V12 pulls to the left and right

[warren-r]

I recently got a V12 and after some practice got the hang of it. After refilling the tire, I noticed that the V12 will intermittently pull/turn while riding at middle speeds 10-20kmh. Previously the V12 would go straight and it would require intentional effort to turn. Now, it requires intentional effort to prevent it from swerving out from underneath me. What could be going wrong here and is there any redress?

The Inmotion app had the following features and settings that I've looked at:
* Diagnosis - it reports that there is nothing wrong and gives me a green check

* Turning Calibration - when I push the button it says "Failed"

* Balance calibration - its not tilting forward/backward, so I haven't done this

* Self-adjustment of Motor - not sure what this is or what it does. Haven't done it.

Any suggestions?

[Flygonial]

Assuming this is your first wheel, are you sure this isn’t just your first experience with a higher pressure and not being used to it’s squirrelly-ness? Though this video isn’t directly on this topic, it puts into words what I’m talking about better than I could. A lot of keeping an EUC stable comes down to micro inputs that eventually become ingrained (with proper habits, for example, wobbles eventually just become rare). When at a lower pressure, my experience does confirm needing to put in a sizable, deliberate input to turn (so much so that after having gotten comfortable I actually hate that inertia and like the responsiveness of a higher pressure), and when learning it’s possible that you’ve just not gotten as much of a feel for riding yet and what seems like pulling to one side is just the wheel responding to inputs you’re unconsciously making that didn’t do much at a lower pressure but the wheel is responding to now.

I don’t mean to condescend at all, so disregard if you already have a healthy amount of riding experience under your belt.

Of course, random problems with a V12’s behavior aren’t unheard of but it’s hard to imagine what control mechanism could be causing this in a device with only one wheel after all . If there actually is something wrong there, I wouldn’t know either.

Another possibility could just be that your tire isn’t quite seated properly. There are a decent amount of videos on how to read your tire bead and it is possible that this became a problem after inflating it up as well. If you notice the bead is off when spinning you’ll want to deflate and massage the tire while spinning it and in between reinflating pumps.

Also, if you let some air out of the tire and find that the wheel just keeps going straight then that should probably rule out anything being wonky on the software side here.

[mrelwood]

4 hours ago, warren-r said:

After refilling the tire

Sounds like you might benefit from checking the actual pressure on the tire. Inflating a tire by feel definitely doesn’t work. I’ve measured tires inflated by feel to be as low as 15 psi and as high as 45 psi. EUCs are very sensitive to the tire pressure, so using a pump with a gauge is the only choice.

 For the V12 HS with the stock tire I’d aim for 30-35 psi, depending on your weight. For the HT version I’d go for 25-30 psi.

[meepmeepmayer]

There is nothing that could be wrong with the wheel to cause a sideways tendency. EUCs only do things in the forward/backwards direction. So diagnostics won't be able to find the problem (if there is a problem) because it can't be a wheel problem.

As said above - either the tire is not seated properly or something like that leading to bad tire behavior, or you're just not used to a fully inflated tire.

[techyiam]

6 hours ago, warren-r said:

After refilling the tire, I noticed that the V12 will intermittently pull/turn while riding at middle speeds 10-20kmh. Previously the V12 would go straight and it would require intentional effort to turn. Now, it requires intentional effort to prevent it from swerving out from underneath me. What could be going wrong here and is there any redress?

What tire pressure are you using?

With the wheel resting on its side, tire off the ground, use one hand and spin the wheel. Does the outer tire diameter look almost perfectly round?

[alcatraz]

Like others have said... To me it sounds like a tire pressure and tire TYPE problem.

I had a similar problem even after riding the same tire that most people recommended here on the forum. As it turns out, that tire was the wrong tire for me.

Some tires are better suited for heavier riders and I'm a smaller rider. That means I need a softer tire. 

Really sturdy tires with lighter riders have the problem of becoming squirrely at low tire pressure. It's because (I think) the sidewalld are too thick and the pressure too low for that sort of rider+setup. The wheel starts to support itself on the sidewalls when turning, and not the airpressure alone. It does unexpected things.

I changed to a softer CST C1488 (cheapest tire out there) and my ride quality went from 1/10 to 7/10, even at low pressure.

Edited June 5, 2023 by alcatraz

[alcatraz]

A similar problem happens (I hear) when you ride certain knobby tires on pavement. 

[chanman]

Probably you've refilled it a bit too high pressure for your comfort. You can try to acclimate to the new feel, some people enjoy the responsiveness, but depending on your weight and what the current pressure is you might want to drop the pressure a bit.

[warren-r]

Thank you for the advice everyone! To respond to specific questions:

On 6/3/2023 at 2:03 PM, Flygonial said:

are you sure this isn’t just your first experience with a higher pressure

Yes this is my first experience with a high pressure tire. 

On 6/3/2023 at 5:59 PM, techyiam said:

use one hand and spin the wheel. Does the outer tire diameter look almost perfectly round?

Emphasis on "almost". It seems like it has a bump/uneven patch on it, but its small in both wheel coverage and hight.

