Please don’t make this a rim vs disc bloodfest. Stage 17 won with rim brake

[MikeD]

Deleted.

[Lina]

The women's Olympic Road Race winner lives about 60km away from me and we train on the same roads in the same conditions. She has no sponsor commitments and picked a Scott Addict RC with discs. She is also quite light, so weight matters proportionally more for her. Why would I pick anything else for rides in the region here?

On this Banana guy from Australia – he is a conspiracy theorist and has a long history of assault allegations. I would not take him seriously on any topic.
https://steemit.com/durianrider/@michae ... d-a-rapist

https://jezebel.com/a-year-of-bananas-v ... 1788340075

She would be even faster with older Scott Addict with rim brakes. Lighter.

Scott Addict RC 15 with Ultegra Di2 in my country weights over 7.5 kgs without pedals and costs over 5000 euros.

Older Scott Addict RC with rim breaks and Ultegra mechanical is somewhere around 6.8kg .


800 grams weight difference is - A LOT.

So appeal to authority is fine when it supports your point of view, but when it goes against yours it's not? Surely an Olympic champion knows what they're doing. Especially if they're an amateur without sponsors that has to buy their own equipment.

And the older Addict isn't nearly as aero as the new one. Considering she was on the breakaway from km 0, I'd say that mattered much more than few hundred grams of weight.

[Alexbn921]

I don't see where 4 piston calipers are better than two. Please explain.

4 pistons spreads the force out more evenly and since you can balance the pads front to back they feel better. They also use larger pads that last longer.

Number of pistons and pad size have zero effect on total breaking power. The ratio of piston to master cylinder matters and can be achieved regardless of the number of pistons.

20mm of rotor size is about 20% power. That's why mountain bikes use 200mm and down hill racers are using 220.

Road bikes don't really need bigger than 160 as the demands are different. I would run 180 front if I could.

[iheartbianchi]

So appeal to authority is fine when it supports your point of view, but when it goes against yours it's not? Surely an Olympic champion knows what they're doing. Especially if they're an amateur without sponsors that has to buy their own equipment.

And the older Addict isn't nearly as aero as the new one. Considering she was on the breakaway from km 0, I'd say that mattered much more than few hundred grams of weight.

I think you were just trying to make a point, but just got to add (going along with my theme that what the pros do don't matter), aero and weight considerations for women are much different than for men given the difference in surface area, mass and bike sizes (on average).

A male trying to take gear lessons from a female pro, or vice versa, is inviting even more inaccuracies.

Kiesenhofer is 165cm and her race weight at the games was probably low 50s. She was probably riding a size 47 or so frame. Smaller riders mean you get less relative benefit from aero gear or position (compared to a bigger rider), but more benefit from lower weight compared to a bigger rider (assuming lower overall power). Braking is also a lot easier if you're lighter and smaller. She probably would have been better off on an aero, rim brake bike.

[TobinHatesYou]

So appeal to authority is fine when it supports your point of view, but when it goes against yours it's not? Surely an Olympic champion knows what they're doing. Especially if they're an amateur without sponsors that has to buy their own equipment.

And the older Addict isn't nearly as aero as the new one. Considering she was on the breakaway from km 0, I'd say that mattered much more than few hundred grams of weight.

I think you were just trying to make a point, but just got to add (going along with my theme that what the pros do don't matter), aero and weight considerations for women are much different than for men given the difference in surface area, mass and bike sizes (on average).

A male trying to take gear lessons from a female pro, or vice versa, is inviting even more inaccuracies.

Kiesenhofer is 165cm and her race weight at the games was probably low 50s. She was probably riding a size 47 or so frame. Smaller riders mean you get less relative benefit from aero gear or position (compared to a bigger rider), but more benefit from lower weight compared to a bigger rider (assuming lower overall power). Braking is also a lot easier if you're lighter and smaller. She probably would have been better off on an aero, rim brake bike.

You know... or she's paying for her own gear and consciously switched to a disc brake road bike because of some combination of the following and more:

1) She prefers disc brakes for where she trains in Austria
2) When you pay for your own equipment, spending a lot on a brand new rim-brake bike in 2020/21 is a poor investment.
3) She chooses all the right gear like SwissStop Disc RS pads and knows which rotors to use. No warping rotors, no rub, no squeals. She was using SRAM Centerline XR rotors with Shimano calipers because she knows her shit...Like I've been saying for years, the Centerline X/XRs are the best rotors on the market.

