In this article I’m reflecting on my experience riding both 26 and 27.5 fat bike wheels. This is not a technical article, I’m just discussing the main points in case you’re trying to decide between the two.
The bottom line–although there are mild differences in performance, I would not let wheel size define a fat bike purchase.
However, if you do plan on riding your fat bike in summer or dry conditions are common on your trails in winter, I would lean toward 27.5.
26 v 27.5 Fat Bike Wheels
My Fat Bike Wheel Experience
Most of my fat biking is on the Eastern slopes of the Rockies near Calgary. We typically have snow coverage for all of winter, although the odd chinook occasionally returns trails to summer conditions. They also cause freeze thaw cycles which result in icy sections.
For tires, I rode the 26 4.7” Bontrager Barbegazis for 3 seasons. They were a great tire and in spite of their low lug profile they had plenty of grip. These came stock on my old Trek Farley 7 with 26 wheels.
My current tires are 27 4.5 Bontrager Gnarwhals, which came stock on my 2021 Trek Farley 5. They have much larger lugs than the Barbegazis and I find them to be much better performing than the 26 Barbegazis. The difference in tread profile between these two tires does hinder a direct wheel size comparison, but here’s what I’ve found.
How 26 Compares to 27.5 Fat Bike Wheels
I can say with absolute certainty that 27.5 are noticeably faster than 26, even in slow snowy conditions, at similar pressures.
I sold my old Trek Farley 7, with the 26 4.7” Barbegazis, to a friend. We have a similar weight yet my 27.5 wheels carry more speed for longer. This is in spite of the bigger lugs and less float of my Gnarwhal tires.
The 27.5 tires also have noticeably better grip. No doubt much of this is due to the more aggressive lugs, but the footprint of the 27.5 feels noticeably larger as well. Technically, a wider wheel will always have a larger contact patch (assuming similar tire width), but when I first bought the 2021 Farley 5 I had my doubts as to how much of a difference it would make.
But, if I had 26 tires that were wider than 4.7”, maybe the contact patch would feel closer to 27 4.5” tires.
I have no doubt that if I rode my fat bike in summer conditions, with higher pressures, these differences would be even greater. The 27.5 would roll over obstacles easier and be even quicker in dry conditions.
Should Fat Bike Wheel Size Factor Into Your Decision
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.
26 v 27.5 Fat Bike Wheels Summary
It seems every year there’s a new bike standard. Now many fat bikes come with 27.5, some with 26, and some will accommodate both sizes.
Unless you experience persistent powder conditions or plan on riding year-round in dry conditions, wheel size should not be a make-or-break consideration. Since fat biking is much slower than summer with far less traction, other factors like bike fit and dropper posts will have a greater impact to your ride quality than wheel size.
If you disagree, or have something to add from your experience, comment below!
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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!