Nimbus rim is 42mm wide right? You can generally get away with running a tire of equal width as the rim. You should be able to put pretty much any tire down to a 1.75 on that rim.
Aha! That makes perfect sense. Thanks very much!
Sounds about right - I quite often run a 2" tyre on my Nimbus 26 and that isn’t too narrow for the rim - you could certainly go a bit narrower than that without problems if you wanted to. I’ve used a 1.5" road tyre on that rim once for a road hillclimb, but that was really on the limit of practicality - worked OK though. Even for road riding though, a tyre with a bit of volume works better on a unicycle, so you don’t really want it too narrow (and the narrower the tyre, the smaller the wheel diameter will be, so it’ll slow you down a bit). Maxxis Hookworms seem to get good reviews, although I’ve never tried one.
Rob
I run a 2.5" Hookworm on my 26" Nimbus rim for the road and I am quite satisfied with its performance.
I also run a hookworm (on a DX32) for road rides and it handles very well but I can’t help but think that there is a lighter tire out there which will work just as well.
Sort of getting off topic, aren’t we?
This morning I had my first real ride with a 29x2.5 Kodiak and posted a (long-ish) review over in the Dissent/Kodiak thread.
I was going to post here but made a new thread on tire widths instead since it is really more about tire stats than a real review.
Check out “Tire widths on wide rims”
In the 29" size i don’t have all that much wheel time yet but I am really liking a WTB prowler on a wide rim.
Hopefully I will have a review up for the Vredestein Bull Lock soon since I just got one and it is even lighter than advertised (but not quite as wide as I was led to believe)
Arrow Wide Bide Link
Might as well post a link to this thread as well.
http://unicyclist.com/forums/showthread.php?t=82648
In all I am quite happy with my Arrow. when companing to Duro - in the future I would just go for the cheaper tire because both are pretty similair and each has it’s pros and cons.
There are some good pictures in the link as well.
Unicorn
The good, the bad, the Gazz.
Since this is the official review thread, I’d figured I’d post this bit of experience here.
I scored a couple of NOS Gazzaloddi 24x3.0" tires last fall. It inspired me to build up a Conundrum.
The good news is: the Conundrum is fabulous.
The bad news is: both Gazzaloddis would not stay on the Large Marge. The beads would not stay seated. The first one failed on the first ride. The second tire held out for a couple months, then unexpectedly left me walking home mid-ride. The beads seat consistently and evenly when mounted. After some riding they let go and slip off the rim. I tried completely reseating the tires several times to no avail. Once they fail, they continue to fail.
Duro and Intense tires work great on the wheel. They mount up a bit tighter (still using no tire levers).
I’m a good mechanic and have only had this problem happen one other time. It was on a questionable 1980’s 10-speed wheel.
Just a word of caution to those chasing the elusive Gazzaloddis.
How I destroyed a Gazz 
riding with low pressure on hard snow!
two things happened: the gazz got warped and started to touch the frame plus
it quickly showed the inner structure because the knobs did grind the surface of the tire.
Strange!
So I had to buy another Gazz : I really like this tire … but I won’t ride again with low pressure.
Nice so see that the new Gazz finally solved your strange tyre issue !
My Gazz had progessively been getting more and more of a twist in the tyre at two places, it was very fustrating and it started to rub the frame 
Then one day I put my unicycle down and I knowticed the Gazz had came off the rim, I tried to put it back on but it just came off again, like what happened to you it wouldn’t reseat so Iv’e given up on it for now.
Surly Larry
I LOVE the Surly Larry on my 26" Conundrum. I really wish I could fit this set-up on a KH frame… oh well, I may eventually upgrade to a Triton 
Big bouncy tire thatrolls pretty sweet at about 20psi.
the larry is really fantastic. it is big, light, excellent bouncing and has a good cornering.
an excellent allrounder.
it has less road resistance than the 3" gazza but also a little less grip and direction stability.
with higher pressure it becomes really dure with low presssure it becomes quick spongy so its sensitiv to pressure.
@GAZZALODDI
I had never problems with 26" x 3" gazza neither at 47mm rim nor at LM 65mm
I likewise scored an NIB Gazz Jr and had the same problem. I think as the tires have gotten old, the casing has weakened. I won’t buy an old tire again.
Now looking at the Intense Intruder 2.5-2.7
My son rides my 24 x 3" Intense DH and it is the best tire I have ever ridden, only I want to run something a tad lighter and narrower, so I’m hoping the 2.7will be as good as the Gazz Jr.
I’m 200# and I think that the tire reviewers sometimes fail to take into account the different ride characteristics of tires based on rider weight. I am trying out a Conti Diesel, which has sticky tread and a nice pattern, but being single ply it just doesn’t have the support for my weight. Running higher pressures makes it more supporive, but then it rides hard and bounces off obstacles.
I think two ply is the way to go for bigger rides or folks dropping big stuff. Too bad those kind of tires are falling to the way side
Im gonna have to say the best 24" tire ever built was the Nokian Gazzaloddi I beat the living poop out of mine on the North Shore and in Moab and it never failed even one of the tires I had about 10% tread left on never let me down.
