I’m thinking about getting a hatchet and wondering about rim/tyre combinations. It looks like in the same frame you could go either with 26 rim and 5” tyre, or 27.5 rim and 4” tyre. Has anyone ridden both combinations? Do they ride differently, or seem more or less the same?
The 27.5x4.0 is quite a recent size so you may get lucky to get a feedback from an early adopter.
However, the heart of the question is simpler: does the contact/volume can be noticeable between two similar diameters?
And the answer is yes.
Does one is better than the other?
It will depend on your riding style, terrain and preferences (what a surprise ).
I have been riding fat tires for most of my unicycling life. I also have experience with most of the common 26" tires now and I just got parts for my first 27.5 fat wheel. Reason for experimenting with fat tires is that most of my riding is either in snow, swamp or rooty/rocky singletrack. It’s also very flat here so weight is not a big issue.
My current favourite combination is 32 hole 80mm wide aluminium rim (40mm lightening holes between spokes) with 4.8 jumbo jim tire. This provides a low rolling resistance wheel that easily eats more than fist sized rocks without rider having to care about them. Jumbo jim also has good enough grip for summer but ice is horrible with it. My second favourite combination is my downhill/soft snow one. It has my last 125mm hub with 36 hole 110mm wide aluminium rim (without any extra holes) with snowshoe xxl tire. It is super grippy setup and dampens bigger bumps/jumps way better than jj (no “bounciness”). Problem for daily riding that I don’t like is that it has very high rolling resistance especially on harder surfaces.
Major difference with hatchet frame to my favourite setup is usage of 100mm hub. Now that I have ridden with it I won’t ever be building a wheel with 125mm hub again! Wide hubs cause unnecessary knee pain and less balanced spinning (when tired) for me and I don’t want that. Maximun rim width with regular frame design using 100mm hub is about 80mm. Only thing I’m missing from 125mm hub is wider rims.
So what would you like to know about how fat tires ride? As far as I know basically every fat tire rides differently and rim width has big effect on ride feel. What I’m looking for with my new wampa/gnarwhal combo is something agile that could compete with snowshoe xxl in snowy/icy conditions. With 27.5 rim you trade air volume for lightness. For outside diameter I think that snowshoe xxl is at least as big as gnarwhal 4.5.
If you have anything you would like to know more about don’t be afraid to ask. And I do use handmade steel frames with my fat tires. Also using similar “neck” structure to hatchet.
You have a point about the 125mm hub, that would be the main difference with a regular frame. Having said that, my 32" came with a 125mm hub, but it has straight cranks, as opposed to the high Q-factor I have on my KH 100mm hub. So all in all, I probably have about the same distance between the pedals.