A few quick questions about trials unicycles

My wife has expressed interest in learning to unicycle. She’s short (4’ 10", barely a 25" inseam) so one thought was to get her a 20" uni to learn on and see what becomes of it and the other thought was that it wouldn’t be a terrible thing if I had a 20" uni (I’ve never had one) to skill build.

I was looking at the trials unicycles and was left with a few questions:

  1. I notice the rim is actually 19" and that there is a note stating 20" tires will not work on those frames. The prospect of replacing the tire was a bit concerning. Is it hard to find replacement tires? Will they always be around (there’s a pun in there somewhere)? A casual amazon search on the maxxis creepy crawler yields a 20x2.5 and a 20x2-2.20. Neither of which says 19".

  2. My wife is short, I’m comparatively tall. In looking at:


It appears that the top tube of the frame may already be short enough for her to reach the pedals with the seat in the lowest position. I’d rather not take a hacksaw to the frame if possible… but the backup/fail safe plan was to get a second seat post so I could ride it. I suppose this is an unfounded concern but one thing I found myself worrying about was whether the top tube of the frame was long enough to support a longer seat post - that is to say without creating a stress point where the top tube connects to the rest of the frame. Seeing unicycles like this:


Caused me to think that there must be some reason to have the longer top tube on a frame.

Just curious. Thanks in advance.

And it looks like my dreams of getting a 36er will have to be shelved for a while. :frowning:

My girlfriend is also only 4’10" and she fits on my nimbus 20" trials uni just fine. I’m teaching her to learn on it. In fact, she is even tall enough - if she had the ability - to ride my nimbus 29er with 125mm cranks with the seat all the way down and no modifications the frame. I also ride the trials uni, with the same seat post even, and it works just fine (I’m 5’10"). I feel like the seat is high enough for me, but you may not agree. I recommend getting a longer seat post than will work for your wife, and cutting it down until it fits.

I’m pretty sure that the longer neck is just so that the seat post clamp doesn’t catch on your clothing while you’re riding. I think the shorter neck is plenty strong enough. In fact, I don’t think the longer neck is even any stronger than the short neck. They both undergo the same amount of torque right at the crown, and I think that’s where the most stress is.

And as for the tires: one of those creepy crawlers you found is for the front tire of a trials bike. It fits a normal 20" rim. the other is for the back tire of a trials bike. It fits the special trials rim. I’m pretty sure they’ll always be around because people ride trials bicycles, and because there are a couple custom made uni trials tires, including the nimbus blizzard. It looks like the creepy crawler is currently out of stock, but here is the trials tires page on UDC: http://www.unicycle.com/unicycle-hardware/tires-tubes-rim-strips-and-valve-caps/tires-trials/

There’s other trials tires as well. Just search and I’m sure they’ll come up.

Thanks for the reply. I never paid attention before but now I find myself wondering. Why 19" for trials? Why not stick with the 20" rim?

And the maxxis creepy crawler on the trials tire link at UDC says 20x2.5, adding a bit to the confusion.

As long as Unicycle.com is selling the 20" trials unicycles, finding a replacement tire shouldn’t ever be a problem, you would just have to buy it from them. There are a lot of 19" rims out there being used.

If the tire thing was a real concern, you could go the freestyle uni route, I think cutting the frame down would be fine.

I am riding that same Uni (the trials in your first link), I use the 300mm seatpost and have no worries about the post being to long and stressing the frame (I’m 6’1" and 200 lbs). If you are totally aggro and 20 years old, it might be cause for concern, but most likely not. The kind of riding I do with that uni I have the seat fairly low anyway.

The last link there is a longneck, flatland/freestyle riders like that style so the seatpost clamp is out of the way for their tricks.

The 2.5 uses a 19" rim, the 2.2 a 20" rim. There aren’t many dealers in the US for trials tires. Try-All tires can be gotten from renegadejuggling.com

Check the trials tire thread to see all your options and why’s

I bet she could fit on any non long-neck frame w/ only cutting the seat post.

I would get a second post just in case your height difference is too great, I’d get it in aluminum. Also a second seat would make switches a bit easier and leave each seat/post together as a unit, this could also be an excuse to try a different seat, like Impact Naomi, Koxx, KH Street or Slim.

Yeah it is so you don’t nick the clamp w/ your foot while doing tricks, like leg wrap for instance. Plenty of people never have a issue w/ hitting the clamp on a normal frame. Also if you need to use a steel post to avoid breaking them every other ride, it would mean you could cut down the post more reducing overal weight.

Yeah, there’s about a 14-15" difference in height to contend with and her legs are short. In fact I have a 24" uni that has cottered cranks that I wanted her to learn on. We cut the frame down to fit and the seat is practically sitting directly on top of the tire.

Turns out it was a bust anyway because one of the cranks jiggles significantly and the bolt holding the crank on won’t tighten or loosen, I suspect it is stripped. It was a cheap-o uni that I had just to tide me over until I could find a schwinn back in the day.

I have a 26" nimbus muni and the seat post diameter matches up with the uni in the first link. I suspect my muni post will be too short for me on a smaller wheel so I’ll just be sure to get an extra seat post for me.

Your Muni post might be short enough or you may be able to shorten it enough so it’s still usable on the Muni and your GF on the trials, but if both are ridden by you and her, the constant switching will get annoying.

I’d get the second post/seat.

The trials bikers want a high volume, bouncy tire that will still fit in their bike frames, so they made the rim smaller and the tire bigger. That’s where the 19" size came from.

I mean wife

Well I just ordered it. Thanks for the info.

Hopefully I can use the trials uni to learn new skills and hopefully my wife will stick with it. :wink:

Your GF too.

Well I don’t know what she is going to learn on. :stuck_out_tongue:

You will never find a trials tire in a USA bike shop

They are made for mod sized trials bikes. Very rare in the USA. Uni riders adopted them because the tire and rims are much stronger than the older 20 " designs.

The price is OK cheap for trials tires, and they are better for off road and heavy duty riding. You will have to go to a specialty shop, like UDC or a trials bike shop to find them. Good tires though, just not standard bike stuff. Trials tires will only fit on a special trials rim. The whole uni is built up to a higher level of toughness. This is why trials unis cost so much more than most 20’s.