PeteHski

I don’t see any point. It’s already been modelled in detail with published results and conclusions. I have no reason to dispute those results and my calculation would be far less detailed.

Your version of the maths fell flat on its face when you started off with a solid 13 kg wheel because you didn’t understand how to apply the equation you Googled.

base2 

Not only is this thread about irrational rotational, it's also circular in nature.

livedarklions

It's definitely been circling the drain.

Aardwolf

Widdershins or sunwise ?

livedarklions

Dunno, but there's enough crap in it to clog the plumbing.

terrymorse 

I'm experimenting with some tire patching methods to see how robust they are. The goal is to support the cut casing completely, so the patched tire is as strong as it was before the cut.

I recently patched a cut in the tread of a GP5000 (notorious for tire-killing cuts), using fabric reinforced butyl rubber sheet (1/16th inch) and super glue. It worked brilliantly, but the rubber sheet is rather stiff. I'm planning to test out other patch material, such as polyurethane coated polyester canvas.

In the "old days", we would cut up a worn out tubular tire and use the sidewall material as a patch, gluing it in place with contact cement. Most of us survived.

Carbonfiberboy 

That is an interesting video. I think it is however a bit biased by the slow speeds shown, and by the fact that bike riders instinctively countersteer. It's pretty obvious from the get go that one has to lean in the direction of the turn and the way to do that is to move bike out from under oneself. But notice that the riders move their upper bodies away from the direction of the turn. That's why they have to countersteer.

However if one is conscious about what's going on, one can move one's bodyweight in the direction of the turn well before allowing the wheel to turn in that direction. When descending at speed, I first drop my head into the turn, then my hip. No noticeable countersteer though I slightly counterrotate my body, maybe from skiing for 70 years.. I think that's a little faster and sets up the turn and weight distribution more gradually. There may be gyro forces involved, hard to know because I'll have a pretty firm grip on the bars. I doubt it.

I lean the bike into the turn more than my body on tight slower turns and undoubtedly countersteer, but for high speed turns, I lean my body first. I don't think one turns the wheel in the direction of the turn at speed, either. I think the bike turns the wheel without assistance due to front geometry, just like when one tries to push over a bike rolling by itself. Definitely no countersteer in that case same as when rolling the bike holding the saddle. One simply leans the bike in the direction of the turn and the front wheel drops into it. I think the difference with a rider aboard is that the rider is much heavier than the bike and there's a hinge between rider and bike at the saddle.

I once had to take a friend out on my motorcycle and demonstrate 1-finger pulling on the opposite bar to convince him that's how a motorcycle turns. My motorcycle's too heavy to make it turn with bodyweight. I remember, when learning to ride that bike, that I discovered that I had to consciously countersteer to enter a corner nicely.

Trakhak

From the evidence of this thread and many earlier ones on the topic, it would appear that every motorcyclist believes that countersteering is essential to steer a bike but that many if not most non-motorcyclists here are puzzled by that assertion.

Jeff Neese

Ok. Let's ask the same question, without any math.

Q: How much weight would need to be added or subtracted from the rim of each 622mm bicycle wheel in order to make a noticeable difference in handling?

A: The amount of weight that needs to be added or subtracted from the rim of each 622mm bicycle wheel in order to make a noticeable difference in handling can vary depending on a range of factors, including the weight and size of the rider, the terrain being ridden, and the rider's preferences.

That being said, as a general rule of thumb, it's often recommended to keep the weight of each wheel as low as possible while still maintaining durability and performance. For most riders, a noticeable difference in handling could be felt with a change in wheel weight of around 100-200 grams or more, depending on the rider's sensitivity and the specific riding conditions.

For example, if a rider is using a set of wheels that weigh 1,500 grams per wheel and they were to replace them with a set of wheels that weigh 1,300 grams per wheel, they would likely notice a difference in handling, particularly in terms of acceleration and responsiveness.

Alternatively, if a rider wanted to add weight to their wheels for additional stability, they might add 100-200 grams of weight per wheel through the use of heavier rims or spokes. This would increase the rotational inertia of the wheels and could make the bike feel more stable at high speeds.

