Essential Tools, Mechanical and Maintenence skills

Yes, I’d bet that some do use a torque wrench on ISIS cranks. Engineers and manufactures do recommend torquing the fastener to a specific torque for the best performance, but what do they know?

Here is a blurb on why they recommend a specific torque:
(from )

[I][B]What are the consequences of using too much or too little pre-load?

If a crankarm has too much pre-load it will not bottom out against the crank stop on the spindle when initially installed. This will lead to the crank arm “walking” up the taper during some initial rides and a consequent loosening of the crank bolt. If the bolt is not constantly tightened until the crank finally contacts the stop, the result could be the crank falling off while riding or damage to the interface.

If the crankarm has too little pre-load it will bottom out on the crank stop prior to attaining a press-fit with the spindle. Depending on the magnitude of the press-fit, this may result in anything from a slight reduction in the load carrying capability of the interface to a “sloppy” fit between the crank and bottom bracket. This may also lead to creaking of the interface due to the slightly “sloppy” fit between crank and spindle. [/B][/I]

With all that said my gut feeling is that the ISIS connection has enough reserve strength and has proven to be quite reliable that if the torque is not exactly as specified, you would likely be just fine.


Unicycle “ISIS” hubs do not have real crank stops, and our crank splines are highly variable in size and deformability. The KH Spirit cranks, for example, I have installed at spec with a torque wrench, only to have the splines deform, causing crank loosening (and eventually, Schlumpf coasting).

We sometimes use spacers in place of crank stops; my experience of those is that the spacers themselves are not to spec and can be of different widths on the same hub.

Since our hubs are not built to spec, torque specs should be viewed as guidelines, at best. “Crank it down really hard” is probably good enough.

Is the digital manometer actually a tire pressure guage or something else?

I am wondering if a highly accurate tire PSI guage is available, or necessary? Does anyone find themselves adjusting tire pressure on a ride for any reason?

That’s describing preload on the splines, not bolt torque. With our hubs the spline preload is set by choosing an appropriate spacer thickness. Once the bolt is tightened to the point that the crank is seated against the spacer adding torque does not increase the preload. At this point your concern is damaging the bolt/threads, not the splines.

Square taper is a different beast obviously as there is no spacer/stop for the crank to seat against.

When I read these above comments about ISIS problems, it makes me seriously consider whether or not I would be better off to make my next unicycle a QU AX with Q-Axle to avoid the possibility of these problems. It is supposed to be sgnificantly lighter and stronger.

I have read aboout some problems with the QU AX Q-Axle, but those seem to be more rare than ISIS problems and was due to improper assembly.

I most likely want to go for whatever is most bulletproof and trouble free, but still works good, and will be a positive ownership experience. AS I explore this, I do not like external disks nor holes in my rims. So QU AX looks better, at the moment, unless other brands put Q-Axle on their products.

I started this thread asking about the Q-Axle: Q-Axle questions

What ISIS problems? Don’t forget that discussions like this will be disproportionately made up of nerds like myself who like to pick every detail apart.

Your bulletproof and trouble free crank option is ISIS. It’s an open standard and you have many crank and hub options.

I’m sure Q-Axle is great. The spline + pinch bolt design is pretty common on bicycles these days (Note that bicycles have mostly ditched ISIS for this design, but it is due to problems with the bottom bracket bearings and not the spindle/crank interface.). The catch is that it’s a proprietary system available from only one company and will limit your options in terms of parts. Standardisation is a good thing IMO.

Maybe one day it will become more common, but for now I can’t really see that it’s solving a real problem. If you’re seeing more failure report of ISIS than Q-Axle it’s probably just because ISIS is vastly more popular.

At the end of the day the most important thing is that you have a unicycle which you enjoy riding :).

My 36" looks like no gap, but maybe there is one. Same might be true for my other close-fitting ones: DM ATU, Wilder and Roger Davies Carbon Muni (circa 1997).

Word of truth right here.

This might be offensive for some of the guys on here, and it’s certainly not true for everyone, but on this forum you will find many not very skilled unicyclists that prefer to spend their time overalizing why they are not getting better or experiencing problems than practicing.

I don’t think a single one of the riders in the Downhill final at unicon uses a torque wrench for their cranks. Or measured their spoke tension. Most of the riders I know could not even tell you what tire pressure they are running, because they just fill their tire, and if it’s not enough, you put some more air in, if it’s too much, they let some air out.

Perhaps, but the scientist and businessman will write down precise details and refer to them for future decisions.

I have heard the following comment from a few very good riders: When they were experimenting with a new tire, they had to get the correct tire pressure “dialed in” before the tire worked properly.

