Lets talk a bit about bigger wheels. Bigger fat bike wheels. This year Trek has come out with a 27.5 inch wheel. In the past I have scoffed at the mountain bike 27.5 and now I have to explain myself when I now say its great for the fat bike. First off, Im all for bigger wheels. I was on 29in MTB wheels for years. Pretty much since they started coming on high end bikes. My first 29er was a Trek Superfly in 2010 and I never looked back. The bigger wheels just rolled better over stuff. And when I was still racing, would hold momentum longer. Being a bigger guy I lived and died by momentum. I struggled with the ups, and needed to take full advantage of the downs. And the bigger hoops did that.
After a few years, the high end cross country rigs pretty much only came with 29in wheels. Overall, they were just faster. Sure, the knock on then was weight since it’s a bigger wheel and bigger tire they weighed more than a 26in at the time. So climbing might have taken a small hit. Also the acceleration was a bit slower than a 26in wheel. Again, the weight thing. Turning was not as crisp with a taller wheel too. But all the major brands did all the testing and it was the 29in wheel that came out as the all around faster wheel on a MTB. And the bigger wheel being faster was established years ago by many brands. As far as Im concerned, the 27.5in MTB wheel is just for those who still don’t believe it. And for some trail bikes that generally go downhill more than up.
So enter 2016 and Treks Farley. Three models coming with 27.5in wheels with 3.7in tires. The 9.8, the one I ride, coming in carbon wheels, the other models coming in aluminum wheels.
So, it makes the same sense as MTB’s to go bigger with the fat bikes right? That would be correct. But all those MTB bigger hoop scenarios pretty much come into play in the summer. You see fat bikes, at least the high end ones, are made to be ripped in the summer as well as the winter. So thats a given. Bigger hoops in the summer has the same advantages as MTB’s when they went to bigger wheels.
However, we ride these in the snow too. I mean, aren’t they made specifically for the snow and winter. Even tho I ride them year round I will say yes, that’s really why they are here.
So when you’re tooling around in the snow what’s the advantage to a 27.5 vs a 26 wheel? I mean besides the summer advantages of a better roll? First off let’s compare size.
A 26 by 5in wheel is pretty close to a 27.5 by 4 in outside diameter. The 26in is a little bigger but not by much. So really, no real advantage to the roll. Maybe a little. 26 by big tire is pretty close to 27.5 with a smaller tire. But let’s compare apples to apples. Lets look at a 26 by 4 to a 27.5 by 4.
When you’re talking fat bike in the snow the real difference is the footprint. Obviously a bigger footprint gives you more float. No one knows that better than I do being a bigger guy. So when riding some super cool groomed trail here’s the deal.
If you look at a the footprint of a 26 by 4 you get sort of a square. When you look at the foot print of a 27.5 by 4 you get more of a rectangle. The bigger hoop has a longer print and thusly more float. And when racing on a groomed or semi groomed trail thinner is faster. Or at least less resistance. You can get a wider print using a 26 by 5 wheel\tire. But when riding groomed it’s more to push. A longer thinner footprint is faster than a wider shorter one.
A regular dude like me will not be as affected by the wheels size as a faster rider. While Im retired from racing competitively Ive been riding these wheels ongoing since Sept of last year. I do notice the effects of a bigger hoop just like I did when I went to a 29er. It just rolls really fast. I can get near the same float with a 27.5 by 4 as a 26 by 5 and run a thinner tire. And if you’re into racing events like the Birkie this wheel size is a plus. But if you’re a regular schmuck like me it works just fine too.
This wheel size is new. There is only one tire to use. Im sure in time this will take off like the 29er did. It just need to settle in. You don’t see or hear of a lot of words on this wheel size since it is so new but trust me, all the big guns are working on it as I type.
Always looking a new stuff. Here is a stock carbon 80mil Wampa 27.5 on Treks Hodag. and along side is the same 27.5 Hodag tire on a 45mil WTB Scraper wheel. About the same diameter but much thinner. This would be considered a summer setup but Im running this on my new Farley build to finish out the winter. Pretty skinny fat bike wheels and I hope I don’t get in too much trouble with that. I’ll have these wheels at the Birkie in March and if its soft I might be regretting it. Or, it can be hard as concrete and I will be ripping it up.
I’ll hope for the latter…