My 29er wants to turn to the right, but my 20er does not. Why?

Hello all,
A couple of months ago I learnt to ride an unicycle and I love it, really. I had an old 20er unicyle which I was able to ride in a straight line… and I am still able to…
Then, I decided to go for 29er for longer distances. Yesterday, I started to try this new uni, but I have a problem I do not know how to solve: it seems to me like the unicycle wants to turn to the right all the time, I mean, I try to go in a straight line, but I have to push more on the left pedal to keep the direction… well, it is hard to explain (also, sorry, English is not my mother tongue).
I think that (of course…) it is my fault, but I do not think I am doing anything very different compared to the 20er.
So, what could I try? Something to take care of that was not noticiable on 20 but it is on 29? For me it feels “almost” the same. I also found a thread on this forum about “turning” and it was full of good advices, all make sense, but I think I already tried most of them (as far as I can…).
Well, I know it is a strange question, but I am a bit lost here. I guess it will only take more practice.

Thanks for any advice!

After turning the seat…

I followed some advices and turned my seat 180. Now it keeps turning to the left instead! What does this mean exactly? something is bent?

If you are serious in your query, YOU SHOULD NEVER put the seat in the frame the wrong way round. That effectively means that you are riding the rest of the unicycle backwards. The pedals, which have opposite threads to each other, will come loose and damage your cranks. This is 100% serious advice.

Back to basics. The frame has a slot at the top, which allows the frame to grip the seat post when you tighten the clamp bolt. Conventionally, this slot goes at the back. On most frames, it isn’t crucial, but it’s a convention and looks better.

Next, look at the cranks. Usually the left one will have an L on it and the right one will have an R on it. Look on the inside face of the crank (the side of the crank you can’t easily see!) and it’s usually near to the hole that the pedal is screwed into. It is absolutely vital that you have the L on the left and the R on the right.

The right side pedal has a conventional thread: clockwise to tighten.

The left side pedal has a left handed thread: anticlockwise (US = counterclockwise) to tighten.

Therefore, it is impossible to put the pedals into the wrong cranks.

You must have the left crank on the left because you must have the left pedal on the left. If you don’t then the simple act of pedalling will unscrew both pedals and it will damage the threads.

If your uni was set up correctly in the first place, and then you turned the seat round 180 degrees, the effect of that is the same as if you had set up your uni with the cranks and pedals on the wrong sides.

I cannot stress too much how important this is.

Moving on from that, why is your unicycle turning one way? I can think of 4 likely explanations.

  1. Your seat may be at a slight angle instead of exactly in line.

  2. The tyre (US = tire) may be too soft, which can cause a uni to squirm and develop a bias in one direction.

  3. It may be the camber of the road. Most roads and paths have a slight slope across them to aid drainage of rainwater. This means that you are riding across a slight slope. Many tyres, even when they are at the correct pressure, tend to turn up the slope slightly. With experience, you can overcome this, but it is irritating.

  4. You may be sitting unevenly on the saddle. Most people have one dominant foot and one weaker foot. If you are concentrating on a new and difficult skill, you may be putting too much force through one pedal.

The fact that one of your unis is turning one way and the other is turning the other suggests, but does not prove, that (4) is the least likely explanation.

Other explanations are available! Good luck.

I think the problem is that your 20" used to be a children’s bike back wheel, but your 29" is from a mountainbike front wheel, of which the steer was stuck. Which is why they took off the wheel. You still feel the impact of that.

Thanks for your comments!

Don’t worry, it was just a test, a short run, just to see how it behaved. This unicycle is new, I bought it last week, all was already assembled but the pedals and the saddle. I also had to adjust the disc brake a bit. The seller has also asked me to ride it for a while backwards.

  1. It seems ok to me, I don’t have the right tool to measure it. In any case, I wonder if this could be the problem despite I cannot notice it at first sight.

  2. I also bought a small pump with a manometer and I did adjust the pressure up to 45 psi approx. It is a muni actually, so it is within the margins. The tire claims to allow from 35 to 80 psi.

  3. I am pretty sure the effect is constant, no matter which direction you are heading on a given street. I tested it on many streets, roads…

  4. It is still not clear to me, but I think that the goal of doing the ride-it-backwards thing, is to discard that possibility. Forwards, it likes right, backwards it goes to the left instead. If my dominant foot were the problem, it would turn to the same side always right?. Actually, now I think the title of this thread is misleading, this has nothing to do with the 20", but I don’t know how to change it…

You are now officially the first person who made a joke to me in English, no reward sorry :wink:

First guess would be lack of experience along with strong suggestive power to turn the opposite direction because you turned the seat around, therefore, the uncontrolled turn will be opposite.

Second guess might tire bead not setting properly.

This narrows it down to the unicycle assuming that the road, rider, and crank length stayed the same, while the seat was in line with the wheel for both rides. My assumption would be that your wheel is dished towards what would normally be the left side. When you turned the seat around the wheel was then closer to your right side.

