Thanks to whoever it was at the Unimeet who persuaded me that 40 psi was not enough for the skinny tyre on my new 28, and that 60 psi would be about right.
I had a lovely 4 mile walk back to the car, and am under investigation by the RSPB for startling an estimated 1,573 gulls and crows when the tube burst with a sound like a shotgun. 
Mike,
I missed the meet so canāt be blamed.
I have the same 28" and have run it at 75psi since somebody persuaded me at the BUC that 50 was too low. 
My personal view is this Uni loves high pressure tyres - guess you were unlucky. Think I might start carrying some spares on my evening rides, 4 miles pushing a Uni does not sound pleasant.
Keith
All is explained! Clearly some poor factory worker in Taiwan was so busy thinking, 'These bicycles weāre making are all going to be sent back - clearly not enough wheels, any fool can see thatā¦ if I was in charge thereās be a few changes round here, I can tell you, ā that she wasnāt concentrating on putting the inner tubes in straight.
When I took the tube out, I found that it was folded back on itself in a zig zag, taking about 2 inches out of the length, and obviously putting a strain on it.
The new tube I bought also seemed a loose fit when flat, so I put a bit of air in it and took extra care bedding it in before refitting the tyre. Iāve never noticed this as a problem with any other wheel size. Perhaps itās a 700c thing?
No complaints, anyway. Itās a learning experience, and it was a nice walk.
naw,you may have a 29er tube or a 27inch tube.both could be stuffed in a 700c,but would be slightly to big.
P.S.mike if you want real fun on your 28(29er) get a WTB nanorapter tire for it and a 29er tube.its about 2.1 wide and makes it a true mini-Coker.
The tube was marked 700, so I guess it was the right size.
As for making it a true mini Coker, my grand plan is that each of my unicycles has a clear identity and purpose. I decided on this after I realised that I was using my 24 and 26 almost interchangeably and āwastingā limited storage space in my back room.
So: 20 is for performing with the Morris men and practising ātricksā.
24 now has small cranks and medium-knobbly tyre which makes it a real blast on flattish but broken ground, and competent on footpaths/bridlepaths. I think of it as āthe hovercraftā.
26 is a MUni and I accept that the longer cranks make it slow but capable. I think of it as āthe tractorā.
Coker isā¦ well, the Coker.
And now the 28 is for road use only.
Makes sense to me, anyway. My guess is that the way things will develop, Iāll put 89s on the 24 when Roger gets them in, then transfer the 102s to the 28. Should make the 24 even sillier, and perk the 28 up a bit.
i had 102ās on my 29er,they were fun but if had to do it again iād go with 110ās.
hereās pic.look at those dingy cranks and that fat 700c nanorapter:)
I must make a rare admission of ignorance hereā¦:o
700c is one of those new fangled metric sizes (only been around for 20 odd years) and I donāt quite understand it. In my day, bicycle tyres were 27 x 1 3/8 or, if you were in a hurry, 27 X 1/4. Really sporty types rode 27 X 1 1/8.
So this 700 c thingā¦ 700 mm = 27.6 inches which I guess is a near approximation of the tyre size. (Mine is about 28 inches, but I can see why they wouldnāt want to call it 711.2c:) )
So, whatās the c? Is it the rim width? I ask because the tyre on the Nimbus is like really narrow - not far off racing bicycle width (perhaps Iām showing my age hereā¦ not far off what racing bicycles used to have in my day!). Will the rim take a much fatter tyre? I would have thought it would pop off the rim under severe stress.
As I said, the 28 is provisionally intended for road and easy dry tracks only, as I have a Coker for road and rough tracks, a 26 for real off road, and a 24 for being very very silly on. Still, it canāt hurt to ask, because a mini-Coker (fast Muni) would be much easier to maintain and repair than a real Coker, so Iād risk more on it.
So, whatās 700c in laymanās terms? 
as far as i know the 700 series of rim sizes is a French measurment system.its just the most popular one these days and has been for about 15 or so years.the 27 size is a little bigger circle but its being fazed out.
hereās a link to add some confusion or maybe clear things up.
the 2.1 nanorapter was pretty wide for my rim but it was the widest touring rim i could find and it worked fine as long as i pumped it up to 65psi.
I have Jagurās 29er and I love it. This is one versatile machine, I have a full range of cranks which I swap for the type of riding I want to do. I have no problem on single track downhill trails with 170ās, uphill is a bit of pain because Iām not that strong. With the 102ās I can fly along the paved bike paths (and even stop given enough planning time). Yesterday I had the 102ās on and was out on one of the popular biking paths, as I passed a small child on training wheels I heard him say āHe looks like supermanā (I was wearing a long sleeve blue shirt and a bright read safety vest). Most of the time I ride with 127ās as they seem to give me the widest range , with them I can ride the paved trail at a good pace then off road on (flat) single track for great fun. This is on the 29" WTB Nanoraptor on a 48 spokes and a w-i-d-e tandem rim.
I jumped on Lewisā 29-Raptor, Saturday (before my fall) -boy, does that thing accelerate fast! If you want a special thrill, try riding it indoors and play chicken with the walls. Spoking it to 48 sounds like a good idea; anybody taken stairs on one, howās it hold up?
-Christopher