Wrong direction for tire pattern on inmotion v13?

[Finn Bjerke]

Wrongway? 

https://www.facebook.com/share/p/h8MVJo2fZGbFHZ8i/

[Finn Bjerke]

 

[Eucner]

10 hours ago, null said:

Are these wheels in the picture shown from front or back side? 

[Eucner]

15 minutes ago, null said:

Shown from front. (updated to show it)

Thanks. The acceleration and braking force vectors are drawn on the wheel as free body forces, but they have ground force direction. Because Newton's 3rd law of motion, these forces are in opposite direction.

[Eucner]

41 minutes ago, null said:

Yes they are opposite in the start (why I didn't start my arrows in the middle), but because material packs and pulls, the forces will spread outwards.

That was not the problem.

Thanks for the photo. As seen from the front of wheel, the red arrow is acceleration ground force and green arrows are opposite forces in the tire. Their vector sum is zero (Newton's 3rd).

Your arrows are showing the displacement direction. The spring equation is F = -kx. The direction of force is opposite to the displacement.

[Eucner]

50 minutes ago, null said:

You could just have said that from the start

My bad. I just tried to say it multiple ways to maximize chances to get understood.

50 minutes ago, null said:

point is to show what difference the installation direction makes to us.

Yes, thank you taking this tire pattern direction question to more concrete level. For any conclusion's, we need to have correct names and directions.

[Eucner]

1 hour ago, null said:

So, to get through with this, correct me from this draft:

1: I will replace "acceleration forces" and "braking forces" with "Displacement direction resulting from accelerating" and "Displacement direction resulting from braking".

Sound good. You could also call it deformation.

1 hour ago, null said:

2: I will curve the arrows so they start parallel from the center, as well as add a disclaimer that it doesnt stop after the arrow head.

5: I will use a single arrow for each "Displacement direction" to avoid any confusion regarding spread from origin, as well as make it on both sides so it is clear that this doesn't happen on a single side. It might even be better to make a gradient radiating from the "contact patch", but that isn't as intuitive when it comes to visualising the squishing on the groves, which is still, I believe, the only point that have any incident in our use case (and barelly so).

The displacement is largest at the middle of tire and practically zero at the bead. If the arrow could start thick at the middle and get thinner to the bead?

1 hour ago, null said:

3: As for arrow heads: they currently point away from the center because that is the direction the material takes relative to the entire tire. If you mean it is better to show the motion of the material relative to the contact patch, so inwards, do tell me. Or if all of this is wrong.

Displacement/deformation arrows should point outwards and force arrows should point inwards. I think here the interest is only in the deformation.

1 hour ago, null said:

4: Regarding colors I have used green to show the direction where the tire is most rigid, so parallel to the groves. Red have been used to show the direction that is less rigid, because it compresses the groves going accross them. To simplify green is the better spread, red is the less optimal spread. Should this be different?

I don't think there is a universal standard for color usage in this application. Use what you like and let us know their meaning.

1 hour ago, null said:

6: I will mention that the water flow arrow is purelly the direction the grove guides it when turning, but that surface tension and centrifugal forces are also at play.

That's a good idea.

1 hour ago, null said:

Anything else?

Keep up good work.

Edited February 7 by Eucner

[Eucner]

17 minutes ago, null said:

In the meantime, for the sake of it, here is a simplified version intended to leave out as much possible confusion, and focus solely on the compression on the material due to braking or accelerating. Tell me if any wording or technicallity is wrong and I will corect it.

That's good for me. Not necessary to add into the picture, but if somebody is interested, the reason of differences in material rigidity is how they add up as springs. In green direction they are in parallel configuration. The relation of displacement and force is more linear than in red direction, where they are in series configuration and more progressive.

[Eucner]

9 hours ago, null said:

Edit: While I think of it: On the opposite side of the contact patch we have pretty much the same deformation, but as a stretch (expansion?) rather than a compression.

Yes, that's partly true. There is difference how rubber behaves when it is pushed against ground or pulled off. The first one has longer contact patch. The compression side can also buckle and the stretch side can't.

The rigidity of tire comes mostly from ply layers. The variation in road tires tread pattern will have much lesser effect. So, perhaps no need to dig this too deeply.

