Best wheel size for Muni?

Unicycles and Equipment
5

My understanding of rolling resistance has to do with the continuous cycles of deformation and recovery of the tire which create inefficiency. The “roll-over” of a large wheel vs. a small wheel, to my understanding, is something different.

A large wheel may be moving faster and be heavier, creating greater inertia to lift the wheel over an obstacle. Assuming there is no tire deformation, a large wheel lifts itself over an obstacle over a larger distance, compared to a smaller wheel.

If momentum is lost, a relatively small wheel with relatively long cranks would power over obstacles better than a large wheel. I think it’s necessary to qualify the “roll-over” qualities of a setup with an indication of speed. So many “which setup is best” discussions are problematic because of differences in riding ability, trail conditions, what constitutes a “hill”, etc.

6

I wasn’t trying to be technical. I was trying to explain in my own words that big round things generally roll over stuff easier than small round things based on my personal experience. The person didn’t give specifics, so I can only speak in generalities.

7

These days, the 24" Muni size seems to suffer from a lot less choices of tire. They were very popular starting from the earliest days of Muni with fat tires, and I loved my Wilder with a 24x3 Gazzalodi tire (followed by others). But when I got my new one last summer, I avoided all the technical discussion and just got “what Kris rides”. :slight_smile: Of course Kris Holm rides all sorts of wheels, and is probably always testing the next thing. But when I’ve seen him at Muni Weekends, it’s almost always on a 26" Muni with a brake, which is what I got!

He has a Schlumpf on his, which is a possible upgrade for me in the future…

I think it’s the best machine for riding at decent speed on fairly technical terrain. If you like faster, flowy riding, go for a 29". If you can’t make up your mind between those two, I’d say get the 27.5" :slight_smile:

8

I love the idea of the larger cushion of a fatty, but a 26" ends up being 30" dia. This is too much for my property where I mostly ride a coupe hundred feet.
I see the only tire choice for muni 24 that is posted, only go to 3".
The mad4one website has a fatty that is 4" which is either Vee Mission Rubber rigid or CHAOYANG Big Daddy. These have a diameter of 26.75". This sounds like a great replacement for my cheap 24.
I am nervous that there aren’t any reviews on these tires. since I read about all the tracking problems they can have.

Does anyone have any insight about how they might ride?

9

The Vee Mission Rubber is about the worst tire I’ve ever ridden, road or mountain. Admittedly, I rode it on a fat bike, but the amount of auto-steer, straight-suck, whatever you want to call it, was atrocious even at moderate and high pressures. At low pressures it was nearly unrideable on the road. It was OK on dirt on a bike, but even my larry was much better grip wise and autosteer wise. The missions are made of really cheap rubber too and start disintegrating pretty fast. They may work for a 24 that you have a little more torque over depending on what crank size you run, but for a 26 fat, there are way too many options to justify it. If you had to go with it, I’d at least run it with the tred backwards, which seemed to help the larry out.

10

Specialized has a 24x4 with a nice thread pattern.
And the weight seems fair for its size

11

Thanks for the advice guys. I’m forming a 24 fatty plan.
If I can get a complete wheel setup, I should be able to make a frame to fit since it seems conundrums aren’t available.

12

spiker

Did you spike the tire yourself and if so how? Strava pics stock tire…

I’m wishing I had a spiked fat uni w/ the snow and ice now on the FR. Like to find a cheap Surly and spike it myself… Throw the 170s on it and go everywhere…

I apologize for thread hijacking…

Thx

13

At small to medium wheel sizes, an inch or two makes more difference.

For example, a 24" uni is 4/20 (20%) bigger than a 20.

A 28" uni is only 4/24 (16.7%) bigger than a 24.

This means that, all other things being equal, a 24 will be 20% faster than a 20, and a 26 will be only 8% faster than a 24.

Assuming a riding speed around 8 mph/13 kmh, all other things being equal, a 26 will only go 2/3 mph hour faster than a 24 - which is negligible.

However, all other things aren’t equal, because you need to consider the tyre section, the availability of tyres, your level of skill and confidence, and so on.

Also, because of the angles involved, a 26 will roll over things more easily than a 24.

Rather than going into the maths, think of these extreme examples:

A 2 inch wheel hits a 2 inch vertical step. It stops dead.

A 36 inch wheel hits a 2 inch vertical step: it barely notices.

Now apply this obvious principle to the 24 and 26 meeting a typical tree root. Whatever you decide to call it (angle of incidence? Angle of attack? Rollover factor?) the bigger wheel will always make less fuss about any given obstacle.

A fatter and softer tyre will also smooth out these small obstacles.

On the other hand, if you want to hop over an obstacle, the smaller and lighter the uni, the easier it is.

I ride and have ridden several unis off road on forest trails, rough tracks, uncultivated ground, and sometimes moorland. These include:

20 wth 125s
24 x 1.75 with 102mm cranks
26 with variosu cranks
28 x 23 with 114 mm cranks
29 with 150s and 125s
24 x 2.3 with 170s and with 150s
36 with 150s and with 125s

While you are just riding along the trail, there is no doubt that a 29 is easier than a 26 and a 26 is easier than a 24, as long as you are confident on that wheel size.

As soon as you need to stop, idle, reverse, turn suddenly, etc., the smaller size is easier.

End result: 3 recommendations:

If I could only afford one uni for general purpose including light off road, trails and the like, it would be a 29.

If I was never going to ride it on tarmac, but only on rough ground and trails, I’d probably go for the 26.

