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Hsiang

So I decide to repeat the run that caused my faceplant 2 weeks ago..

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I got caught with a bad front wheel wobble on my motorcycle a couple months ago.  I rode it out safely, but I believe I know why it happened.  I waited too long to make a turn, then turned and banked sharply.  Unfortunately, my front wheel was underinflated and the sidewalls flexed too much.  This set up a side to side wobble as I tried to correct each change of direction.

I wonder if the same thing is responsible for sideways wheel wobbles on EUCs, especially ones with wide tires and thick sidewalls that people underinflate to cushion the ride.

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14 minutes ago, Thai-lad said:

I got caught with a bad front wheel wobble on my motorcycle a couple months ago.  I rode it out safely, but I believe I know why it happened.  I waited too long to make a turn, then turned and banked sharply.  Unfortunately, my front wheel was underinflated and the sidewalls flexed too much.  This set up a side to side wobble as I tried to correct each change of direction.

I wonder if the same thing is responsible for sideways wheel wobbles on EUCs, especially ones with wide tires and thick sidewalls that people underinflate to cushion the ride.

Low tire pressure is one of the causes of the wobbles on a motorcycle.   Not sure if it is the same on an EUC.   I tropically run my tires low, 28psi, I weigh 145lbs.   I’ve gone as low as 20psi without issue.   But these are not the fat 4” tires of the Z10.  Could be the Z10 more susceptible to wobbles due to the motorcycle like tire.  

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1 hour ago, Hermes said:

Ain’t no bicycle gonna pass me, fella! :P

Ok then go to Tour de France, and have a look when they do downhill...just a thought. 

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11 hours ago, houseofjob said:

@eddiemoy Sorry, but wobbles are still the rider / technique, Z or no Z.

Now, if you don’t want to learn that technique, that’s a whole different matter and completely fine. 

I’ve pretty much completely solidified my technique on the Z now, and hit plenty of bumps, both seen and unseen, most much bigger than the on in @Hsiang‘s video, and had no issues, no falls,... and I’m not fighting anything. (Actually, the sensation of hitting bumps/divots on the Z is much better than most wheels IMHO)

I know both of you guys like to squeeze the wheel, which I don’t subscribe to, but hey, to each their own,.... but the Z is very unforgiving to that riding style, I would get dumped on an unforeseen bump squeezing the Z as well.

For the Z and MSX, my feet are as wide as possible, almost hanging off the sides of the pedals, and for the Z, my heels angle even more outwards, like I’m pigeon-toed.

If I only stuck to traditional wheels that never challenged my existing EUC knowledge, technique, I would have never progressed... but hey, maybe that’s what people want. (eg, the wheels that forced me most to improve and better my technique were the oddballs: Z and KS18 tall series; a big reason why I love both wheels)

Hey @houseofjob I’m interested in your viewpoint as to why the heels are outward in your riding style (toes inward) as opposed to the toes being pointed outward (heels inward) 

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@Hsiang what tire pressure on the Z10 were you running when you hit that diagonal cut in the road?  And what speed were you going?  I thought maybe a higher tire pressure might tend to destabilize an EUC more whereas a lower one might cushion the impact better.  Maybe the higher pressure redirects the wheel in a different direction too quickly to compensate for.  Sort of like the same way higher pressure makes a wheel feel more “squirrely.”

As a mental exercise, imagine taking one of those red rubber balls we all used to play with in gym, pumping it up to a very high pressure so it’s taut, then drop it straight down on your toe.  It quickly will veer off in a random direction.  Now take the same ball, but let the air out until it’s soft and slightly under inflated and drop it again.  It likely won’t rebound off as quickly nor as severely.  I wonder if the same effect is happening when high pressure tires are hitting sudden bumps at speed.

I might go on to say that most likely hitting a bump straight on is less dangerous than hitting an oblique ridge due to the angle of deflection.  That could also explain why people’s experiences differ when hitting similar bumps.  Is there anyone out there with a high speed camera willing to run a series of tests hitting a two by four  at various speed, angles, and tire pressures?  :popcorn:

In addition, I may have figured out the reason for my fall.  I took a sweeping curve onto a sidewalk riser at the corner of a block.  In order to avoid the stop sign I curved to the left, but I hit a 1 to 1.5 inch rise between sidewalk concrete sections a little laterally at 62 psi and 22 kph which likely redirected my Tesla in a different direction so I got ejected.  If I had taken it straight on like I’ve always done previously I probably wouldn’t have gotten injured.

Edited by Hunka Hunka Burning Love
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1 hour ago, Darrell Wesh said:

Hey @houseofjob I’m interested in your viewpoint as to why the heels are outward in your riding style (toes inward) as opposed to the toes being pointed outward (heels inward)

I'm guessing this would be because heels out gives you a wider stance increasing leverage and therefore ability to precisely control wheel roll?

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5 hours ago, eddiemoy said:

Low tire pressure is one of the causes of the wobbles on a motorcycle.   Not sure if it is the same on an EUC.   I tropically run my tires low, 28psi, I weigh 145lbs.   I’ve gone as low as 20psi without issue.   But these are not the fat 4” tires of the Z10.  Could be the Z10 more susceptible to wobbles due to the motorcycle like tire.  

Well, I weigh in at 194lbs, and kept my 16" between 39 and 44 psi depending on tire. Going lower I found the thing unstable and with bad tracking. The weight difference between us probably explains part of that.

I have had two enlightening experiences of what happens when underinflated, both because of flats/leaks. One was a pretty drastic flat, probably a tube pinch, that happened in a curve and ended up with me in a sliding fall. To some extent I was lucky, as the rim could have been damaged, but wasn't. Another time I had a small leak, that lowered my pressure gradually. I started to notice the problem, as I felt a wobble coming on, which I controlled. Then at every turn, it became hard to turn and harder to right the EUC again afterwards. That was the point where I stepped off and checked WTF was going on. I felt the tire and realized it wasn't even close to the pressure I started with. I tried to ride carefully to a gas-station to get puncture foam and refill, but ended up having to walk the last mile - the EUC was totally uncontrollable.

Overall I'd say most wheels are more "comfortable" at a lower pressure, but at the cost of control and tracking. With my pressure up, I have had no wobble problems whatsoever. I've felt wobbles coming on from situations like @Hsiang's, but have had no trouble at all stopping them. Scary wobbles I've seen as something belonging to my first months of riding.

Maybe you should try your MSX at the recommended pressure. The tire is supposed to be big and wide enough to eat bumps even at pressure, and the tracking, stability and controllability should be a lot better.

Edited by Scatcat

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2 hours ago, Hunka Hunka Burning Love said:

@Hsiang what tire pressure on the Z10 were you running when you hit that diagonal cut in the road?  And what speed were you going?  I thought maybe a higher tire pressure might tend to destabilize an EUC more whereas a lower one might cushion the impact better.  Maybe the higher pressure redirects the wheel in a different direction too quickly to compensate for.  Sort of like the same way higher pressure makes a wheel feel more “squirrely.”

As a mental exercise, imagine taking one of those red rubber balls we all used to play with in gym, pumping it up to a very high pressure so it’s taut, then drop it straight down on your toe.  It quickly will veer off in a random direction.  Now take the same ball, but let the air out until it’s soft and slightly under inflated and drop it again.  It likely won’t rebound off as quickly nor as severely.  I wonder if the same effect is happening when high pressure tires are hitting sudden bumps at speed.

I might go on to say that most likely hitting a bump straight on is less dangerous than hitting an oblique ridge due to the angle of deflection.  That could also explain why people’s experiences differ when hitting similar bumps.  Is there anyone out there with a high speed camera willing to run a series of tests hitting a two by four  at various speed, angles, and tire pressures?  :popcorn:

In addition, I may have figured out the reason for my fall.  I took a sweeping curve onto a sidewalk riser at the corner of a block.  In order to avoid the stop sign I curved to the left, but I hit a 1 to 1.5 inch rise between sidewalk concrete sections a little laterally at 62 psi and 22 kph which likely redirected my Tesla in a different direction so I got ejected.  If I had taken it straight on like I’ve always done previously I probably wouldn’t have gotten injured.

I've heard report to the opposite, and they agree with my own experience. A higher pressure makes the wheel more "squirrely" as in "quick to react to input", which may feel less relaxed. But unless you go beyond the recommended pressures for the tire, actual tracking when you hit cracks and such is better. It's a bit the same as lower tire pressure being one of the main culprits to MC wobbles.

Of course lowering the pressure, will let you ride over bumps, tree stumps and such with much more comfort. But it will also put more force on the sidewalls, and deform the tire more. The centerline of the tire may move sideways because of a crack like the one @Hsiang hit. If it does, you now have an inherently sideways, unstable EUC - something that will actually become worse as the natural reaction to a crack forcing the wheel one way, is trying to steer the other. So you overcompensate and the wobble starts.

