I finally got my brand new uni! This is my first I hope it will serve me well.

I am also thinking about a wider tire maybe a 20x2.5
(unicycledotcom says no way) but it looks like theres enough room. is the trials tire taller than a “regular” tire? What do you think? will it fit?

I can’t speak from experience, but as soon as you find out, let us know!

Won’t you need to buy and fit a 19" rim??

They said the frame is too narrow…and Yes you would have to buy either a monty or alex 19" rim if you want a 20x2.5 tire.

like everbody says, you’ll need a 19" rim and the frame might not be big enough.

there are other ways of course.

get somebody to mesure the width of a luna 19x2.5 (it says on the side wall 20x2.5 but the stuff written on tyres is completly meaningless)

mesure the width of your frame. you want about 1.5cm of clearance on each side

you can get away with less like 1cm but you’ll get rocks stuck in it.

in the old days before all the muni frames would take a 24x3 tyre, what people used to do was, stick the frame in a vice, and squish the forks to make the clearance bigger.(if you try this talk to somebody familiar with the process)

of course you could just stop bitching and apreciate the fact that youve got a lovely unicycle, that you wont break in a hurry, and thatcost you less than a hub would have a few years ago.

lucky git.

How selfish! The cost of that unicycle could have gone towards some nice warm clothes for those poor ladies in the background of the photograph.:wink:

Here, Here!!

But seriously, a 20x2.5 is misleading, and in fact, incorrect. It’s actually 19x2.5, which is still incorrect, cuz the actual diameter of the rim is 15.5" (by my measurement). A luna 19x2.5 tire is a tad bit less than 2.75" across. That means your frame needs to be about 3.25" across for it to have adaquate clearance. Also, it’s about 10.675" (10 and 3/8") from the center of the bearing holder to the edge of the tire. Now, grab a tape measure, and post the dimensions. Just so you know, in order to get a 19x2.5 tire, you need to get new spokes, a new rim, a new innertube, and of course, a new tire. That’s about $100 of equipment, and $60 to get someone to build you a new wheel. SO, quit fantasizing about some better parts, and get riding. Than, do some big move, taco your rim, and upgrade.

WOW! I was not aware that you needed a 19" wheel. that is very misleading! I am getting the hang of riding and turning and all the basics and stuff. I can’t believe the difference between this and my friends older econo-master uni(A.K.A. POS) The main reason I wanted the 2.5" tire was to soften the ride (my junk hurts!) what other (less expensive) options do I have? I tried less air pressure but it makes it harder to ride. Also I got this from a uni dealer in Pennsylvania for $114 plus$10 S/H I think I got a good deal.


You could try a fatter tire like the 2.3" Drive Load tire. DansComp has the Drive Load tire for $16.99. I’m guessing that the Drive Load tire will fit in that frame.

Also, get some lycra cycling shorts. They’ll keep your junk out of the way. Riding with boxers or briefs is just asking for problems.

I’ve got about 3mm on each side of my muni. If my design was followed correctly I would have had about 10mm but it’s not as bad as you’d imagine. Rocks don’t get stuck in there, they hit the frame and shoot out about 2m in front of the uni when I’m riding. This chips the paint unfortunately. But yeh, it’s not as bad as you’d think.

They did this for my frame and it’s still really solid. Yes, I’ve only got 3mm each side after having the legs crimped! :slight_smile:


Andrew, I have the same clearance problem on my muni. I have about 5mm of clearance with a yuni (24" version) frame, and I run an Intense 24x3.0 DH tire on a skinny Rhynolite rim, and my frame flexes enough that my tire rubs on pretty shallow climbs and steep descents. I’m getting a job though, and hope soon to get a Hunter muni with a magura brake (and profiles, of course).

The reason they say it is a 20x2.5 tire is because it is. They put the tire size on the tire. not the size rim you need. The reason you need a 19" rim is Because The 2.5" tire comes in further. so it has no bigger of an OD but much smaller ID. So you need smaller rim to fit it.

Are you suggesting a 24x3" tyre will not fit on the same rim as a 24x1.75? The outside diameters will be different, but the inside will be the same.

The 24x3" tyre on my muni has a larger overall diameter than the 26x1.75" tyre on my bike, suggesting that wheels are measured from the inside. Which makes sense, really; you can buy any tyre of the same diameter and know it will fit, however wide said tyre is.

20" trials tyres are an exception to this rule. I presume it’s because people started using normal 20" tyres and rims but then wanted something with a larger volume without increasing the overall diameter, and the 19" rim was born but not named according to the norm.


OK well I was thinking that a 24x3" was different…but that is the way it works with 20" wheels.

And 29" tires fit the same rims as 28" tires, they’re just bigger.
The diameter on a given tire is supposed to describe the outside diameter. This is an amazingly dumb an confusing system, and that’s why your 24x3 says 24 on the side of it and not 26; because it fits the same size rim as 24" tires. So now the whole “system” is both dumb, confusing and inconsistent. Some companies are trying to change this, but the system is hard to get rid of now.

I stand corrected… :slight_smile: I had assumed the measurement was the inside diameter, so they all fit on the same size rims, as anything else is… erm… an amazingly dumb and confusing system… :slight_smile:


Are you sure it’s the frame and not the wheel flexing? Maybe the spokes need tightening.


Yup, it’s the frame. If anything, the spokes are too tight. I built the wheel so tightly that I rounded some spoke nipples in the process. And yes, the wheel is very true (<.75mm of variance). The yuni frame is just cheap. I’ll replace it eventually.

Just checking. Why can’t they make good quality nipples? I know I’d be willing to spend up to $20 for a set of strong nipples.


Hi Andrew.

DT Swiss has high quality super strong nipples:


These are supposed to be turned via the hexagonal head. You should be able to tighten the spoke until the rim collapses with ease.

One of the three components has to fail when you apply much (too much) torque:

  • rim
  • nipple
  • spoke
    If you were to chose, you would take the nipple, I guess :slight_smile: