What size cranks for 10 year old for MUni

I was out cleaning out the garage can came across my old Profile trials wheelset with cobwebs on it and 145 mm cranks. I haven’t ridden it in years and I seldom rode it when I had it. A few years ago, I bought the second generation KH wheelset with the steel splined cranks.

I have a 10 year old, too, yeah, but he’s not gathering cobwebs. He does lie around though, and talks back from time to time.

I digress.

He rides a unicycle now, but very seldom. We have been out only once on some flat single dirt single track on my old starter steel rimmed 20" with 125mm cranks. We rode about 1 mile. It’s got a white tire that’s good for gym riding. He did quite well, but struggled with the slight grade, as would be expected as his level.

Well, I got to thinking, maybe I could swap out the old steel wheel set and give him the Profile wheelset. The tire is an old Monty trials tire with about half the tread left. Thinking maybe the added torque would help. Seems like a waist to give him a Profile hub to MUni with, though.

I also have my old Muni with a Gazz 3.0 on it and 170 mm cranks on it. That might be an option, but I think the cranks would be too long. That’s currently on loan to another rider until they buy their own Muni. Not sure when I will get it back, and I can’t let him ride my Muni because of seat post issues.

I might add, that my son, doesn’t seem to have the love of unicycling I had when I started or what I see other young kids that unicycle.

So, here’s my main question(s)

What would you suggest I do?

  1. give him the Profile wheelset
  2. sell the profile wheelset and buy a new 20" wheelset that would be not as overkill as the Profile. (though, UDC carries nothing like this on their website that would be cost effective.)
  3. or just sell the Profile wheelset and then buy a whole new starter 20" Muni for the price I estimate I could sell the profile set for. (that assumes there is still intersest in buying a Profile wheelset anymore, since KH products have come out.

Your comments…


give him the profiles to ride. its free (you already have it), its easy and it should do a good job for him. and i think a 24*3 would be massive for him to the point he would struggle riding it

I rode a trials unicycle (KH 20" with 140mm cranks) for about a year and a half for everything, trials, muni, street ect, and it was great, except now that I am bigger and have a KH 24 I love it for muni, it is so much more tank-ish.

However, I don’t think a 10 year old would fit very well on a muni (I’m 14 and my seat is lowered as far is it can be, so I would recommend a trials unicycle with 125, 135, 137, or 140 mm cranks, because the profiles really measure 150mm, and so for muni you would only be able to go really slow, and you would hit your pedals on every other rock.

I hope that made at least a little sense :slight_smile:

I’ve ridden with a couple of kids of that age on 20" trials, seems to work well for them. It’s kind of like a mini muni, compared to their size it’s more like a 24/26".


Just to echo, a trials uni is good for kids that age. My now-13 year old rode our Summit when first hitting the trails, but now rides my old 26er muni.

FWIW, if you do a quick search on eBay right now, there’s a Qu-Ax trials. Who knows what it will end up going for, but it’s just $75 ($25 shipping) and ends in a couple days. You may be able to get it for what your Profile wheel would/will sell for.

Oh, and as for the motivation/enjoyment part … my experience with any activity is to let the kid dictate the pace and choices when he comes along. If he comes along and has some fun, then he’ll want to come more often. It doesn’t hurt to bribe a little on the way home, either (a stop for slurpees is a tradition with us).

With the 145s he probably will have a lot of pedal strike on cornering, otherwise I imagine keeping the Profile version would be great.

However, if he’s not really that interested, then take it at face value and don’t make uni decisions based on the possibility that he might want to ride someday. It’s pretty easy and cheap now to get a decent beginner-intermediate unicycle should he ever get interested.

Just my opinion!

My 8 YO uses a 20" rim (not 19" trials) with a big, but light, tyre. I think he’s currently using 125’s, if not he’s back on 114’s.

As Joe says size (and weight) it is equivalent to an adult on a 24/26". If he tried a 3.0" Gazz there is no way he’s strong enough ride up steep hills or hop, the wheel would be too heavy.

For my 11th birthday i got a 24 inch muni with 170mm cranks and a 3.0 gazzalodi tire like you were describing. I can tell you i loved it, even at that age.