I remember @Marty Backe reporting that tracking of the Z10 got much better as he upped the pressure to more sensible levels.

Your accident sound much like my diagonal curb hitting one. Wheel one way, me the other. Hitting at an oblique angle ups the risk for a fall. If the tire doesn't immediately climb the curb/breach the gap, you get a sideways motion that are hard to get out of.

Edited by Scatcat
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5 hours ago, Scatcat said:

Well, I weigh in at 194lbs, and kept my 16" between 39 and 44 psi depending on tire. Going lower I found the thing unstable and with bad tracking. The weight difference between us probably explains part of that.

I have had two enlightening experiences of what happens when underinflated, both because of flats/leaks. One was a pretty drastic flat, probably a tube pinch, that happened in a curve and ended up with me in a sliding fall. To some extent I was lucky, as the rim could have been damaged, but wasn't. Another time I had a small leak, that lowered my pressure gradually. I started to notice the problem, as I felt a wobble coming on, which I controlled. Then at every turn, it became hard to turn and harder to right the EUC again afterwards. That was the point where I stepped off and checked WTF was going on. I felt the tire and realized it wasn't even close to the pressure I started with. I tried to ride carefully to a gas-station to get puncture foam and refill, but ended up having to walk the last mile - the EUC was totally uncontrollable.

Overall I'd say most wheels are more "comfortable" at a lower pressure, but at the cost of control and tracking. With my pressure up, I have had no wobble problems whatsoever. I've felt wobbles coming on from situations like @Hsiang's, but have had no trouble at all stopping them. Scary wobbles I've seen as something belonging to my first months of riding.

Maybe you should try your MSX at the recommended pressure. The tire is supposed to be big and wide enough to eat bumps even at pressure, and the tracking, stability and controllability should be a lot better.

I've tried recommended pressure, I get the wobbles when I use that.  I like it at lower pressures feels much more stable to me very rare wobbles.  I also don't get any of the tracking you you do.  I feel really planted when running on the lower pressure vs higher pressure is more squirrelly.  Maybe I'm just used to lower pressures or prefer it, not sure.  All I can do is relay my experience.  I guess we all have different ones.

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21 minutes ago, eddiemoy said:

I've tried recommended pressure, I get the wobbles when I use that.  I like it at lower pressures feels much more stable to me very rare wobbles.  I also don't get any of the tracking you you do.  I feel really planted when running on the lower pressure vs higher pressure is more squirrelly.  Maybe I'm just used to lower pressures or prefer it, not sure.  All I can do is relay my experience.  I guess we all have different ones.

Yes, we get used to our own setting, style an so on. If you're happy with the lower pressure, of course you should use it. :thumbup:

I just relayed my own experience with tire pressure, that is what I found when I fiddled around with different pressures.

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Wobble, Wobble, Wobble. I think there is something to be learned here. 

Some people are built different and / or use completely different techniques.  I have not worried about or had a Wobble that bothered me in any way sense my first week riding.

I can see that the Z10 has an issue with the wobble. The tire is wide and round. When you hit  one side of the tire as @Hsiang did in the video the wide tire forces the EUC to turn starting a Wobble. I can see that the MSX is the same to a smaller extent. The round edge of the tire enables the EUC to turn easier. Hitting something on the edge starts an unwanted turn creating a Wobble sequence. Some people do not seem to have as much of a defense to the wobble. Although Hsiang’s  crash is more of a perfect storm situation. The tire hits one side and then the other, perfect to create a wobble ( maybe adjust tire pressure)

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A proper wheel should be difficult to wobble regardless of tire pressure, the wobble once started should be of the highest frequency, and should dissipate almost instantly. I think most other design considerations should follow this philosophy. If wheel manufacturers only use good riders, it follows new riders will get chucked.

In my opinion, simply placing a large amount of the wheel's weight way out horizontally from the axle stops speed wobbles. You can confirm this by putting something as light as a speaker in front of your wheel (not the top) and seeing how that dramatically smooths out wobbles.

The Z10 looks like it has zero weight front and back. It looks like a wobble machine.

