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Search: Posts Made By: PeteHski
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02-19-23, 02:16 PM
Replies: 341
Views: 10,521
Posted By PeteHski

We were still struggling with F1 tyre modelling...

We were still struggling with F1 tyre modelling in the 2000s. Michelin were trying to develop a thermal tyre model we could use in our F1 simulator, but it was far from perfect. The rest of the car...
02-19-23, 06:18 AM
Replies: 341
Views: 10,521
Posted By PeteHski

Maybe we should move on to the aero vs MOI...

Maybe we should move on to the aero vs MOI effects of dead flies stuck to the wheel rims.
02-18-23, 07:24 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Agreed, that's a whole different discussion.

Agreed, that's a whole different discussion.
02-18-23, 07:10 PM
Replies: 341
Views: 10,521
Posted By PeteHski

I don't think the difference in this case is...

I don't think the difference in this case is significant enough for it to matter either way. At least with the physics it's easy enough to calculate some numbers - even if people are still in denial...
02-18-23, 06:56 PM
Replies: 341
Views: 10,521
Posted By PeteHski

The maths has been done:- ...

The maths has been done:-

https://www.youtube.com/watch?v=0QDnUkUaQfk
02-18-23, 06:54 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Uphill accelerations? You mean like accelerating...

Uphill accelerations? You mean like accelerating from 9 mph to maybe 11 mph over a couple of seconds? Really you should just give up on this line of thought.
02-18-23, 04:09 PM
Replies: 341
Views: 10,521
Posted By PeteHski

The only thing your real world example proves is...

The only thing your real world example proves is that you can still win on old equipment if you are a bit stronger than the guy on new equipment. If the average gradient was 7% then lighter wheels...
02-18-23, 03:39 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Well you've seen from the physics that the...

Well you've seen from the physics that the magnitude of the cyclical accel-decel is actually reduced with more rotational inertia. So however small that acceleration is, it is going to be even...
02-18-23, 12:49 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Sure, if you can save a kg in weight then you may...

Sure, if you can save a kg in weight then you may gain the best part of a minute on a 1 hour alpine climb for the same power. But the effect of reduced rotational inertia for your 30 sec attack...
02-18-23, 12:40 PM
Replies: 341
Views: 10,521
Posted By PeteHski

I have exactly the same issue here and even more...

I have exactly the same issue here and even more so on car forums. Having a background in engineering and vehicle dynamics can be pretty frustrating at times. But when I read something that is clear...
02-18-23, 12:25 PM
Replies: 341
Views: 10,521
Posted By PeteHski

How arrogant do you have to be to put your own...

How arrogant do you have to be to put your own subjective belief ahead of those guys at Swiss Side, Zipp, Best Bike Splits etc and people here with Physics, Maths and Engineering degrees? Maybe you...
02-18-23, 10:56 AM
Replies: 341
Views: 10,521
Posted By PeteHski

There is no more work required on the ďmodelĒ. It...

There is no more work required on the ďmodelĒ. It already includes wheel rotational inertia. You just donít like to hear the result that it isnít important - not even at peak acceleration in a...
02-18-23, 06:26 AM
Replies: 341
Views: 10,521
Posted By PeteHski

It doesn't help when you get bike reviewers...

It doesn't help when you get bike reviewers saying how they can "feel" the improved acceleration of lighter wheels, when they are just a few hundred grams lighter. Plus they often assume it's mainly...
02-17-23, 11:40 AM
Replies: 341
Views: 10,521
Posted By PeteHski

Interesting read on several counts. The...

Interesting read on several counts.

The acceleration comparison was interesting to show the effect of wheel rotational inertia on power:-

Full bore sprint acceleration from 40 kph at 0.13G...
02-16-23, 07:47 PM
Replies: 341
Views: 10,521
Posted By PeteHski

At least the chat bots are not yet claiming that...

At least the chat bots are not yet claiming that rotational mass is worth 10x static mass. Maybe they will when theyíve heard it stated enough times on BF.
02-16-23, 05:40 AM
Replies: 341
Views: 10,521
Posted By PeteHski

I don't think the observation that higher inertia...

I don't think the observation that higher inertia makes pedalling smoother was obvious to some people in this thread actually. As for muscle fatigue in this scenario, isn't it obvious that it would...
02-16-23, 05:25 AM
Replies: 341
Views: 10,521
Posted By PeteHski

The article was actually discussing what makes...

