In spite of these differences, should your wheel size factor into winter riding? I think there are more important things to worry about. Wheel size will not impact your winter riding experience nearly as much as other fat bike components.
Unless you are worried about summer performance, I wouldn’t think too hard between 26 and 27.5. The only exception is if you want a super wide tire with extra float, which I’ll discuss below.
If you find the perfect fat bike—dropper, good brakes, geo you like but the wheels are 26, just buy it. For winter fat biking I would not let the wheel size determine your bike choice. There are advantages to each size, but not enough to make it the basis of your decision.
There are more important factors to consider, like how the bike feels, whether it has a dropper, if it has a lighter carbon fork, if the drivetrain is reliable, etc.
The two exceptions to this are if you plan on using the bike in summer and if you have consistently snowy conditions and/ or your trails aren’t regularly groomed or packed down by snowshoers.
If you plan on riding in summer, 27.5 wheels will be noticeably faster, roll obstacles easier, and be less sluggish than 26 wheels with wide tires. An important caveat is tire width. I would not go less than 4.5” for winter fat biking. Some fat bikes come with narrower (4”) 27.5 tires and I would not consider them unless your trails are always hard packed.
If you commonly experience powder conditions, having super wide 26 tires (greater than 4.5”, up to 5” for some frames) provide extra float keeping you on top of the snow.
For the majority of winter fat biking conditions, where trails are regularly packed down or groomed, wheel size should be near the bottom of your list of fat bike considerations. Other factors will have a bigger impact on your winter ride quality.
Interesting read, but if you are going to compare things like speed between wheel sizes you need to run the same tires in each size. Otherwise there is no valuable information you can use. Tread pattern, compound and width make such a big difference
If you plan to ride in the snow, then 26 is by far the way to go simply because of how much more volume there is as tires get wider. A 26×5 tire has about 20% more volume than a 27.5×4.5. That is a very noticeable performance difference especially if you dare to ride something more adventurous than manicured groomed trails. A 26×4.8 has about 10% more volume and even a 26×4.6 has slightly more volume than a 27.5×4.5.
Those are all great points, thanks for the input Joshua! I aim to provide readers with as much background about my experience, so they can take what they need from my articles. Having other readers fill in the blind spots with their information is a help to everyone. Thanks for taking the time to reply!