It’s not the size as much as the tire profile. That tire looks pretty square with the side knobs, and square tire profiles are terrible for unicycles. Any kind of side slope keeps pushing the wheel to the middle, you have to fight it the whole time.
And with higher pressure it will more noticeable.
Well damn. So even with higher pressure this is a bad tire? I’m going to have to sell it on Craigslist then. 
Really looks like the tire profile is the problem. In addition to that the tire compound could also be a problem especially when the it is made for wet surfaces. It will really stick to the ground then, making it feel like riding with way too low tire pressure.
Laaaaaaame. I just put it up for sale on Craigslist. I’ll stop by my lbs and see if they have a try-it-once-and-exchange-it policy. So bummed…I had such good luck with my last two tires. If I get a 2.5 again, what should I look for in the profile?
Don’t forget about rim size too - wide tires need wide rims. A 2.5 works real well on a 42mm rim, not so well on a 25mm rim.
Sam
Square tire profile bad for unicycles?
I must be in the minority because I disagree. My favorite unicycle tire is the good old Nokian Gazzoloddi. Still have a relatively new on on my KH24 and I used to ride a 26" version on my original MUni years ago. I’ll also say that if you’re running that high of PSI in the Gazz it’s no wonder you’ve had issues. Depends on your weight I guess but I’m 5’ 9" 145lbs and rarely run higher than 12-14 psi in my Gazz. 20’s and, gasp, higher would be awful for me. I know the trend these days has gone towards skinnier MUni tires and believe me I’ve tried to embrace that trend as well but I’ve had the least trouble and most fun when I’m riding FAT. I think there is a learning curve for sure and yes at times it seems like you’ve got to exert a little more effort to tame the beast but at least where I ride and what I ride it’s all worth it.
The Gazz doesn’t have a square profile. It’s a fine MUni tire, heavy but for that you get to run with really low pressure which is nice for some kinds of riding.
Going fatter, the difference between the Endomorph and the Larry is night and day. It really depends exactly how the knobs are laid out.
The Gazz is definitely more of a square profile than Duro, the other 3" wide tire I’m familiar with. Just now starting to experiment with fatter unicycle tires. Then again I probably don’t ride near as frequently or as much as the regulars on this site. I’m just happy when I get the chance to get out and ride and perhaps I don’t know what I’m missing? I’ve always been the type to adapt to my equipment and not the other way around.
Some of this sounds like it might have something to do with the tire, but a lot of it might simply be due to the change. Your not used to riding with a big heavy tire. Going from a light mountain bike xc tire to a heavy thick sidewall downhill tire does a number on the handling of your ride. It would definitely take a few rides to get comfortable with it, especially if you’ve never ridden a tire like that.
It’s going to be very sensitive to tire pressure, there are a lot of people here who don’t like a tire until they find the right pressure, and sometimes the sweet spot is only a few psi. You don’t mention how much pressure you had in the tire, that really is important.
That new tire is only a 2.5, so you may be having kind of the worst/worst scenario… It’s not wide enough to give you the stable platform people like in the heavy wide tires, yet it’s really heavy at the same time…
I’ve bought plenty of bad tires, don’t worry about it, it’s how we find good tires eventually.
Definitely check out the tire thread Eric posted, LOTS of good information in there.
The stock tire on 26 Muni’s at UDC is the Duro wildlife leopard 26x3, that would probably be a good choice.
I’ll check out the thread once (if) I sell this one on Craigslist. I actually liked the feel of not needing to stand up over every bumpy/rooty section. My butt and crotch are definitely thanking me for getting a fatter tire. But the absorption of bumps was outweighed by the instability of the ride, so I don’t think I’ll give it another shot. My frame won’t allow for 3". The frame width is 2.9 inches, so I think 2.5-2.7 might be the fattest that I can go. I wish I had read the thread before buying this tire.
