How does unicycling on an untrue wheel affect riding?

Well, I did some looking and couldn’t quite find a suitable space for asking this question. I wonder if anyone has wisdom about this. I realise I could true my wheel, I just was curious if anyone has any thoughts about this?

Last summer, some friends and I had the pleasure of riding Muni with a very accomplished rider from out of town, that was in town on a business trip.

His unicycle wheel was the most out-of-true unicycle wheel I have ever seen (it created in my mind the image of an “S-curve” in a road). When I mentioned it, he (being 25 years my junior, and apparently less concerned than I about items of this nature) simply shrugged and said, “I haven’t had a chance to take care of it. It hasn’t seemed to affect anything.”

I can confirm that if it did affect him in any way, there was no way for me to tell, especially as he navigated from the top of a sloping bank that lead down to a running creek, while stopping halfway and hopping up onto a fallen tree trunk and riding 25 feet on his way to the bottom of the hill/bank to arrive at the waters edge.

I learned a lot that afternoon. Least of which was that I can push my equipment much harder than I had been pushing it.


That’s very interesting. I am NOT that guy though. I am 59 years old having come to the unicycling world late in life. I noticed that my wheel is a bit more out of true than I thought it was because my magura rim brakes were rubbing today before I rode to work, so there’s that I suppose. I just moved the pads away from the rim where they were rubbing. So at the very least I was getting a bit of grabbing going on as I rode, perhaps on my last ride … I definitely noticed it. But I wondered about how it might otherwise affect my riding. I feel quite affected by road camber, and I wondered if the wheel being out of true would worsen that effect, or not actually make any difference.

I have ridden a rather untrue wheel before, but not for long. It was getting progressively worse, and then some aggressive side hops completely tacoed it. It was a side of the road find, either in a garbage pile or garage sale for cheap, I forget. I did find a decent rim off a dead b*ke and laced it on with exactly zero spoke measuring save for holding the rim next to the old one and eyeballing it to be close enough. Somehow it’s super sturdy, and really improved that uni. Another thought I have is that when riding uni we “fudge” continually. In the snow and after riding through a puddle you can see the oscillatory nature of our path, so a wobbly wheel might even make us smoother riders so long as it’s in phase with our cranks. Or it could worsen the effect if out of phase.

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Riding discomfort is the least of it. If you are in the habit of doing a few sidewalk drop offs be ready to find some broken spokes.

It would depend if it’s side to side or rise and fall and how fast you ride as you’ll feel it more at higher revs

From experience, you can get away with a fairly visibly out of true (10 mm side to side or more) rim and not have it affect your riding much.
At least with a wide tire and not very high pressure, I think the tire deforming can even out a bend rim in a similar way it evens out terrain. A slim road tire at high pressure might be a different story.

Regarding strength, with a bent rim and disk brakes/no brakes, it’s sometimes a compromise between making the wheel more true or having more even spoke tension. I might sometimes decide to leave a few mm of wobble in it, if getting it more true would require some spokes to be under much more tension than the rest.


My two cent:

A deviation in vertical direction will be anoying if it becomes big enough, but probably not affect balance directly.

Deviation in horizontal direction will add something to your effort neccesary for balancing. But since you have to work for this constantly anyway, it probably won’t make much of a difference. Plus, with turning of the wheel it will kind of move you around the middle, but always bringing you out of balance an back again in the same amount, so it would be kind of a self correcting problem.

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My apologies. I did not factor brake-type into my response. I can imagine that an untrue wheel would take on much more of an importance when using rim brakes.

yeah, the wheel is not out of round, i.e. the “vertical” deviation, but it is out of true, the “horizontal” deviation.

no problem at all.

I wasn’t sure how to feel about this subject so I looked at it a bit differently.

The RPM of a unicycle wheel traveling at high speed is much lower than most bicycles traveling at an average cruise speed.
I found this paragraph regarding how untrue wheels on bicycles may perform.

Untrue wheels are weaker, may cause steering to be difficult at high speed, and if you’re using rim brakes it will cause stuttering or lockups. Having said that, it would need to be damn untrue for any of the above to be a serious problem. It depends on the reason for them not being true.

I found the comparison enlightening. I’ll let you draw your own conclusions.

Unicycles move at such a slow speed, an untrue wheel is really not noticeable unless, of course, it has an extreme side wobble.

On a side note, I have a 1963 Lyod Unicycle, pre-runner to the Schwinn. It has pinned cranks, and for years one of the cranks was at least 1/2 inch offset from the opposing crank from jumping up and down — never bothered me!

thanks for your thoughts on this.

that makes sense. Thanks