The never-disc crowd just needs to accept that disc is here to stay, they have advantages, people like them and move on with their own lives. They'll be much happier that way.

What we don't need is cveks having a meltdown and posting durianrider content.

[MoPho]

3) She chooses all the right gear like SwissStop Disc RS pads and knows which rotors to use. No warping rotors, no rub, no squeals. She was using SRAM Centerline XR rotors with Shimano calipers because she knows her shit...Like I've been saying for years, the Centerline X/XRs are the best rotors on the market.

I have to disagree with you a bit on that, I did not have a good experience using the SRAM Centerline X rotors with Shimano calipers, albeit it was with Shimano pads not the SwissStop.

[iheartbianchi]

You know... or she's paying for her own gear and consciously switched to a disc brake road bike because of some combination of the following and more:

1) She prefers disc brakes for where she trains in Austria
2) When you pay for your own equipment, spending a lot on a brand new rim-brake bike in 2020/21 is a poor investment.
3) She chooses all the right gear like SwissStop Disc RS pads and knows which rotors to use. No warping rotors, no rub, no squeals. She was using SRAM Centerline XR rotors with Shimano calipers because she knows her shit...Like I've been saying for years, the Centerline X/XRs are the best rotors on the market.

The never-disc crowd just needs to accept that disc is here to stay, they have advantages, people like them and move on with their own lives. They'll be much happier that way.

What we don't need is cveks having a meltdown and posting durianrider content.

I wasn't speaking as to whether or not she made a poor equipment choice. Given she lacks sponsors, of course it makes sense for her to spend her money on future technology and not technology like rim which is clearly on its way out. My point was, at her body size and weight, equipment choices are far less material than for a bigger rider. Bigger riders benefit more from disc and aero since there is more mass that needs to be concealed from the wind, and more mass that needs to be slowed down by braking. But she would have been fine with rim, and probably would have been fine not even having any rear brakes at all. Disc brakes at her weight are overkill. But again, she's a smallish female, and nothing she does has any bearing on anyone but the smallest male riders.

The durianrider tangent is indeed odd. I'm not one to engage in character assasination so I try to remain neutral re him.

[TobinHatesYou]

I wasn't speaking as to whether or not she made a poor equipment choice. Given she lacks sponsors, of course it makes sense for her to spend her money on future technology and not technology like rim which is clearly on its way out. My point was, at her body size and weight, equipment choices are far less material than for a bigger rider. Bigger riders benefit more from disc and aero since there is more mass that needs to be concealed from the wind, and more mass that needs to be slowed down by braking. But she would have been fine with rim, and probably would have been fine not even having any rear brakes at all. Disc brakes at her weight are overkill. But again, she's a smallish female, and nothing she does has any bearing on anyone but the smallest male riders.

As a lighter rider, I'm going to mostly disagree. I have a distinct disadvantage at any speed where aero matters because it scales with frontal area. A rider with 50% more mass than me doesn't punch a 50% large hole in the air. Equipment doesn't really change that. In fact being able to cover even more surface area with slick fabric or latex panels amplifies the inherent watt/FA advantages of the larger rider.

[iheartbianchi]

I wasn't speaking as to whether or not she made a poor equipment choice. Given she lacks sponsors, of course it makes sense for her to spend her money on future technology and not technology like rim which is clearly on its way out. My point was, at her body size and weight, equipment choices are far less material than for a bigger rider. Bigger riders benefit more from disc and aero since there is more mass that needs to be concealed from the wind, and more mass that needs to be slowed down by braking. But she would have been fine with rim, and probably would have been fine not even having any rear brakes at all. Disc brakes at her weight are overkill. But again, she's a smallish female, and nothing she does has any bearing on anyone but the smallest male riders.

As a lighter rider, I'm going to mostly disagree. I have a distinct disadvantage at any speed where aero matters because it scales with frontal area. A rider with 50% more mass than me doesn't punch a 50% large hole in the air. Equipment doesn't really change that. In fact being able to cover even more surface area with slick fabric or latex panels amplifies the inherent watt/FA advantages of the larger rider.

I don't think you actually disagree. I was typing off the cuff here so I may not have been clear. A smaller (who is lighter) rider will have less front area, and a smaller bike. They are already at an aero advantage due to smaller size. In other words, a larger rider with more front area from their body, and a larger bike, has a more pressing need to get into a very aero position, and can benefit more from aero position/technology. Aren't we saying the same thing?

