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

Discuss light weight issues concerning road bikes & parts.

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stevesbike
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by stevesbike

Other than crashing, has anyone in the last decade 'worn out' their bike? Does anyone remember when Titanium frames were marketed as the last bike you'd ever need to buy? This entire thread has neglected the fact that today's bikes should outlast us all. The recourse of the industry is planned obselescence via new standards and technologies. Some of these, like electronic shifting, are decent improvements but disc brakes are questionable and only exist becuase manufacturers lobbied the UCI not to reduce the minimum weight. They offer nothing for nearly the entire consumer base.

openwheelracing
Posts: 308
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by openwheelracing

MikeD wrote:
Mon Aug 09, 2021 10:00 pm
Thanks to the UCI 6.8 kg weight limit...
I can't remember which podcast I heard this, but some teams are complaining about the 6.8kg limit cause it handicaps smaller climbers. Think Nairo, Simon brothers....etc. if they drop it down to 6.5 or 6.2 current gen disc brakes wouldn't be able to compete in weight.

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MikeD
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by MikeD

Although I don't see it anywhere, disc brakes probably killed Mavic Neutral Support, although they claim financial difficulties. It's probably not possible to provide wheels for every brand of disc brake along with the drivetrain system.

MikeD
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by MikeD

openwheelracing wrote:
MikeD wrote:
Mon Aug 09, 2021 10:00 pm
Thanks to the UCI 6.8 kg weight limit...
I can't remember which podcast I heard this, but some teams are complaining about the 6.8kg limit cause it handicaps smaller climbers. Think Nairo, Simon brothers....etc. if they drop it down to 6.5 or 6.2 current gen disc brakes wouldn't be able to compete in weight.
Yes. Some folks here argue that weight, in regards to disc brakes, doesn’t matter. Then why did bike frames go from steel, to aluminum, and now carbon fiber? It's because of weight or strength/weight.

openwheelracing
Posts: 308
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by openwheelracing

When Froomey switched to rim brake during TdF, I was hoping one of the media channels would do bike check between the disc he started with and the rim he ended up with. It never did happen of course. Someone at Cyclingtips said now each rider at ISN has two rim brake bikes.

MoPho
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by MoPho

MikeD wrote:
Tue Aug 10, 2021 2:14 am

Yes. Some folks here argue that weight, in regards to disc brakes, doesn’t matter. Then why did bike frames go from steel, to aluminum, and now carbon fiber? It's because of weight or strength/weight.

To get you to buy more stuff!




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spartacus
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by spartacus

If 1/2lb weight made a dam bit of difference and discs had no performance benefit then no professionals would use them. But they ride what their sponsors give them you say? Maybe up to a point, but they will not accept a performance disadvantage, and no company wants to provide them with a bike that's slower than someone else's. Honestly you guys that think 200g matters are out of control. I bet if the internet existed when STI shifters were invented we would have the same exact people making arguments for downtube shifters because they are lighter and blah blah it's just ridiculous at this point. Also I think rim brakes are perfectly fine. Honestly I don't think it matters much at all on a road bike.

blutto
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by blutto

Well, the 6.8 kg weight limit was a response to something.....a battle to create and use lighter and lighter bikes....a battle that followed the innovations that allowed the production of reliable aluminum and then carbon frames....but that battle got too close to the unreliable end of things and a limit had to be imposed to prevent a potential tragedy. And yeah things were getting to the ragged edge of reliability and people were willing to play on that edge....for those folks 200g did matter and kept mattering until that limit was imposed.

And then we have the founding idea behind Weight Weenies....a place where the weight of handlebar tape and bar end plugs matter....but oddly tubular wheelsets are not really in the frame though they are significantly lighter and pretty well eliminate the need for disc brakes....remember some folks say disc brakes on road bikes started simply to be a life support system for the continued sale of carbon clinchers ...

Just sayin' eh.

Cheers
Last edited by blutto on Tue Aug 10, 2021 4:49 am, edited 3 times in total.

