my intention. Someone else may have to opt for a cheap set so I'll have information available down the road for those people.
I'm not operating a maxed out GVWR unevenly loaded NV200 in Canada. I'm in Florida, run 500-700lb loads with 80/20% cruising/city driving so, big difference in both application and location. One thing for sure, I will never again run any kind of 185/60/15 tires on my NV200.
The 205/65/15 tires have a sidewall that is nearly an inch taller, hence a meatier sidewall and nearly an inch more ground clearance.They are about 3/4" wider (same as your Nokians) - no issues there. They are about 1 3/4" taller. So simple math takes care of the speedo/odom differences. The 7.38% greater tire circumference does changes the final drive ratio and probably wouldn't be a good choice for those running a max load on a daily basis. There seems to be no computer issues regarding tire size change either.
My findings so far: I really like the new tires after about 1,400 miles of driving. There is a slight reduction in acceleration based on my application but not enough to make it scary trying to merge in traffic or whatnot. My mpg has gone from 25+ to 26+ mpg. This is a 3 full tank average using math, not the vehicle computations. Braking is fine and even these cheap 4 ply tires (2-siewall plies) not not feel mushy in cornering. Driving in the Florida rains feels a little safer. The ride is great and feels like a completely different (better) vehicle.
Am I recommending that everyone replace their NV200 tires with the 205/65/15 size. Absolutely not!! The jury is still out. I am hoping these will work out for light to mid load carriers as there are a lot of brand options in this size with load ranges from 92 to 102 and many snow tires as well. Again, this is an experiment and I posted to let others know what I'm doing. There is also another reason I'll get into in an update down the road which I will do regardless of the semi-condescending posts of others.