The tire wear comes from deformed rubbers slippage under the load. The wear gets exponentially bigger when slip increases.

Regarding the water flow direction, it is also important to note what happens in cornering. The front tire pattern will spread water out of the corner and rear tire pattern into the corner, which is bad because that's the way we are going.

[Punxatawneyjoe]

On 2/6/2024 at 3:59 PM, Finn Bjerke said:

Wrongway? 

Short answer, NO

[Eucner]

On 2/9/2024 at 2:47 AM, null said:

Yes, I did a visual to better show the deformation of the pattern and we can see a bit on the profile how the stretch side do not buckle where the compression side does a little. Not being a simulation it is not entirelly correct and do not take in consideration the structurality of the pattern, but it shows how the displacement in one case goes in the strong direstion of the pattern whereas the other one does not. (Here a 2cm displacement of the contact patch on a 80/90-14 tire, just an example to be readable)

There should be 4 pictures. There was no tire pattern difference in your pictures. The direction of movement was missing. The deformation of tire should be similar in both tire pattern orientations. When accelerating the contact patch moves forward and when braking backwards. The contact patch is more elliptical than oval.

Edited February 10 by Eucner

[Eucner]

On 2/9/2024 at 3:01 AM, null said:

@Eucner Let's get over with this as it has taken way too long allready, but last question: I was using the work "forces" in my first illustration because I have been using that word for energy (?) in structures. I suppose gravity is a force. Say we have a cantilever beam, subject to gravity, it pushes and pulls on its fixation point, what should then this energy be called if it is not a force? 

I don't know how this relates to the subject. Gravity is pretty constant, so not much pushing and pulling. Gravity is a force, which creates deformation in the structure.

[Eucner]

44 minutes ago, null said:

I have spent hours changing this visual because you said the word "Forces" was not the correct one in the first version, I just thought you could have told me what it was after all this good will from my side. I am not refering to deformation, but to whatever "energy" (?) is travelling from "spring" to "spring". Re-reading your posts it is maybe "free forces"? Never mind, I am so done here.

Actually at the first I said your force arrows were in wrong direction. Then I said the arrows were in the direction of displacement. It's your presentation and up to you if you want to show forces, displacement or something else. Just label it correctly and have right direction.

44 minutes ago, null said:

- No, there doesn't have to be 4 pictures, there are only 2 different positions of the patch relative to the rest of the tire (and of coursee all the in betweens and side versions when turning, since everything has to be said). The bold text mentions which two cases each illustration reffers to.

- That information is baked into the sentences in bold "when braking as front tire" and "when accellerating as rear tire", (and their opposite) as well as showing the neutral center position and the moved position of the contact patch. The information is there, it is just not in the form you prefer, or bothered to understand.

- Yes, that is what my illustration show, albeit without arrows because I'm tired ow wasting time on this. The information is there, in text. Do you think I just made a random picture without knowing where the patch was moving?

When acceleration and braking the thicker part of tire will be on the different side of contact patch. Hence there is 4 different cases. You can condense them into 2 pictures, if you add 2 arrows showing moving direction for accelerating and braking.

44 minutes ago, null said:

- If you do not see the difference between the one where the groves are pushed close and the other where they are not I can not help you. I even allready told you it helped to flip between the two aftern clicking for full frame viewer. Do you think I would have spent time on two illustration where there was no difference?

I followed your orders, and that's how I found errors in pictures. I didn't ask you to make any pictures. It has been your free choice all the time. I've spend some time trying to help you, and that's my free choice.

44 minutes ago, null said:

Till now I could push myself to think your nit-picking was good natured, now I do not think so. I believe you are getting high on feeling superior by trying to humiliate me. At best you are "on the spectrum", but I do not think so. I will no longer try to be helpfull to the community by making illustrations if it's for getting jumped in this way. And note that it isn't that I can't take criticism or correct an error, I have accepted a lot. It is your boderline insulting stance which is the issue. I will also no longer read nor address you.

Your pictures will be helpful when they are correct. I assume that's also your goal. I'm sorry if I haven't been able to be clear enough in my communication. I feel you not being fair to me.