In general, any changes to wheel weight should be made with consideration to the overall balance and stability of the bike. Adding weight to the front or rear wheel can have a different effect on handling, and it's important to ensure that the bike remains stable and responsive under a variety of riding conditions.

Q: And would the same amount of weight added to or subtracted from the frame yield the same differences in handling?

A: No, the same amount of weight added to or subtracted from the frame would not yield the same differences in handling as adding or subtracting weight from the wheel rims. This is because the location of the weight on the bike can have different effects on handling.

Adding or subtracting weight from the frame will affect the overall weight distribution of the bike, which can have an impact on how the bike handles. For example, if a rider were to add 1 pound of weight to the frame of their bike, the bike would become slightly heavier overall, and the rider may notice a difference in how the bike feels when climbing hills or accelerating from a standstill. However, this would not have the same impact on handling as adding or subtracting 1 pound of weight from the wheel rims.

As we discussed earlier, adding weight to the wheel rims can affect the bike's rotational inertia and gyroscopic effect, which can have a more noticeable impact on handling. For example, adding weight to the wheel rims can make the bike feel less responsive when cornering or navigating technical terrain, whereas adding weight to the frame would not have this same effect.

Overall, the location of weight on the bike can have different effects on handling, and it's important to consider the overall balance and stability of the bike when making changes to weight distribution.


Pretty consistent with what some of us have been trying to explain to you and a couple others, and I couldn't have said it better myself. (Well, maybe I could, but it's a lot of typing.) And before you make the very predictable statement that OpenAI or Google or Wikipedia or any number of physics textbooks are wrong, which do you think is more likely - that they are wrong, or that YOU are?

I also think it's interesting that they predict a noticeable difference in handling, beginning with a difference in mass of as little as 100 grams. It does come with a caveat, that I described earlier, which is that it depends on the rider's sensitivity and the specific riding conditions. It's highly subjective and (it seems) depends more on experience more than anything else.

3alarmer 

...that thar is some physics, Bubba.

3alarmer 

...for my own edification, perhaps you could hold forth on the PeteHski approved definition of trolling. I am, like everyone else in the thread, here to learn.

3alarmer 

...did you want to add, "Bless your heart," ?

livedarklions

Cool story, bro. I'm sure their doctors were telling them to eat lots of pepperoni pizza, drink a milk shake every night and snort coke.

You're wrong thinking that you had anything to do with that, or assuming that they'd still be alive if they stopped eating meat and/or sugar.
BTW, you realize most sports drinks are full of sugar, right?

You told this story to make us think your advice about electrolytes, sports drinks and cramping was more credible than a doctor's. This story has literally nothing to do with that.

tomato coupe

What is the source of these 'answers'?

3alarmer 

...yes, it's a reasonably small number. Which leads to a reasonably small result. The effect can be scaled to whatever magnitude includes "the set of all available bicycle wheels". You would prefer it be restricted to a smaller subset, of currently available bicycle road race wheels. There's no misunderstanding, there's simply a difference of opinion. And when confronted with that, and the simple idea that not all bike rides consist of the same set of circumstances, you prefer to once more say, "physics". I gave up trying to convince you on any other view of the problem long ago. If you keep on responding in this manner, is that what PeteHski means by "trolling" ?

I confess I no longer care, but as stated above, we are all here to learn.

Here's another analogy, which will probably also get criticized as opaque and indecipherable: If I tell you I can cure your compulsive gambling problem by telling you to only play the quarter slots, have I effectively cured your problem ?

PeteHski

bs

elcruxio

I've seen this Jess Neese schtick before.
Starts out as earnest, gets thumped, has his feelings hurt and tries to validate with numbers (ai text), gets thumped again and then turns to trolling (second ai text, wd40 mention etc.) in order to leave as a "winner". He's sure showing those too serious cyclists who can't take a joke.

It really is one of the saddest things on any forum.

PeteHski

Well the myth about the importance of rotating mass came from road racers, so 400g is a reasonable delta to work with. But you could double it if you like and the conclusions will remain the same. We could reasonably say that all performance road wheel sets lie between 1-2 kg.