Two high volume featherweights
I tried out a couple new tires last night which I had great hopes for. Both tires are really light and fairly wide. Here are my preliminary reviews.
Vredestein Bull Lock 26x2.35
I bought this tire based on the advice given to someone else looking for a high volume tire under 1000g for riding a bike on snowmobile trails. He was told that they were in the 660g range and measured as wide as some 2.7s
My tire weighs in at 680g and is 62mm (2.44") wide at the casing. That is a whopping 990g lighter than my Gazz, talk about loosing weight in a hurry.
I was riding the tire on my Nimbus/Echo 46mm wheel, Dual 165/137mm cranks in the 137mm position, and my new KH26/29 frame. I would have used 145mm cranks but they were on my 29" wheel which I was going to test next. 137 turned out to be a good choice since the light weight tire made it much easier to control with short cranks.
The first thing which was really noticeable was the light weight. As being ridden the unicycle weighed in at 6.2 kg. a full 2kg lighter than the steel frame and Gazz combo I am so used to.
Riding around it felt pretty good and absorbed the lumps and bumps OK but as soon as I started to test how it did in the hopping department I bottomed out right away. I added quite a bit of air and now the tire just felt hard. Some people like a hard tire, I am not one of them so I let air out until I could feel the tire give when hopping hard and the tire would not quite fold if I side hopped. this was somewhere around 30PSI which is a bit higher than my usual 20-22PSI.
I chased the dog around the yard and the tire just felt alive. It was very quick and stuck to the ground like I was running in cleats. I missed the soft rebound of a Gazz but the tire was really responsive. It took very little effort to turn, stop, speed up, or otherwise change my momentum and had incredible grip. I am thinking that this tire will become my preferred tire for rides on loamy rolling trails and suspect that it will also do really well in mud.
Schwalbe Racing Ralph 29x2.4
This is the ultimate in big and light. Measured on my 50mm speedway rim the tire was 63mm (2.48") wide and weighed in at only 590g 
Using the same frame and just swapping the wheel the unicycle was now down to 5.7kg. I think I might be turning into a weight weenie, but not enough of a weight weenie to loose the steel post mounted handlebar that I use.
I had similar experience to the Vred Bull Lock in terms of light weight and sidewall stiffness. I settled on 35 PSI with this tire. It had a bit more stability side to side but bottomed out a bit easier than the Vred at the same pressure. I think the side stability is from the slightly narrower tire being on a wider rim.
If the Vred was fast and responsive the Ralph was, um FAST AND RESPONSIVE. Seriously a tire this light with a light weight rim and 145mm cranks made for a very easy to control wheel and the rolling resistance was so low it almost felt like it was propelling itself.
The grip was good on hardpack and damp ground but it would wash out a bit if turning really sharply in looser stuff.
So a supper light and fast 29" tire with great volume but not the best for hopping and mediocre grip. I had previously used a WTB Prowler tire on this wheel and think that I prefer the WTB for the thicker sidewalls and better grip even if it is a bit smaller and heavier.
Conclusion
If you got a 26" MUni for XC rides what don’t involve a lot of hopping or dropping Go to Jenson USA and order yourself a Bull Lock (68% off). Very light for their size and it has great grip.
If you really want a light weight 29" tire the Racing Ralph seems OK but so far I think I preferred the WTB Prowler which is not really that much heavier but has a more solid feel with better grip.
Edit: While Gazzalodis are the hot topic I will throw in my experience. I have been riding a 26x3 Gazzalodi since 2006. It really did suck before I got a wider rim as it would just fold over then throw me when mounted on an Alex DX32 rim but I love it on a wider echo rim. Now that I have a decent rim to use with it I decided to upgrade my frame and got a KH29 frame and it is too wide. 3.15" and won’t fit between the legs without rubbing. When I am using my Gazz I am stuck using my old steel frame but in a lot of ways the weight is worth it.
Great write up! Like the info and the pictures, I love your 29’’!
I really want to get either a 26’’ or a 29’’, I have a 24’’ with a 3’’ gazz but want to get something faster and lighter.
Gazza 26"
by the way - If anybody don´t know how to get 26" x 3" gazza - I just have five in stock;)
@Sask: I’ve been pretty happy with my Ralph 29 x 2.4. Like you said, the grip on tight corners is sometimes not that great (on certain surfaces), but overall I find it excellent for fast xc. It does have very weedy sidewalls though (no thicker than a road tyre), and I have already had to repair a cut/tear in the sidewall of mine caused by slipping off the side of a sharp rock. You have to be more careful with it than you would with a beefier tyre, but for light weight, big rolling diameter, mostly race-orientated riding it’s really good. Running it tubeless makes quite a difference to the feel - seems to feel softer over rough surfaces without having to drop the pressure too much (which you can’t do with such thin sidewalls). Probably not a tyre for people who like side-hopping though!
Sometimes for general 29ering I think I’d prefer something a bit less damage-prone, even if it is a little bit heavier - perhaps I’ll have a look at one of those Prowlers next.
Rob