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Scott Dorand

18XL Wobble at certain speeds. (Solved - Rider Error/ Leg Fatigue)

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Posted (edited)

Hey folks, new rider here. Got my first wheel a few days ago and finally got the courage up to go for a long ride. At first I had the wheel limited to 18mph. But after a while I I was feeling confident and decided to bump it up a bit. So I set it to 24mph mostly to stop the constant “please decelerate” warning.

Everything went fine until I got towards the end of the the ride (about 30 miles). I then noticed at certain speeds (I think around 18-20) the wheel would pick up a side-to-side wobble for no apparent reason.  I’d slow down and it would go away. At first it was slight (2-3 degrees) but eventually it got so bad I was afraid I was going to get thrown off. 

When I got home I checked the battery and it was at 35%. My tire pressure is at 37psi. The ride is set to “Learning Mode” the wheel seems to be straight with no wobble when I spin it.

Could it be the lower battery? Maybe my legs getting tired? 

I’ve got it in the charger now and will test it again once it gets above 50%. But any insight would be appreciated. I’ve attached a few app screenshots for reference. 

91005427-70A9-4228-961E-37302B3BC6BA.thumb.png.c79ba42332ac20aadf9b74ebacadf9a9.png

73E0EE37-F032-4778-B5E9-78190EA8438A.thumb.png.0de1ad6ad39b467f1e2664b990cb4303.png

7198F208-CF9E-4B5F-85AF-75AE8A3EE2E7.thumb.png.0771adecb865eb4cbf3ef38cfe022779.png

Edited by Scott Dorand

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Sideways wobble is always the rider.

Much has been said about it. It's a feedback loop problem where everything and anything will constantly start small sideways imbalances, but an unrelaxed rider will no longer automatically equalize them, so they amplify into this wobble (faster at higher speeds).

Have a look: https://www.google.com/search?q=site%3Aelectricunicycle.org+wobble

12 minutes ago, Scott Dorand said:

Maybe my legs getting tired? 

That was exactly the reason. Your wheel is fine.

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1 hour ago, meepmeepmayer said:

That was exactly the reason. Your wheel is fine.

Thanks! I think you are right. Took the wheel out again and I was fine for a while but it started back up again towards the end.

I noticed on smoother surfaces everything was fine. But on a bumpier road (especially riding into the wind) I started to wobble again.

I think my foot position has a bit to do with it as well. My mounts are getting better but still not great. I’m sometimes uneven and I have a hard time adjusting my foot position while riding.

I’m pretty sure I just need time and practice to build up the correct leg muscles and coordination. 

In the meantime, I’m having a blast!

 

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Posted (edited)
47 minutes ago, Scott Dorand said:

I think my foot position has a bit to do with it as well.

Anything that influences how relaxed you stand on the wheel and let your subconscious do the sideways balancing will have an influence. Wheel ergonomy, stance, foot position, shoes, wind, experience vs. inexperience, mental attitude, good day vs. bad day, being distracted or not, being scared or not (sudden unexpected situation), happy or unhappy... it's all about being relaxed (or not).

Think of it like this: given a certain wheel, every rider has a specific wobble speed where the wobbling starts because the body can no longer keep up and do the automatic sideways balancing (it gets harder with speed because the tire rotates faster and imbalances will grow quicker and be more violent). The more relaxed you are, the higher that speed is. If you tense up (for whatever reason), the wobble speed is lower. On a EUC without speed limit, everyone will be wobbling eventually. Every rider is always not-quite wobbling until they are. The trick to riding is simply to have a wobble speed higher than your riding speed. It increases with experience and being/staying relaxed.

Regarding foot position specifically, if you step on while holding on to something and stand perfectly relaxed, check if the wheel moves. If it does, which means your center of gravity is not centered over the wheel, you will have to counter that all the time during riding aka use muscle tension to do that. That's one mechanism how stance/foot position can be good (relaxed) or bad (unrelaxed).

47 minutes ago, Scott Dorand said:

I’m pretty sure I just need time and practice to build up the correct leg muscles and coordination. 

Exactly!

47 minutes ago, Scott Dorand said:

In the meantime, I’m having a blast!

:thumbup:

Edited by meepmeepmayer
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Tire pressure has a lot to do with stability as well. A lower pressure will eliminate a lot of wobbles.  You will get better at controlling it with time.

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On 7/21/2019 at 4:48 PM, meepmeepmayer said:

Sideways wobble is always the rider.

Maybe, but then, how to get rid of it? In my case, problem is not a speed but acceleration load, for example uphills or against the wind, I tried different ways, tried to squeeze the wheel between the legs, or quite the opposite, kept it as free as possible, tried to shift weight from one leg to another, nothing helps, that thing keeps wobbling when pushed harder, I like my wheel, it's really superb, but those wobbles sometimes makes me sick:efef895ddd:

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1 hour ago, Gundars Balodis said:

Maybe, but then, how to get rid of it?

Practice. And a good (relaxed) stance to begin with.

I also learned that you learn rapidly when you challenge yourself. Do some crazy offroad or mountain ride and you will improve really fast.

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19 hours ago, meepmeepmayer said:

Do some crazy offroad or mountain ride and you will improve really fast.

Well, I'm doing fast every time I'm riding, not quite mountain, but steep climbs and descents here are the norm, I live in the middle of vineyards, for example a picture from one of my rides

1562944525970.9a13feae-1001-4e25-bece-844f8acea27a.jpg

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If acceleration and uphills are the problem, you might be standing too far back. If you are almost standing on your toes when accelerating, your feet will be very tense, and prone to wobbling.

Usually a good starting point is to have the back of one’s shoes level with the rear end of the pedals, and only toes hanging in front of the pedals.

When you search for a good foot position, always do a few very short accelerations and decelerations. If accelerating is more unstable or requires more effort than braking, you’re standing too far back. And vice versa.

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3 hours ago, mrelwood said:

Usually a good starting point is to have the back of one’s shoes level with the rear end of the pedals, and only toes hanging in front of the pedals.

I always try to stand in the middle, next time i'll try to shift forward a little, we'll see if thet helps, thanks for tips.

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