If I was going to ride the toughest stuff I could manage, and take risks, I’d go for a fat tyred 24.

14

Well, after a lot of reading and dreaming, I finally made a decision and purchased a KH 24 inch muni with 125/150 cranks. Yesterday was its madien voyage and I could not be happier. I rode for about 2 hours through a local mountain bike trail and although it’s noticabily slower than my 29 inch Nimbus muni at the same 150 crank length, I enjoyed its pivoting quickness and its brute force in climbing short steep hills. I even handled my first ‘unplanned’ 5 inch drop without a UPD.

As stated by many on this forum, selecting a unicycle “depends” on a lot of variables [juggleaddict]. It depends on where you ride, skills of riding, experience with riding other unicycles, what you want to learn to do and how much cash is in your pocket.

I love rough terrain riding. Cross-country and mountain bike paths are my current fascinations and slow to moderate speeds are good for me.

Since I did not have an opportunity to try out other sizes before making this purchase, I based my decision to buy the 24 inch KH on the following:

  • 26 inch would be too close to the ride of my 29 inch muni
  • a 26 inch would still be too high for me to practice new skills (At times, it can still be scary up there.)
  • traveling with a 24 inch in a suitcase or in the back of my care would would be easier
  • I’m not worried about having an external disc, because if I’d ever damaged the external disc, I will hang it on my wall with pride for riding so aggressive that I could do something like that
  • My history was similar to uniscott’s story (thanks for a sharing)
  • Schumpf insight from saskatchewanian
  • The Nimbus with the cranks and seat I wanted put it in the same price category as the KH
  • my local mountain bike trails offer technical tracks and cross-country tracks.
If I was only going to own one muni, it would be a 26 inch. If I was only going to own two mountain unicycles, it would be a 24 inch and a 29 inch (maybe with a schlumpf) If I was only going to own three unicycles, it would be a 24, 29 and a road 36 inch (it looks like I’m headed in this direction).

And to all for posted there stories and advice throughout this forum, I say, “Thank you.” I could not have made my decision without your input.

Hey, George J, machineman and gregolopogus,

How is your selection process going?

New uni suggestions: thread started by machineman

Some Muni Questions: thread started by George J

15

Unisphere, I ended up getting a KH 27.5. I haven’t ridden it very much since I broke my finger and I’ve been really busy with college lately, but I think it was a good choice.

16

George J,
Congratulations on your purchase. Based on your original post, it sounds like you made the right choice and with the dual hole cranks you can experiment with what gives you the climbing power you need.
I hope your finger heals quickly and without long lasting impact. Just know that your muni is waiting for you as you heal.

Be well and good luck with your studies.

17

No. You can buy them spiked. Google 26" spiked mtn tire there are several choices

18

If you want a DIY tire studding project I wrote a tutorial years ago. Unfortunately all the pictures disappeared into the ether, but it might still be useful.
Studding a MUni tire

19

Setup for road and moderately rough terrain?

Hi!
I’m pondering about a possible setup for moderately rough terrain and roads with short steep (max. 15%) climbs and descents. I do not want to go faster than 10-11 mph and 100 rpm.
Would the following setup make sense?
24" with Schlumpf, 170mm cranks

(shoe size US14, 6’2")

Thx for opinions!
Hendrik

20

I went the 24 29 36 option myself for my frequent riders, I have something in the area of 20 or 30 unicycles, even more when my fathers collection is in my garage.

21

24" with 170mm cranks? no no no … I would not do that.

Take a 27.5 with 150/127 double hole cranks.
If you don’t want to go faster than 11mph, you won’t need a Schlumpf hub.
If you also want to ride roads, I wouldn’t go any smaller than 27.5". 24" on road feels pretty slow, especially with 170mm canks.

22

Hi Hendrik

We are a pretty diverse group and difrent setups work for different people. A geared 24 with 170mm cranks might work for you but it is not a setup that I would consider.

Without knowing anything about your riding style, experience, or existing unicycle(s), I would suggest a 26 or 27.5 with 150mm cranks as a good starting point. If you like long cranks some 165/137 dual hole cranks would be a nice option.

One thing to note is that shorter cranks are more comfortable to spin at higher cadences than longer ones. 100 RPM might be a bit high on a bike, but is commonplace on a unicycle with comparatively short cranks.

I would hold off on buying the Schlumpf until you are a fairly accomplished rider as there is a learning curve associated with riding geared, as well as the small amount of free-play in the system.

23

As has been said, the best size for muni depends on the rider as well as the terrain…

Not sure how much riding experience you have, but I’m totally loving my KH 29+ for Muni with either 150mm or 127mm cranks. I thought I was going to use it for more light XC muni but I’ve actually been having a blast doing downhill on it too and have hardly touched my 26" in months (and the 24" is not even put together the last year). If you’re just getting into muni I’d recommend starting with a 26" with 150mm cranks (although 24" or 27.5 should work too).

24

Yeah… I used to run my 24 Muni with 165mm cranks with a huge Q-Factor. I could go up any gradient and had loads of torque for going down steep hills, although the huge amounts of torque meant that instead of sweeping down a steep descent in a swift manoeuvre, I would often lock up when the cranks were at the 9 and 3 o clock positions - which wasn’t great. On top of this, my pedals collided with the ground regularly, and they caused my thighs to rub against the seat much more than they would have had I had shorter cranks.

I couldn’t go very quickly, either…

I’m now running the same unicycle with 150mm cranks. I’ve not struggled to get up any gradients, nor down any (but then again, I’m maybe growing). I would be tempted by 138’s, were I not a cheapskate.