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I tried to put 50psi in my v10F - got really wobbly immediately, reduced to 30psi - (i'm 180lbs). It is very stable and pretty comfy ride

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14 hours ago, LanghamP said:

I have had a lot of track days and only recently got out of motorcycles entirely, due to cost and to the extreme danger of riding highly illegal speeds on the street.

EUCs are unsurprisingly similar, and possibly the same, as motorcycles, the caveat that EUC are by default unstable. It feels exactly like the front wheel of a motorcycle.

I believe there's a somewhat low practical speeds limit to EUC since instead of massive front forks we have feeble legs, and so speed wobbles that on a motorcycle would be entirely self correcting with no rider input no require lots of rider skill.

The inability of an EUC to dampen out wobbles is, to me, why EUCs will be stuck between the speeds of a pedestrian and a bicyclist. I don't see any foreseeable technology changing that.

This. I am sure some wheel are more stable at higher speed than others. But you can't overcome the physical limitation of having only one contact patch and no suspension. Potholes dips and rough patches comes in all shapes in size and coupled with the right (or the wrong) circumstances will cause a crash regardless of how good you are riding. IMHO one should only go as fast as one is ready to hit the pavement from, if you are not prepared/ protected to do so even 20mph is too much.

I think some of the new people whom watches videos made by experts on this forums see them go fast without much protection gets a false impression of stability/ safety. Where in the experts have their experiences as an additional safety net while the newbies would crash and hurt themself attempting the same.

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16 hours ago, Rehab1 said:

Promise we won’t laugh at your semi nude photos.;) Just watch out for @Hunka Hunka Burning Love ‘s subtle revisions.

32324733718_d8e1e58c55_z.jpg

 

I am not that pretty 😎😊

 

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I read again what I said about pressure, and realized I sounded like I'm putting 50psi into my tyre, while a truer number is 40psi. That is in a 16x2.125 tire, what pressure I will/should have when I finally get my MSX is yet to be seen and tested. The bloody wheel btw is stuck in the Xmas queue, and will probably be delivered in June or something... :(

I meat @Unventor and rode all of three meters on his 18L. I can well see why @eddiemoy loves that wheel, it is very substantial and just oozes of quality. If I had had my gear on, I would have ridden a little bit more, but I doubt my fedora would have helped much if I made a mess of it (sorry @Tishawn Fahie, but fedoras don't protect your head worth shit...) 

I quickly noticed that I'm unused to heavier and larger wheels, that will be a new and fun experience. We'll see if I'll love the MSX, I suspect I will.

 

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1 hour ago, Scatcat said:

I read again what I said about pressure, and realized I sounded like I'm putting 50psi into my tyre, while a truer number is 40psi. That is in a 16x2.125 tire, what pressure I will/should have when I finally get my MSX is yet to be seen and tested. The bloody wheel btw is stuck in the Xmas queue, and will probably be delivered in June or something... :(

I meat @Unventor and rode all of three meters on his 18L. I can well see why @eddiemoy loves that wheel, it is very substantial and just oozes of quality. If I had had my gear on, I would have ridden a little bit more, but I doubt my fedora would have helped much if I made a mess of it (sorry @Tishawn Fahie, but fedoras don't protect your head worth shit...) 

I quickly noticed that I'm unused to heavier and larger wheels, that will be a new and fun experience. We'll see if I'll love the MSX, I suspect I will.

 

Hehe I thought you gave up a little soon. On the other hand you did look like you were going to take away my pressures, if I may quote a skinny badly guy smelling of fish. 

I am pretty sure 10 more min your feet would not leave it ...until it needs a recharge. 😀😁

I hope the MSX falls to your liking.

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33 minutes ago, Unventor said:

Hehe I thought you gave up a little soon. On the other hand you did look like you were going to take away my pressures, if I may quote a skinny badly guy smelling of fish. 

I am pretty sure 10 more min your feet would not leave it ...until it needs a recharge. 😀😁

I hope the MSX falls to your liking.

Oh, when my helmet arrives (thanks PostNord for nothing, delivering it to the wrong bloody city), I may sneak in and steal it for an hour or two :dribble:

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3 hours ago, houseofjob said:

A big reason I advocate wide stances is for better stability, on both bumps/wobbles and turn maneuvering.

Within reason, the wider your stance, the more stable you are... all sports teach you this. 

The wider your stance, the more you take the physics of the wheel's dimensions out of the equation. Combined with mobile feet, almost no bump can knock you down, as a.) the wider stance gives you more reaction time than having narrow feet, and b.) the ability to move said feet lets you readjust, no matter what angle the wheel body is being influenced into (rider stays straight up, the wheel may not).