3alarmer 

...don't be mean. It won't bother me, and it will reflect poorly on your own self image. My analogy is my analogy. If you don't like or cannot understand where it comes from, (the idea that the history of the calculus includes this whole intuitive idea of ignoring smaller and smaller quantities of change), I'm not really worried by it. There is a varied level of knowledge base in the participants here, and I have never claimed mine is greater in physics and math. Only that even I am smart enough to realize that when you multiply something by a factor of approximately 2, the differences between force to accelerate mass on the static portion of the package (which includes me), versus the force I need to exert to spin up that weight on the wheels, differs according to the slopes of a simple two line graph, as those lines diverge.

The argument, if there is one at all, seems to be where it is reasonable to cut off the far ends of those two lines.

And quite honestly, I'm not the first person to mention you can simply move on with your life and ignore what I'm saying. Again, I won't be offended. I do that al the time on teh Biekforooms. I've only returned to this thread because I was curious where it went, and it is colder than a well digger's belt buckle outside, so I'm kinda pruned out.

MikeWMass

The video does not change my mind.
Your last statement is sort of what I am trying to say.
When you turn no hands, the wheel turns about the steering axis to keep the contact patch under the center of gravity (physicists, if this is not exactly accurate, please don't flame me!)
You can do the same thing with your hands on the bars and initiate a turn by shifting your weight.
I am not prepared to say whether gyroscopic effect is what causes the movement about the steering axis,
I don't see how it can be countersteering, as there is nothing to put a force in that direction about the steering axis. Also, the effect of countersteer is to lean the bike, which is what you have done by shifting weight.
I am not equipped to provide a more rigorous explanation of my understanding, this is the best I can do.

Edit: I agree with Carbonfiberboy's post 662, I think we are saying the same thing

tomato coupe

I think this falls under the category of a self-fulfilling prophecy -- make an opaque statement and predict it will be criticized as opaque.

3alarmer 

...Source ? I first heard it from the car people, way back in the '50's or '60's. A lot of those discussions centered around "unsprung weight" versus weight on the chassis. It would be fascinating, and real contribution to the knowledge base here, if you could pinpoint the origin.

...yes. At last we agree on something. Now if only we could somehow come to terms on whether that represents the set of all bicycle users, or even a majority of them, that would be real progress. I get that you have dedicated your life's work to speed. There's nothing wrong with that, per se. I just think maybe that has narrowed your field of vision a little bit. And even that is not intended as a criticism, only as a suggestion. You can dedicate as much of your life to speed as you want to...make zero difference to me. (There's that zero difference thing again. )

3alarmer 

....I knew if I participated in this discussion long enough, something like this was bound to happen.

3alarmer 

...I'm not the guy who started that thread on how learning works, but I'm pretty sure this response will not promote learning.

Maelochs

By the way .... I reject the claim that lighter wheels "handle" differently. I have not found the weight of the wheels to be a help or hindrance when rounding corners. What I have said is that the Feel Like they accelerate more quickly .... and that that perceived quicker acceleration lasts for about two-tenths of a second (less for most but I am week) because it takes a tiny bit less force to get a tiny bit less mass to start rotating, but once the wheels are rolling ... and we have learned, some of us---the tiny differences in weight make no appreciable differences.

In my experience, swapping between three different wheel/tire combinations (ranging from treaded gravel tires on 2 kg rims down to slim, light 28s on 1400-gram 37-mm CF wheels) on the same bike, it was just the first few pedal strokes which feel harder. Turning didn't feel different at all.

Not sure what science would say about all this, but since I didn't measure anything, set up control standards, and used a very variable power source ..... not sure science is involved.

I still value my impressions .... but if I were to be, say, trying to win profession or Olympic-caliber pursuit races or win F1 races and not dying, I would definitely go with science instead of impressions.

I would definitely never go with AI-generated nonsense i didn't even understand.

It's sort of funny ... when all this started, I really thought that lighter wheels made a big difference, and that rotating mass was a big factor---possibly because I have been interested in auto racing where the issues of unsprung weight and rotating mass play a larger role because of the higher forces and masses involved. Sort of fun to learn something new ....