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26 vs. 27.5 Fat Bike Wheels

Mi amigo Blatz, pinged me the other day with a question. He’s working out the build plan on a new fatty and he asked “Are 26 inch Fat bike wheels going the way of the Doo Doo bird ?” It’s a pretty common inquiry for anyone that’s N+1. I’ve been test-riding 27.5 fat bike wheels side by side with 26-inch fat bike wheels since the spring of 2018.

Some of the wheels that we have in play this winter

My theory on fat-bike wheels is based on a fat-bike consisting of two or three $2500 chunks. Those chunks consist of one frame and fork and two sets of wheels. The point that I’m clumsily trying to explain is that wheels are every bit as important of an investment as the frame/fork/components. A wheelset can significantly influence how a bike rides so it’s no wonder that people want to make the right choice on their maximum flotation set of wheels.

The first question that you have to ask yourself is, “Do I need Maximum Floatation?” If you weigh over 230 lbs. or you ride ungroomed deep soft snow or sand the answer is probably yes. If you weigh less than 200 lbs. and you only ride groomed snow the answer is probably no.

In the 26″ fat-bike world, maximum flotation is achieved with 4.8 – 5.05 inch tires mounted on 100mm rims. Most 26″ fat bikes have 80mm wide rims and they’re great for most people. Riders looking for maximum flotation would need two sets of fat-bike wheels to cover the full gamut from groomed to soft conditions fat-bike fun. In the 27.5 fat-bike world maximum flotation isn’t achieved with a wider rim. 27.5 max-float is achieved with a larger tire. So instead of needing to have two sets of fat-bike wheels, you have the option to build a second set of 27.5 or 29 wheels for firmer/faster surfaces, thus expanding the role of your omni-terrain fat-bike.

From where I stand, the max flotation comparison is a wash. Primarily because I ride a set of 100mm wide, feather-light HED 26″ wheels with Johnny 5’s for max float. If you don’t have a set of 100’s you might give a slight advantage to 27.5. 27.5 max flotation setups stand ~80mm taller than 26-max. When I’m riding on the back of a greased pig (ungroomed snow) I’d rather have my center of gravity 80mm lower. The bottom line is – if you ride a fatty with 26″ wheels, you don’t need to feel like you’re missing out on some huge improvement. IMHO going tubeless or upgrading to lighter wheels is a much better way to achieve a better ride experience than switching over to 27.5.

The other factor that comes into play between the two-wheel diameters is tire availability. We’re currently in a temporary supply chain delay that makes finding tires (26 or 27.5) that you can actually purchase much more of a challenge. Not every tire maker has embraced the production of 27.5 tires. There’s no 27.5 version of Bud & Lou and no 27.5 Schwalbe Jumbo Jims. So there’s a short-term advantage to 26″ wheels in that category but if I were to look past the current supply chain event into 2023-25 that balance of power might shift towards 27.5 as companies lean further into the evolution towards that wheel diameter.

Should your next bike have 27.5″ Wheels? I’m afraid that you may not have much of a choice. Do you need to run out and trade your old 26″ fatty for a newer model? Focusing on the key word ‘need’ I’d say probably not. I also think that it’s ok if that’s what you want to do with your bike allowance. To be completely honest, I haven’t experienced anything from the 27.5 fat platform that makes upgrading from 26″ something to champion.

Here’s an interesting factoid – Corey Stelljes has won back to back Fat-Bike Birkies on a set of 26″ HED carbon wheels on tires that aren’t available in 27.5. So put that in your pipe and smoke it!

The other side of the coin is that there’s also nothing wrong with fat-bikes that have 27.5″ wheels. The downside that still exists is the limited availability of 27.5 tires. When the industry rebounds from the current supply chain issues that situation is likely to change. For many legacy fat-bikes, the 27.5 x 4.5 max flotation setup will not fit in the rear triangle (with some exceptions). A majority of legacy fatties are able to run 27.5 x 4 setups (with some major exceptions like older Beargreases).

I’ve tried to explain the subtle differences that exist between 26″ and 27.5″ fat bike wheels. There’s virtually no quantifiable difference between 26×4 and 27.5 x 4. The differences mainly exist when you look at achieving maximum flotation and are slightly exacerbated by the limited availability of 27.5 tires. (no Bud & Lou). In my final analysis, I would call it a tie ball game. If you love your 26″ wheeled fat-bike, keep riding it like you stole it. If you want to buy a new bike and it comes with 27.5″ wheels…go in knowing that your favorite tread patterns might not be available and that you might have to live with the tires that come with the new bike for a while. Just don’t expect to feel a huge uptick in the performance of your new steed from the new wheel size. #sameasiteverwas

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8 Responses to 26 vs. 27.5 Fat Bike Wheels

  1. Allroy March 1, 2021 at 2:30 pm #

    Thanks for the info. I have been questioning the need for yet another standard. I am pretty tall ,so a lower centre of gravity makes a bit more sense. Definitely appreciate the comparison write up 👍

  2. Rob March 10, 2021 at 3:41 pm #

    I’ve been ignoring 27.5s because I’m too cheap to buy another new bike. Thanks to this article, I can continue to ignore the until I truly need a new bike.

  3. Timmy Grimme March 12, 2021 at 10:35 am #

    Strong second on max float with bud&lou.

    What about 27.5 X 3 versus 29 X 3 plussy comparison?

    I’ve had some fun recently on a 27.5 karate monkey and am considering a 27.5 wheel set for my ICT.

    • Gomez March 14, 2021 at 7:43 am #

      27.5 plus rims with 3.8’s work really well, but 27.5 plus rims with plus tires lowered the bb enough that I would get pedal strikes on my fat-bike. 29’r is the way to go for your ICT wheelset.

  4. AA March 16, 2021 at 1:29 pm #

    So this begs the question: Is there an “appreciable” difference between 80 rims and 100 rims for flotation?

    • Gomez March 16, 2021 at 3:00 pm #

      4.2
      4.2″ Wrathlorde on 80mm rim vs 4.8″ Johnny 5 on 100mm rim

      • Erv Spanks March 16, 2021 at 10:21 pm #

        Nice plate👍

  5. Greg September 28, 2021 at 9:13 am #

    Where can I find a set of 27.5/3.8? I have a tag bike but mine are wore out.

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