MikeD
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by MikeD

200g seems too light. Just one 160 mm Dura Ace rotor without mounting hardware weighs 123g. Add in extra weight of the calipers, hubs, shifters, frame and fork, etc.

spdntrxi
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by spdntrxi

MikeD wrote:
Tue Aug 10, 2021 4:25 am
200g seems too light. Just one 160 mm Dura Ace rotor without mounting hardware weighs 123g. Add in extra weight of the calipers, hubs, shifters, frame and fork, etc.
win some here.. lose some there. I think 300g is more standard but it really depends.
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iheartbianchi
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by iheartbianchi

tomato wrote:
Mon Aug 09, 2021 9:54 pm
cveks wrote:
Mon Aug 09, 2021 9:47 pm
We rim brake lowers smoke disc brake lovers because rim brake bikes goes faster 5-10% for the same wattage/weight.
You really are dellusional. If rim brakes were 5-10% faster than disc brakes, there would not be a single pro rider using disc brakes.
Even if a rim bike in a wind tunnel is 5-10% faster, those are marginal gains and doesn't speak to "system gains." The frontal area of the rider, fitness levels, rolling resistance, aero position, bike fit, etc., are all so much more important than the bike. The bike is just a sideshow in our sport and something pretty to look at when we're not riding. But when you hit that first 10% climb on a ride, or your mate decides to hit an interval on a group ride, or a rider tryings a breakaway in a race...whatever bike you're on or whatever kit you're wearing goes out the window and none of it matters. Of course different story for the World Tour where tiny marginal differences may accumulate to make a big difference on a 5 hour racing day. But a bike will never decide who wins or loses in a 1 hour crit. So it's kind of silly for riders with FTPs below 4.0w/Kg to be beating ourselves over something that will have little to no impact on our lives.

It's like car maniacs arguing over whether a Ferrari is a better car than a Porsche. It doesn't matter, nobody but professionals can drive either of those cars to anything close to their limits. Most people couldn't even drive a Toyota to its limits. FWIW, I was at my fastest on a CAAD7 aluminum frame on mechanical 7sped dura-ace 20 or so years ago, and wasn't much slower than that on chromoly frames running 5-speed with downtube shifters, with ill-fitting clothes and crap shoes. I was wicked fast then and could fly uphill on 10-23 gearing, but I also weighed 53kg at 180cm then. Even with modern tech I am nowhere near those levels.
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Maddie
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by Maddie

MikeD wrote:
Tue Aug 10, 2021 4:25 am
200g seems too light. Just one 160 mm Dura Ace rotor without mounting hardware weighs 123g. Add in extra weight of the calipers, hubs, shifters, frame and fork, etc.
To clear another myth that every disc related part is heavier than their rim related counterpart:

Ultegra Di2 rim vs. Di2 disc
Shifters R8050: 295g / shifters R8070: 360g >> +65g
Calipers R8000 f/r incl brake pads and bolts: 341g / Calipers R8070 f/r incl 1x 160mm adapter, brake pads and all mounting hardware: 275g >> -66g
Shimano DA brake cable and housing (f/r) cut to length: 98g / Shimano brake hose (f/r) cut to length incl olives and mineral oil: 64g >> -34g
Ultegra brake discs 160mm / 140mm incl center lock rings: 246g

Rest of the bike:
DT Swiss 240 EXP straightpull 20 holes QR rim brake front hub: 102 g / DT Swiss 240 EXP straightpull 24 holes TA centerlock front hub: 104g >> +2g
Frames and forks weigh the same today, Colnago V3RS being an example.

Total: 213g more for a disc brake bike (211g from the groupset).

BTW: The mentioned 160mm DA rotor weighs 116g. 123g is with the centerlock ring.

tjvirden
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by tjvirden

iheartbianchi wrote:
Mon Aug 09, 2021 7:31 am
tjvirden wrote:
Sat Aug 07, 2021 10:03 am

From a design and manufacturing perspective, I don't see how a rim, for use with a rim brake, can offer those three things together: low weight, low drag and excellent braking wet or dry. What about the aero drag of the disc, I hear? Well, a rim caliper* with exposed cabling will roughly balance that........

*Edit: a standard, front-mounted caliper of course
The thing is though, the vast majority of recreational cyclists refuse to ride when it's wet outside. Just think about the cyclists in your region - how many are willing to go out for a ride when it's raining or rain is forecast?