On 6/3/2023 at 3:22 PM, mrelwood said:

you might benefit from checking the actual pressure on the tire

The tire says 35-45 PSI range. I had it at 42. I did a test run after reducing the pressure to 35 and it felt a little more stable, but the swerving was still there. Will try again with 30 and see. My concern is that having pressure below the recommended range will damage the tire. 

 

[Hellkitten]

4 hours ago, warren-r said:

My concern is that having pressure below the recommended range will damage the tire

It’s more likely you’ll damage your rim and or get a pinched flat. If you go to low. 

[techyiam]

7 hours ago, warren-r said:

Will try again with 30 and see. My concern is that having pressure below the recommended range will damage the tire. 

I see. I typically ride below the recommended tire pressures labeled on the tire. The tire itself doesn't seem to suffer any kind of damage, not even tread wear pattern. It is unlike a car or motorcycle, where tire pressures can have a negative impact on tread wear. This experience has been over 3 or 4 tires.

On my V12 (HS), I have ridden it at as low as 15 psi. No rim nor tire damage. But I only rode on pavement with no jumps, drops, boinking, stairs etc. I highly doubt you will damage your rim and tire at 30 psi, if you are still learning and will ride sensibly.

Edited June 6, 2023 by techyiam

[Punxatawneyjoe]

8 hours ago, warren-r said:

It seems like it has a bump/uneven patch on it

Perhaps the tube is pinched inside the tire causing it to misshape the tire. If it isn't even and smooth with no wobble, it can cause problems. I was noticing that my new v13 motor/tire/tube combination came with pinches in the tube from the factory. They stupidly use a 3.00/3.25 tube and it seems kind of large for the tire so i can wrinkle inside causing pinches and folds making the outer tire uneven.

[UPONIT]

On 6/5/2023 at 6:38 PM, warren-r said:

The tire says 35-45 PSI range. I had it at 42. I did a test run after reducing the pressure to 35 and it felt a little more stable, but the swerving was still there. Will try again with 30 and see. My concern is that having pressure below the recommended range will damage the tire. 

 

The original knobby tire on my V12HT had a well-defined groove on each side of the centerline, which meant it had a tendency to "stick" in those grooves when turning. It also was just too "grippy" on the street. The tread wanted to steer instead of letting me. I don't know if that contributes to your problem? I like the street tire I replaced it with much more. The tread is very similar to the V11's. No continuous grooves to fall into.

Also... I wouldn't recommend running the V12's stock tire below the minimum pressure. The innertube can move if the pressure is too low, causing the valve stem to tear at the connection point, making a leak and a flat. Ask me how I know.

Too high a pressure = too squirrely for me. Too low a pressure = the wheel rides kind of drunkenly because the tire has enough slack to slush around side to side.

As others stated, I would check that the tire is properly seated. If it doesn't run true (while in front of a mirror, lift the unicycle from both ends keeping it level, and let the wheel spin while watching in the mirror for wobbles) you can true it up yourself.  Also, make sure there is equal distance between the rim and the solid line that goes around the entire tire on each side (~3 mm from the rim). 

Let us know what you discover. 

PS - Which of the pedal positions do you have your pedals mounted at? Top, middle or bottom? Lower setting = lower center of gravity = easier balance. Check that all 8 pedal screws are tight.

[techyiam]

Do you have a V12 (HS), or a V12 HT?

[meepmeepmayer]

What happens if you ride the wheel backwards? Not you riding backwards, but stepping on it the "wrong" way and riding forwards as usual. If it still pulls to the same direction (relative to you), that would prove it's just you. If it pulls to the other side now, that would hint towards an actual wheel (well, tire/rim or at most motor) problem.

Edited June 7, 2023 by meepmeepmayer

[mhpr262]

On 6/5/2023 at 4:14 AM, alcatraz said:

A similar problem happens (I hear) when you ride certain knobby tires on pavement. 

Oh yes, the knobby tire on my Begode EX20S does this. It always feels like it wants to turn slightly left or right by itself, squirrelly. Not sure what tire it is, a CST 186? I forgive it though because the aggressive profile keeps the tube far away and above from any glass shards, thorns, bits of wire and sharp pebbles on the ground. Having a flat tire on one of my long tours, when I am hundreds of kilometers away from home is one of my worst nightmares.

[alcatraz]

On 6/11/2023 at 12:38 PM, mhpr262 said:

Oh yes, the knobby tire on my Begode EX20S does this. It always feels like it wants to turn slightly left or right by itself, squirrelly. Not sure what tire it is, a CST 186? I forgive it though because the aggressive profile keeps the tube far away and above from any glass shards, thorns, bits of wire and sharp pebbles on the ground. Having a flat tire on one of my long tours, when I am hundreds of kilometers away from home is one of my worst nightmares.

I think it's because the knobs are all in one line. They have a center spot that the wheel will want to balance on. That will throw the wheel into these certain angles, and out of the inbetween angles.

[Nostris]

On 6/6/2023 at 9:07 AM, techyiam said:

I see. I typically ride below the recommended tire pressures labeled on the tire. The tire itself doesn't seem to suffer any kind of damage, not even tread wear pattern. It is unlike a car or motorcycle, where tire pressures can have a negative impact on tread wear. This experience has been over 3 or 4 tires.