I’ll attempt to do a diagram of what I’m thinking here. The ‘|’ on the outsides are the frame sides, a ‘.’ is just a unit of distance, and the ‘()’ on the inside is the wheel.
Normal: |.().|
How you got it: |()…|
When you turned the seat around |…()|

If you have only been riding for a few months then you will probably adjust after a little more saddle time with the 29”. Otherwise you can true your wheel with a spoke wrench. There’s plenty of good videos on YouTube to explain how to do that.

This is possible but unlikely. Wheels are built on a jig which includes a guide to ensure that the rim is the right distance from the flange. I’d look at the simple stuff first: tyre pressure, camber, straightness of seat, seat height, and practise more.

An update

A few days ago, I carried the uni to a bike repair shop where they found the wheel was not centered. They have a measuring tool (don’t know the name, sorry), which has three points of contact with the wheel: hub and highest and lowest points on the rim. So, by aligning tool and wheel on one side and comparing against the other side they could see a difference of around 1.5mm. Also, It was twisted a little bit.

At this point, they are fixing that. We will see if that is the (only?) reason, but for the moment I would be curious about the maximum allowed deviation on the trueness of the rim for an average unicyclist to be able to notice it… I am not an expert, but I would bet that 1mm is neglectable… or maybe not?

Im pretty sure a small wheel offset wont change anything. Mine is 5mm more toward 1 side on my small uni and it rides just fine.

My 29 was really hard for me to ride when I first got it. i felt like i was constantly twisting to go straight, and would end up with my feet at odd angles on the pedals due to the weird contortions. It smoothed out over time until it was fun to ride. Then, when I got my 36, the 29 suddenly felt very natural and the 36 was hard to control.

Absent a larger wheel, time in the saddle is the key.

Update 1.1

The uni came back from the repair shop and I rode it for a few days, a couple of hours in total. Nothing changed. So, I can tell you that 1.5mm disaligment does not make almost any difference (as you said above). I said almost because I think I feel it different, but it keeps turning to the right anyway.
Well, I am completly lost. If I turn the wheel (the wheel with hub,cranks and pedals attached, all these together since these are the only pieces I can not flip one by one), it turns left instead. The frame is ok, the seat is also ok, if I flip them, the uni keeps turning right as before. The only thing I still did not check is tire bead, as commented by Canoeheadted, but at first sight the tire seems to be in its right place.
So, lacikng any idea to try on the uni, I think the best choice is to keep practising all the week long. My left leg is going to complain, a lot… If the problem is coming from me, I should see some progress by the end of the week… or not… I am also looking for any uniciclist somewhere near Pontevedra(Spain), but didn’t find any so far (I think we are even below the average here…). Thanks for all the comments!

OK time for drastic measures. LOL.

Turn your seat a good amount to the RIGHT.
When you are riding it, this will make the wheel point left.
Let us know how it goes…

Was it a new uni? Maybe the previous owner biased the tyre with wear.
Or maybe the tyre is faulty.

Try putting the tyre the other way around on the rim.

What model is the tyre?

Unlikely to be wrong, but are the cranks exactly the same length?

It is even more “crazy”. At least, not better.
Actually, when I ride, I find myself placing my knees a bit to the left to try to put more weight on the left side, turning the seat to the right is a bad thing for this, I guess…

The uni is new.
The cranks are the same length. At the beginning, that was my first though as that is the feeling: left crank seems shorter than right.
The tire is Kenda Karma L3R Pro, 29x2.2, 120 TPI casing. It seems ok to me, I also tried different pressures. Anyhow, as you say, I already have an appoinment to flip the tire in the repair shop, I will tell you soon how it goes.

Update 1.2

How come? I did flip the tire, finally. Now, it turns left. So the problem is the tire. But how is that possible? I don’t see any defect and the job was done by a professional, not me…

The Karma has a dual compound construction with harder rubber in the middle and softer on the sides. Maybe something went wrong during manufacture and the transition knobs are softer on one side than the other?

Did it do this right from the first ride? Or could it have developed from wear on a cambered road?

Or maybe it did something bad in a past life.:wink:

Hi fuxo, what have you done about this issue since? Changed your tire?

I changed my offroad tire for a road tire and it cambers to the left.
I switched back to my offroad tire and I don’t have this issue anymore. I need to do like you did, by putting the road tire front to back and see if it cambers to the other side.

My new tire is a SUPERMOTOX 27.5 X 2.4

Hello again, I wished to write a reply weeks ago, but since then, the situation is even more confusing for me… changing the tire solved the problem in the first tests, but after some time, the problem came back… or maybe I did not notice it at first… or it appears from time to time… well, I don’t know what to do.

A few days ago I realized that there is some play between cranks and hub when I loosen the cranks’ bolts, so I can tighten them again with the cranks in slightly different possitions. It is less than two degrees I would say… don’t know if it has something to do. I will try to test this next week.