How fat is too fat

I am interested in a fattie. Reading about them makes me want to add one to my growing fleet (hello Jacob where ever you are) sooner then later.

I’m curious what the downside is to a fat tire (off road of course) and when is a fattie fat enough? I see fat tire reviews for tires ranging from 3 to 5 inches. Is there a point of dimishing returns concerning tire size?

Still not too Fat.


Fat tires are like any other tires, the bigger they are the more cushion they provide but at the cost of an extra drag (more contact to the ground).

And because of their size, they are more sensitive to the tire pressure: if you are too low, you will get a sluggish auto-steering uni. And if you are too high, you will get a paddle boat :smiley:

You have to keep in mind that these are tires designed for a specific purpose in mind: floatation situations (snow, mud, sand). Other situations will involve trade offs and will depend on your riding style and adaptability.

Out of my own experience, I tried a couple of 1st generation fat tires and they were difficult to ride. However, I am now riding a Surly Lou 120tpi and it is a pleasure to ride at 15psi (I am 145 lbs) as the casing provide enough absorption. But the same tire at 5psi on hardpack will feel like a tank. The same goes for your crank choice (you need to keep it rolling…).

If you feel like your 3.0 tire is too small to be comfy or you can meet a fmuni rider (that’s a thing… :stuck_out_tongue: ) for a test ride, give it a go. Keep in mind that it is not for everybody and even a nice setup will take a small adjustment phase (my first ride felt like I really must make it turn… and now it feels like any other uni :slight_smile: ).

if a ride with a 24x3 (140mm cranks) and meet an unexpected rock on my trail I can zigzag around it.
with a 26x4 (Hüsker Dü + 160mm cranks) I am obliged to go over it ! (because zigzaguing at the last second is near to impossible)

Keep in mind that the wheel plays a role in determining the overall width as well. I regularly ride with a friend who has basically the same uni as me (KH24, with Duro Wildlife Leopard tire), except he has a Large Marge rim on his. I don’t know what the exact width measurement is, but side-by-side with my standard KH rim, his is noticeably wider.

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Whaaat :astonished: I don’t believe it. He’s wearing a number so is he competing?

Great photo. I’d love to know the history of this event.

Also, does a fatty ride better with no tyre thread?

This photo is from the Facebook Unicycle Chat page. Taken last weekend at a cyclocross race in Anchorage, Alaska. Rider is Benjamin Richardson, builder is Curtis (last name not given). Built from an old Super Cub (airplane) tundra wheel and custom frame.

Here’s another shot, showing the frame a little better. (No word on how the thing actually rides, but I’m guessing “it takes a little getting used to.”)

fat uni in Anchorage.jpg

Thanks for the photos and the info, Lance

That’s awesome.

Hey Killian, have you seen this monster. :p:p

Literallly lolled at that. :slight_smile: Thanks for posting the pic!

I have a Triple Triton with a 26x3.8 120 TPI Surly Nate that you can try if we can meet up sometime. I’m curious about the 5" tires but that’s about as wide as that frame will go. Wider tires also mean greater diameter which in addition to the heaviness add to the challenge on inclines. With my tire I can ride in deep sand but go very slow and I imagine a wider tire would let me go faster. My frame already has some knee clearance issues but Jakob’s frames are better in that regard.

Southwest Airlines has a specific answer to that question… :stuck_out_tongue:

That’s a great, bouncy-looking uni! Here’s a silly fattie I got to try out at Unicon XVI in Italy.

I ride Mister Fatty in the winter only. I tried it 3 times this summer, and all 3 times were aweful. It seems like I’m the only one with that opinion though. Keep in mind, my usual XC setup is a 2.35" tire. It just feels like fat tires dont fit my riding style haha.

I ride a 4" tire, I can’t fit a 5" in my frame… so I haven’t tried any bigger on unis. I can tell there’s a big difference between 4 and 5 though as I’m riding the Bud-Lou combo on my Fatbike.

Flansberrium frames are coming back I heard… some guy told me he’s working on prototypes right now :wink:

You’re becoming a master at the art of teasing the audience! :slight_smile:

My (limited) experience is that fatties are great in snow and slippery surfaces, pretty good in loose, muddy and sandy situations and nearly unridable on high-traction hardpack situations with any kind of side-slope. (the Devist8or more so than the Larry). The fattest tire I have ridden is the 4" Devist8or. If I had a wider frame I would like to try fatter.

Too fat is when it doesn’t fit in your frame :slight_smile:

I had a Devist8er and after riding that and a 24x4" Vee Mission tire I was ready to swear off fat wheels altogether because I don’t have mud or snow and generally ride on harder pack trails with lots of changing camber which was terrible with those tires. However, I gave a 120 TPI Surly Nate a try and the difference is night and day. I’d like to try a Surly Lou if I can find a suitable frame.

I don’t live in a snowy climate, or a rainy one for that matter. But I do have easy access to beaches. So when I have an opportunity to order one of Jacob’s unicycles I want make a good decision. I’m thinking a 24 or a 26 that will take up to a 4 inch tire. Perhaps a 26er which I could always put a 24 inch tire on. Unlike buying from udc where you can always sell and buy again buying from Jacob requires a little more thought.

Opinions welcomed


I have been looking at the Kenda Juggernaught 26x4.0
Do you know if there are any problems with the Kenda tyre?

The wheel rim, tape, tube, tyre, and postage are only 98 Euros (around £80 / or US$115)
Add in an Oregon frame from UDC with some of their spare parts, and it should make a decent build project for a cheap, no brake, fat tyre Muni.

Oh I’m already looking into it. Bush wheels are freakin’ expensive though!

Sorry, I’m not into facebook. Are there any additional photos out there? Does this guy post on here at all?

There is no such thing as “too fat”.

More specifically I’d say rim width. A narrower rim will give a rounder profile, reducing contact patch, easier to turn, and more springy. Whereas a wider rim gives a flater profile, more grip, more stable, more resistant to pinch flats, and more damp over bumps. Also a heavier tire/rim combo would be slower to change speeds and direction.

This added to which tire used and the added sensitivity to tire pressure. I use a digital gauge accurate to a half psi. With some tires I need much higher or lower psi to get a similar response from the tire, on the same rim.