[TobinHatesYou]

I don't think you actually disagree. I was typing off the cuff here so I may not have been clear. A smaller (who is lighter) rider will have less front area, and a smaller bike. They are already at an aero advantage due to smaller size. In other words, a larger rider with more front area from their body, and a larger bike, has a more pressing need to get into a very aero position, and can benefit more from aero position/technology. Aren't we saying the same thing?

I'm saying the contribution of the bike matters less to a larger rider. That's true of both light bikes and aero bikes. The most important aero equipment for a larger rider are what he/she wears.

[iheartbianchi]

My brain is fried lol. I need to sleep.

[tjvirden]

I wasn't speaking as to whether or not she made a poor equipment choice. Given she lacks sponsors, of course it makes sense for her to spend her money on future technology and not technology like rim which is clearly on its way out. My point was, at her body size and weight, equipment choices are far less material than for a bigger rider. Bigger riders benefit more from disc and aero since there is more mass that needs to be concealed from the wind, and more mass that needs to be slowed down by braking. But she would have been fine with rim, and probably would have been fine not even having any rear brakes at all. Disc brakes at her weight are overkill. But again, she's a smallish female, and nothing she does has any bearing on anyone but the smallest male riders.

The durianrider tangent is indeed odd. I'm not one to engage in character assasination so I try to remain neutral re him.

That's completely incorrect; for smaller riders - smaller mass or size (mainly "frontal area") that is - equipment choice matters more, because the equipment is a higher proportion of total mass or aero drag.

[iheartbianchi]

That's completely incorrect; for smaller riders - smaller mass or size (mainly "frontal area") that is - equipment choice matters more, because the equipment is a higher proportion of total mass or aero drag.

That's a very linear, basic (and flawed) way of looking at it, and certainly not how aerodynamics works. You have to consider the total drag forces relatively to forward momentum. This involves the drag coefficient.

If we are talking in terms of reducing the drag coefficient, the potential reduction in the drag coefficient achievable by a smaller rider will ALWAYS BE LESS than the drag coefficient achievable by a larger rider with larger total front area.

Percentage reduction is not that meaningful when you take the following example - Reducing your drag coefficient from say 0.5 to 0.4 (a 20% reduction) compared to reducing from 2.0 to 1.8 (a 10% reduction). The latter has half the reduction, but double the overall reduction in the drag coefficient. So while the percentage decrease may be greater for a smaller rider, they relative benefits achieved by a smaller percentage reduction is still greater for a larger rider.

In a real world example, it is far more meaningful to improve the aerodynamics of a large passenger airplane (in terms of energy efficiency and speed) than it is to improve the aerodynamics of a model airplane.

Edit: I hope we're not talking solely about the drag coefficient of a bicycle by itself in a wind tunnel. I am talking about the entire system. The rider, their position, their clothing, their helmet, their bike, their bike setup. All these can result in a larger net decrease in the drag coefficient of a larger rider than a smaller rider. A high drag coefficient results in a much higher power requirement to maintain the same speed than a low drag coefficient. Hence, larger riders need to be as aero as possible, whereas smaller riders who by default have lower drag coefficients aren't as dependent on marginal reductions in their overall drag coefficient. Percentages may sound nice, but a 50% reduction in a drag coefficient that nets you only a 0.1 decrease is of lesser meaning than a 10% reduction that can net you a 0.5 decrease.

[tjvirden]

That's completely incorrect; for smaller riders - smaller mass or size (mainly "frontal area") that is - equipment choice matters more, because the equipment is a higher proportion of total mass or aero drag.

That's a very linear, basic (and flawed) way of looking at it,.......

No, it's not flawed - it's correct. You're spouting rubbish, as usual.

[iheartbianchi]

That's completely incorrect; for smaller riders - smaller mass or size (mainly "frontal area") that is - equipment choice matters more, because the equipment is a higher proportion of total mass or aero drag.

That's a very linear, basic (and flawed) way of looking at it,.......

No, it's not flawed - it's correct. You're spouting rubbish, as usual.

What a childish response. Power requirements to maintain a given speed does not increase on a linear scale relative to drag (it scales upwards exponentially and dramatically at higher speeds relative to the CDA). If you have a higher CDA, you require a proportionately greater amount of power to maintain the same speed. There are countless aerodynamic studies that have tested this. This means a larger rider with a higher drag coefficient will require a proportionately larger amount of power to maintain the same speed than a smaller rider, which makes it even more critical for the larger rider to reduce their drag coefficient than a smaller rider, since the corresponding power requirement for any given speed will be substantially lower for the smaller rider.