On my V12 (HS), I have ridden it at as low as 15 psi. No rim nor tire damage. But I only rode on pavement with no jumps, drops, boinking, stairs etc. I highly doubt you will damage your rim and tire at 30 psi, if you are still learning and will ride sensibly.

The pressure stamped on the sidewall of the tyre is the Maximum Cold Tyre Inflation pressure …. Which is usually 40 psi.  This is the never exceed pressure…not the recommended ridding pressure. The newer wheels often use motorcycles / Motor scooter tyres, not bicycle tyres. The motorcycle type tyres are usable at quite low psi..unless you like big jumps, running up curbs or riding stairs. 

[Nostris]

On 6/3/2023 at 5:04 PM, warren-r said:

I recently got a V12 and after some practice got the hang of it. After refilling the tire, I noticed that the V12 will intermittently pull/turn while riding at middle speeds 10-20kmh. Previously the V12 would go straight and it would require intentional effort to turn. Now, it requires intentional effort to prevent it from swerving out from underneath me. What could be going wrong here and is there any redress?

The Inmotion app had the following features and settings that I've looked at:
* Diagnosis - it reports that there is nothing wrong and gives me a green check

* Turning Calibration - when I push the button it says "Failed"

* Balance calibration - its not tilting forward/backward, so I haven't done this

* Self-adjustment of Motor - not sure what this is or what it does. Haven't done it.

Any suggestions?

To calibrate the wheel, it must be resting on its kickstand.  As for the tyre..if you have an HT, it’s almost certainly because you have it over inflated. The HT tyre is very unstable when over inflated and riding on pavement. It wants to constantly fall off the central vede of the tyre, to the left or right. Reduce your pressure until you find your sweet spot. 

[techyiam]

1 hour ago, Nostris said:

The pressure stamped on the sidewall of the tyre is the Maximum Cold Tyre Inflation pressure …. Which is usually 40 psi.  This is the never exceed pressure…not the recommended ridding pressure.

I suppose it depends on the tire. On mine, it is stamped 35 psi to 45 psi.

[alcatraz]

I don't know about you guys but I'm nowhere close to the maximum pressure. I'm always on the low end because I prefer comfort.

And when I say low, I mean low. A 3in wide tire I'm likely around 15psi. But then again I'm lightweight and ride a thinner tire.

Just letting the OP know that the pressure goes hand in hand the riding weight. You can't just copy other riders' tire pressures and expect similar results if they weigh differently.

And no, you can't really jump around on 15psi unless you're a featherweight. The comfort is nice though. If I had the pressure set up as high as most other riders I'd lose out on a large chunk of comfort. You just have to be careful not to bottom out or you'll mess up your rim.

I'm not sure I'd put more air in the tire if it was a suspension wheel. For max comfort they'd work together.

Edited June 29, 2023 by alcatraz

[mrelwood]

1 hour ago, alcatraz said:

I'm likely around 15psi.

How do you prevent the tire from slipping on the rim and ripping out the valve at those pressures?? Did you glue the tire onto the rim?

[alcatraz]

It's not loose. With my 65kg riding weight I compress the tire about half way. It doesn't move around on the rim. 

My pressure gauges are not accurate so I'm just eatimating the pressure. I can without much effort press the tire inward with my thumb. (not the bead area)

[UPONIT]

15 hours ago, Nostris said:

The pressure stamped on the sidewall of the tyre is the Maximum Cold Tyre Inflation pressure …. Which is usually 40 psi.  This is the never exceed pressure…not the recommended ridding pressure. The newer wheels often use motorcycles / Motor scooter tyres, not bicycle tyres. The motorcycle type tyres are usable at quite low psi..unless you like big jumps, running up curbs or riding stairs. 

Ditto what @mrelwood said about too low pressure allowing the tube to slip inside the tire and tear the valve attachment point. I know first hand.

Also, too low a pressure can introduce the instability of "slosh," where the tire can kind of slosh side to side because it is so squishy, which feels almost as bad as the "falling into a groove" instability of the stock tire.

There is definitely a weigh-dependent sweet spot at the low end which I love. On the tire I replaced the stock tire with there is no continuous groove problem. It is almost identical in tread and profile as the V11 stock tire, which I find very stable and cooperative.

Edited June 29, 2023 by UPONIT

[mrelwood]

3 hours ago, alcatraz said:

It's not loose. With my 65kg riding weight I compress the tire about half way. It doesn't move around on the rim. 

My pressure gauges are not accurate so I'm just eatimating the pressure. I can without much effort press the tire inward with my thumb. (not the bead area)

If it’s just an estimation, I guess there’s hope. But 15 psi is loose, and has been a cause for several torn tubes. Which of course ends up as a crash, because you can all of a sudden no longer steer.

 Your weight actually works against you here since you exhibit less pressure on the tire, so it’s easier for it to spin around against the rim.

 Be careful, and at least monitor the valve stem orientation and angle.