 

This is a very valid point, one I've been thinking about in contemplating how to go about technique videos (at least how I approach technique).

 

Heels out has to do with overcoming the Z's body/pedal physics limitations when turning.

  • Your average 18" EUC has a 2.5" wide tire, with pedals that are 5-6" off the ground.
  • The Z keeps the same 18" tire diameter and ~5-6" pedal height, only increasing the tire width by more than 50%.

The result is that, even with my usual adjusted wide stance, my outside turn leg kept hitting the Z body, not letting my leg angle deeper against said body for achieving deeper turns.

Trying to think why, I realized that a wider EUC tire width requires the pedals to be spaced proportionally higher, and the pedal width 'span' to be proportionally wider; so that a.) the pedals have enough clearance from the ground on tilt (as all components are now pushed more outwards), and so b.) the rider can position their legs in a manner where the EUC body side does not impede the angling downwards of that outside turn leg (again, due to everything being pushed out by the wide, both body & wheel).

Unfortunately, the Z was not fully optimized for all this IMHO; it really should have higher pedal height than the current setup, and optionally be a larger diameter tire than the current 18".

So.... in order to avoid my leg getting stopped by the Z body on turns, I go with my usual wide stance, but angle my heels even wider, so that, as the Z diagonally tilts, with slight dip down on turns (as any EUC does), I can wrap my outer turn leg behind the Z body, for an even greater angling, and resultant turn angle.

Best I can really explain it, without showing visually unfortunately :ph34r:

Keep in mind that although the Z10 is marketed as an 18-inch wheel, it's actually very close to 17-inches (I measured mine). And the MSuper V3 is closer to a 19-inch wheel and the MSX is close to 20-inches. Another reason why the "18-inch Z10" feels like a smaller wheel.

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2 hours ago, Scatcat said:

I read again what I said about pressure, and realized I sounded like I'm putting 50psi into my tyre, while a truer number is 40psi. That is in a 16x2.125 tire, what pressure I will/should have when I finally get my MSX is yet to be seen and tested. The bloody wheel btw is stuck in the Xmas queue, and will probably be delivered in June or something... :(

I meat @Unventor and rode all of three meters on his 18L. I can well see why @eddiemoy loves that wheel, it is very substantial and just oozes of quality. If I had had my gear on, I would have ridden a little bit more, but I doubt my fedora would have helped much if I made a mess of it (sorry @Tishawn Fahie, but fedoras don't protect your head worth shit...) 

I quickly noticed that I'm unused to heavier and larger wheels, that will be a new and fun experience. We'll see if I'll love the MSX, I suspect I will.

 

The MSX is not ergonomic.  Means you will need to be “conditioned”.  I feel that is just a fancy word for “it wasn’t designed right so here are some aches you need to get used to”.

I now know that if a wheel is properly designed and it fits you, not too small, there is no “conditioning”.    

Why is your MSX stuck for another 6 months?

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4 minutes ago, Marty Backe said:

Keep in mind that although the Z10 is marketed as an 18-inch wheel, it's actually very close to 17-inches (I measured mine). And the MSuper V3 is closer to a 19-inch wheel and the MSX is close to 20-inches. Another reason why the "18-inch Z10" feels like a smaller wheel.

I used to measure the outside diameter too.  But if you look at the tire, it tells you what size it is and it is based on rim size.  Though thicker the tire the bigger the actual diameter of the wheel is.  I guess that is where GW got its marketing from for the MSX.  Tire says 18x3, but they market it as 19”.  Kind of muddy all the definitions.  Just like rounding up their battery sizes while the other advertise the exact size.  There is a value to the marketing the bigger rounded number.  But there may be a backlash when people find out its misinformation.  Slippery slope. 

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1 hour ago, Marty Backe said:

Keep in mind that although the Z10 is marketed as an 18-inch wheel, it's actually very close to 17-inches (I measured mine). And the MSuper V3 is closer to a 19-inch wheel and the MSX is close to 20-inches. Another reason why the "18-inch Z10" feels like a smaller wheel.

Dear Lord, you've got Eddie talking about his favorite subject, measuring inches of rubber :roflmao: @Hunka Hunka Burning Love insert joke here 

The point was, widening the tire means you shouldn't be keeping the same relative other dimensions, IMHO

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