The article was actually discussing what makes riding easier both in the peloton AND on the climbs. I'm not disagreeing about your own personal choice as a recreational rider focusing on long climbs...
02-15-23, 08:40 PM
Replies: 341
Views: 10,521
Posted By PeteHski

That SwissSide article also has a neat...

That SwissSide article also has a neat representation of the micro speed variations during the pedal stroke. Note the swings are actually higher with lower rotational weight.
...
02-15-23, 08:28 PM
Replies: 341
Views: 10,521
Posted By PeteHski

I take it you didn't read the SwissSide article...

I take it you didn't read the SwissSide article then. Based on SwissSide's computer model, Ineos used aero wheels on almost every tour stage. Watching the tour these last few years, it's clear that...
02-15-23, 05:41 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Show us the physics equations to prove this...

Show us the physics equations to prove this nonsense or go home. You seem happy to critique mathematical models (which actually model wheel inertia) simply because they don’t agree with your...
02-15-23, 05:12 PM
Replies: 341
Views: 10,521
Posted By PeteHski

The pro peloton teams and their engineers...

The pro peloton teams and their engineers disagree. They routinely choose deeper section aero wheels for everything bar the most epic mountain stages. Even then they often run 35-45 mm aero rims.
02-15-23, 05:45 AM
Replies: 341
Views: 10,521
Posted By PeteHski

They are certainly entertaining. We get the same...

They are certainly entertaining. We get the same thing in motorsport too. I give you Carroll Smithís infamous book ďTune to winĒ. Alternative physics from the 1970s guaranteed to have any University...
02-14-23, 09:26 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Friends do say Iím quite good at explaining this...

Friends do say Iím quite good at explaining this kind of thing. Working in motorsport engineering for several decades has probably honed that skill. Iíve also developed a really good sense of what...
02-14-23, 08:30 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Yeah and my second to second speed variation on a...

Yeah and my second to second speed variation on a climb is typically 0-0.1 kph. Virtually nothing as far as changes in wheel rotational energy are concerned.
02-14-23, 07:54 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Maybe thatís why I tear my hair out on BF...

Maybe thatís why I tear my hair out on BF alternative physics discussions!
02-14-23, 07:52 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Yes you can very roughly approximate to double...

Yes you can very roughly approximate to double the mass during acceleration. But that is if 100% of the wheel mass is at the outer diameter. Obviously it will be somewhat less in practice.

While...
02-14-23, 01:15 PM
Replies: 341
Views: 10,521
Posted By PeteHski

So does anyone with a degree in engineering,...

So does anyone with a degree in engineering, physics or mathematics agree with the importance of "micro accelerations" during the pedal stroke or believe that wheel mass is equivalent to approx...
02-14-23, 12:07 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Mate, just buy some reasonably light 35-50 mm...

Mate, just buy some reasonably light 35-50 mm deep aero wheels with 20+ mm internal rims within your budget and ride with the knowledge that a few hundred grams isnít going to make any major...
02-14-23, 11:59 AM
Replies: 341
Views: 10,521
Posted By PeteHski

At this point Iím pretty sure they will continue...

At this point Iím pretty sure they will continue to believe in the importance of wheel rotational inertia regardless of any data or mathematical modelling.

What they woníte able to do is quantify...
02-13-23, 09:01 PM
Replies: 341
Views: 10,521
Posted By PeteHski

So about 5W saving on an average speed of 19 mph....

So about 5W saving on an average speed of 19 mph. What did you expect?
02-13-23, 08:50 PM
Replies: 341
Views: 10,521
Posted By PeteHski

I haven't looked at all his numbers in details,...

I haven't looked at all his numbers in details, but they seemed pretty reasonable to me. His explanation also fits in with actual Newtonian physics. Yours doesn't.
02-13-23, 08:44 PM
Replies: 341
Views: 10,521
Posted By PeteHski

FFS do you not understand that the micro...

FFS do you not understand that the micro deceleration is irrelevant? All other things being equal he would actually have a smoother pedal stroke with a higher rotational inertia (although that would...
02-13-23, 08:31 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Too low based on what exactly?

Too low based on what exactly?
02-13-23, 08:28 PM
Replies: 341
Views: 10,521
Posted By PeteHski

I can see you are stubbornly determined not to...

I can see you are stubbornly determined not to understand this. He isn't accelerating at all. He's merely maintaining a very low constant speed against the force of gravity. If you want to invent...
02-13-23, 06:32 PM
Replies: 341
Views: 10,521
Posted By PeteHski

You were actually arguing about the effect of...