I experiment with tire pressure in the following way. Using my pump, which has a pressure gauge, I pump up the tire to whatever I think is right (a particular value on the pressure gauge), then I go on a ride. I evaluate how I feel about the tire pressure during my ride. I know that everything is a compromise. If I’m happy (if the tire doesn’t suck in a variety of conditions), next time I ride, I pump it up to the same pressure. If not, I experiment going higher or lower, then start the process over.

Sure, you can use the “feel” method. You will have to experiment, however, to get the pressure right. And you won’t be able to test all the aspects of tire performance at a particular pressure–while you’re hanging out next to your pump.

Finnspin mentioned the downhill. On a downhill tire, like the Duro, with its heavy sidewalls, maybe getting the tire pressure “dialed in” is not so important. I use a folding tire, the Ardent, on my 26" muni. Finding the point in tire pressure between what is rock hard…and where the tire starts folding, may be more difficult.

So, personally, I would say that the tire pressure gauge, while not indispensable, is a useful tool. I keep my large tire pump with the gauge at home, and carry a tiny pump in my backpack for emergencies on longer rides. I don’t change tire pressure mid-ride.

Finnspin, you hurt my tire-pressure-gauge’s feelings. Say you’re sorry!

They also experiment, and do so THEMSELFES. I’m not saying you shouldn’t ask questions, but 10 answers here will be less helpful than 2 hours of practicing. 30 opinions on what uni to buy will be less useful than having a go on one for 2 minutes.

Write down what you learned each practice session and see if it’s more effective (for YOU) to practice in two blocks of 20 minutes, or in 4 blocks of 10 minutes, or something else that matters. Go and collect your data about your riding, your preference in unicycles and your need in tools on the only appropriate subject: yourself. Asking others can point you in the right direction, but you will have to do the walking yourself.

I’m sorry it’s feelings were hurt, I’m sure it does a good job for you. I’m not saying they are useless, but what I am saying is that it’s really an item of convenience for people that are really particular about their setup, not something important. I’d also say that mounting and doing three hops is more accurately giving me the same pressure than any pressure gauge I have had on a pump so far.

I’m usually someone who overanalyzes too, but from my experience, you are usually better of adapting than planning ahead when it comes to unicycling. I can probably get used to a slightly more pumped up tire faster than it would take me to take the cap of the valve.

Regarding measuring tyre pressure:

  1. If you know the prefered psi, you can save time. Pump up your tyre to the desired psi and ride. No need to adjust tyre pressure out on the trail.

  2. If you don’t measure your tyre pressure, it will be a little different each time. It is a scientific fact that if you change a variable a little bit you will learn more and be better at what you do.

I usually choose no. 1


I learned long ago to make detailed systematic notes, keep journals, make goals and plans and revise them and to refer back to them on many things I do.

People often fail in business and other challenging ventures because they do not take notes, plan, or otherwise do their homework properly. I have seen people go through years of expensive education only fond they hated the profession it led to, or the education they got was worthless in the marketplace. I constantly see people screw up when they buy real estate, vehicles, appliances etc. and end up with headaches, disssatisfaction, and buyers remorse, losing money and wasting time because they did not do their homework.

Unicycling is a challenging task that a very small minority of those that try it pick it up quickly and naturally. I am definitley not one of them.

I am doing my homework to sort out equipment and training knowledge and while I am learning to ride, updating and making adjustments accordingly. That with stubborn focus and determination and I will succeed.

I have found that the various tire pumps and guages I have all give different readings. I suspect that the temperature even affects how much those inaccurate guages move. Still no one has answered my question as to any very accurate tire PSI guage availability etc. I want an accurate tire PSI guage for MY notes.

Very sloppy and unprofessional. Sounds more like weekend warriors out having fun, which is OK, than serious competition.

This would change if a lot of money or other highly motivating factor to win was at stake. Two identical riders of equal skill and determination, the one with the precisely tuned hardware who payed close attention to all the details, big and small, would be the clear victor.

If I was competing to win, I would want my hardware, body, and mind dialed in optimally. I would want every factor that my support team and I could think of to give me every possible advantage to beat everyone else on the day of the competition.

I didn’t pick it up naturally, but I made a lot of progress by actually riding it in the time I saved by not making notes.

Here are a few links about accurate pressure gauges:

Anyone that owns a motor vehicle could likely benefit from a good tire pressure gauge.


Just don’t forget to have fun :).

I am making more progress the last few weeks than the last few months from reviewing the notes in my unicycling journal and adjusting my practice sessions accordingly.

Many of the notes I have are from this forum, other online information and videos etc. I joined it when I could not find answers to certain questions using the search function.

If there was no internet and I had no books or instruction available I probably would not be able to figure this out at all. I only took this up when I saw people older than me learning how to do it and getting pretty good at it too. What do I see online, people asking how to learn to do it right, how to learn to mount etc. There was a lot of information that was helping people figure it out, so I thought that if they can do it, so can I.

Commenting here and getting responses to them has definitely been accelerating my unicycle learning process.