It sounds a lot like when I went from a generic 24" to my muni with 24". It was like learning to ride all over again, especially when I dropped the pressure down from 35 or 40 (which I needed just to be able to ride up any hill) down to the 20-25 I ride at now, and that looks similar to my Duro 24" in terms of the roundedness…
Just my 2 cents. In the end, ride whatever works best for you 
+1. Be careful about the rim you have as the rim width plays a good part on how a tire behaves when the pressure of the tire is low enough for it to deform.
You can give a look at the Muni tyre thread linked above, a lot of people are giving their feedback and even if YMMV, it is a good source of information.
Another way is to find riders with spare tires you can borrow and try. Much cheaper solution 
When I started riding on a 2.4” (the fattest available 20” tire AFAIK), I had to re-learn skills like the figure-8 in reverse. Before that, I had ridden a 1.95 Hookworm that I kept at 110psi on a narrower rim than the 47mm I have now. My fat, square-ish tire is nice for hopping, and it doesn’t make me dance the twist every time I ride on cambered pavement. It’s at about 40-60psi, I think. Once it wears out, I’ll probably go back to Hookworm, though.
I have a rim with 21.4mm inner width and 28mm outer width!! Which width do I go by in choosing a tire? Do you think based on my rim width, a 2.5 tire is too much?
I have the Butcher 2.5 on a DX32 rim. I really like it. The only thing I notice about it as far as handling goes is it soaks up imperfections to the point of feeling dead sometimes. To be fair as far as the pulling goes, I’m used to off-camber and wide tires (Surly Nate and Larry).
580g is really light for a muni tire. To get volume the weight will have to increase or the sidewalls will be too thin to do much good.
Tire pressure is key. A couple of pounds either way can make all the difference.
As far as the Butcher goes, it’s a decent sized 2.5. 930g is FAR from heavy.
If weight is a concern, NO on the Duro. It’s almost 1600g.
As far as good choices go, the tire thread is a great place to start.
There are also some new choices that are looking promising. I look forward to my Dirt Wizard coming in. It, however is around 1070g or so (wire bead). The folding is lighter (around 850g or so), but it’s still a lot heavier than what you’re currently running.
If you’re accustomed to a lightweight tire, a step to something almost 2x its weight is going to require an adjustment period. Getting something with a rounder profile is good, although tread pattern accounts for a lot too. I used a Continental 2.4 once that was fairly round and absolutely awful for muni due to knob squirm.
As mentioned earlier, the Gazz was (is) a great MUni tire; it’s not very square. But tire pressure is also a factor. On dirt, there’s a lot more leeway. but the Gazz on pavement was usually a pain to ride, high pressure or low. They just aren’t made for that.
A while back, I was trying to find an alternate (and cheaper) 24" MUni tire for my old Wilder. I bought a pair of something that looked good (I’m not at home to check brand & model); they made me buy a pair because of their minimum sale amount. That tire sucked! Bad on pavement and bad on the dirt. Same problem with always pulling to one side or the other. Kind of like riding on carpet, only worse. I tried all different tire pressures, but finally had to admit I’d wasted a bunch of money. No, I will not offer them for sale to unicyclists. Anyone want a pair of knobby 24" MTB tires for a 2-wheeler? I’ll look up the details if anyone is actually interested. 
Having a narrow rim isn’t a bad thing. You will just have to keep in mind that the bigger the tire, the rounder it will be because of the narrower base (your rim).
And with a wider rim, it will require you to run higher pressure than on a wider rim because the tire will folder over or just twist more on the rim because it doesn’t have as much of a lateral support.
I am doing some Muni on a 26" (65mm rim) and 29" (38mm rim) and I have fun with both. I am just not running the same pressure because of the different tires and rims.
Do not give up, it will be plenty of additional fun when you’ll get your tire right
Inside width. Think about it as the part of the rim that is squeezing the beads together. On a narrow rim the tires will measure narrower than they do on wide rims as well.
I may be interested for my son’s mountain bike. Let me know the width and I’ll see if they fit his frame.