You were actually arguing about the effect of rotational inertia above and beyond the effect of simple static mass. Hence your heavy water bottle vs heavy wheel climbing challenge.

Why don't...
02-13-23, 02:23 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Good article thanks, which puts it all into...

Good article thanks, which puts it all into perspective. Bicycles don't accelerate very much and even less so when climbing. Therefore changes in wheel inertia are negligible. But will some people...
02-13-23, 02:12 PM
Replies: 341
Views: 10,521
Posted By PeteHski

I'm not ignoring the laws of inertia at all. I'm...

I'm not ignoring the laws of inertia at all. I'm just saying that you can ignore wheel inertia when there is little or no acceleration involved e.g. steady state climb. For changes in inertia to...
02-13-23, 12:47 PM
Replies: 341
Views: 10,521
Posted By PeteHski

Your speed variation with this "pulsating" power...

Your speed variation with this "pulsating" power output is so minuscule when climbing that it really doesn't matter and it actually does cancel out anyway. Only on BF do people regularly dispute...
02-13-23, 10:46 AM
Replies: 341
Views: 10,521
Posted By PeteHski

Those micro-accelerations and decelerations...

Those micro-accelerations and decelerations simply cancel out unless you actually use your brakes. So they are irrelevant.
The only thing that does matter is the actual static mass of the wheels as...
02-13-23, 05:13 AM
Replies: 341
Views: 10,521
Posted By PeteHski

Do you brake very often when climbing 7%...

Do you brake very often when climbing 7% gradients? I know I donít.

The fact is that wheel inertia has little or no additional effect over and above the static mass of the wheels when climbing. ...
02-12-23, 11:34 AM
Replies: 341
Views: 10,521
Posted By PeteHski

What you say is in line with the physics. The...

What you say is in line with the physics. The heavier wheels really are ďpullingĒ you along with their inertia at high speed. When coasting they would carry their speed longer too. The downside of...
02-12-23, 10:40 AM
Replies: 341
Views: 10,521
Posted By PeteHski

The only time you truly lose the flywheel energy...

The only time you truly lose the flywheel energy is when actively braking. When coasting you are actually making use of that kinetic energy.

The only dumb thing is assuming that the people...
02-11-23, 06:48 AM
Replies: 341
Views: 10,521
Posted By PeteHski

I just take the middle ground with 35 mm 1477g...

I just take the middle ground with 35 mm 1477g aero wheels (DT Swiss ERC 1400). 22mm internal width (perfect profile for 28-30 mm tyres) and unaffected by crosswinds. Most of my local routes have...
02-08-23, 11:13 AM
Replies: 341
Views: 10,521
Posted By PeteHski

Good point. I only have first hand experience of...

Good point. I only have first hand experience of up to 35 mm wheels. I've ridden these in very windy conditions and they were fine.
02-08-23, 11:10 AM
Replies: 341
Views: 10,521
Posted By PeteHski

I think that info is outdated. I have a pair of...

I think that info is outdated. I have a pair of Giant carbon SLR rims that are 17 mm internal and indeed I can fit 32 mm tubeless tyres. But the profile looks like a mushroom and they squirm more...
02-08-23, 10:28 AM
Replies: 341
Views: 10,521
Posted By PeteHski

I agree that you will gain more from the aero,...

I agree that you will gain more from the aero, but I wouldn't buy any wheelset with 17 mm internal rims today. I would focus on tyre choice in the 28-30 mm wide range and get wheels with 20+ wide...
02-07-23, 07:43 AM
Replies: 341
Views: 10,521
Posted By PeteHski

My prediction is that they will say itís all a...

My prediction is that they will say itís all a lie/conspiracy by Big Bike and that they were really all riding re-labelled Vittoria tubulars. Looking at the photos, Ineos even went to the trouble of...
02-07-23, 07:27 AM
Replies: 341
Views: 10,521
Posted By PeteHski

Who is telling you that you need newer equipment?...

Who is telling you that you need newer equipment? I missed that if it happened.
02-07-23, 04:35 AM
Replies: 341
Views: 10,521
Posted By PeteHski

Below is a summary of what tyres actually won...

Below is a summary of what tyres actually won each stage of the 2022 TDF

https://www.cyclingnews.com/features/tour-de-france-2022-tech-trends-who-won-with-what/

More than half the stages were...
02-06-23, 01:20 PM
Replies: 341
Views: 10,521
Posted By PeteHski

This ^ is complete bs, but not surprising from...

This ^ is complete bs, but not surprising from this guy.
Showing results 1 to 50 of 52
 


 
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