For customers, the purchasing considerations are some combination of cool factor, low weight, aero, cost and reliability. Strangely enough, people will pay a premium for the cutting-edge benefits of lightweight and aero, but seem less interested in braking capability since nobody really wants to zip down a wet downhill at 80km/h where braking performance really matters b/c it's dangerous and nobody is being paid to put their lives at risk. In fact I'd dare say most recreational cyclists have never even gone 70km'h on their bikes, and maybe not even 60km/h, and you can't fault them for putting their safety first.
I'm certain the % who ride in the wet varies plenty!

Being based in Britain at the moment, it seems that there's no shortage of people riding in - literally - any conditions. It's true that many don't ride in "poor" conditions, but a lot do. It's similar in some other parts of Europe too. A constant low-level theme in the UK is the lack of mounts for full-coverage mudguards - but if a bike is 'designed' by someone who rides in California........well, perhaps it isn't surprising that they're not a significant consideration!

No doubt plenty of - perhaps most - recreational cyclists don't reach 'high' speeds, but quite a lot do; there are a lot of lucky people living in places with mountains and paved roads. I have personally seen many converts to disc because of bad (dangerous) experiences braking on carbon rims in the wet - that's just in the UK, which really isn't a mountainous place. However, a short 15 or 20% downhill in the wet (with no opportunity to warm a rim-brake rim up) switches most people over quickly - you're quite right that they shouldn't be faulted for putting their safety first.

tjvirden
Posts: 540
Joined: Sun Nov 22, 2020 9:21 pm

by tjvirden

stevesbike wrote:
Tue Aug 10, 2021 12:53 am
Other than crashing, has anyone in the last decade 'worn out' their bike? Does anyone remember when Titanium frames were marketed as the last bike you'd ever need to buy? This entire thread has neglected the fact that today's bikes should outlast us all. The recourse of the industry is planned obselescence via new standards and technologies. Some of these, like electronic shifting, are decent improvements but disc brakes are questionable and only exist becuase manufacturers lobbied the UCI not to reduce the minimum weight. They offer nothing for nearly the entire consumer base.
Hehe - they may not offer you anything of value, but lots of people want to be able to fit a wider range of tire sizes and have better braking in wet conditions and off-pavement. So they've been busily buying all the disc-brake bikes on offer.

Meanwhile, much of the time, I'm very happy riding with rim brakes........because they work wonderfully for the conditions I ride them in.

If the goal of the industry was "planned obselescence via new standards and technologies" then they've failed completely, because almost any bike can be brought into decent working order at modest cost......just have a look on Ebay..... :thumbup:

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Tifosiphil
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by Tifosiphil

tjvirden wrote:
Tue Aug 10, 2021 8:40 am
iheartbianchi wrote:
Mon Aug 09, 2021 7:31 am
tjvirden wrote:
Sat Aug 07, 2021 10:03 am

From a design and manufacturing perspective, I don't see how a rim, for use with a rim brake, can offer those three things together: low weight, low drag and excellent braking wet or dry. What about the aero drag of the disc, I hear? Well, a rim caliper* with exposed cabling will roughly balance that........

*Edit: a standard, front-mounted caliper of course
The thing is though, the vast majority of recreational cyclists refuse to ride when it's wet outside. Just think about the cyclists in your region - how many are willing to go out for a ride when it's raining or rain is forecast?

For customers, the purchasing considerations are some combination of cool factor, low weight, aero, cost and reliability. Strangely enough, people will pay a premium for the cutting-edge benefits of lightweight and aero, but seem less interested in braking capability since nobody really wants to zip down a wet downhill at 80km/h where braking performance really matters b/c it's dangerous and nobody is being paid to put their lives at risk. In fact I'd dare say most recreational cyclists have never even gone 70km'h on their bikes, and maybe not even 60km/h, and you can't fault them for putting their safety first.
I'm certain the % who ride in the wet varies plenty!

Being based in Britain at the moment, it seems that there's no shortage of people riding in - literally - any conditions. It's true that many don't ride in "poor" conditions, but a lot do. It's similar in some other parts of Europe too. A constant low-level theme in the UK is the lack of mounts for full-coverage mudguards - but if a bike is 'designed' by someone who rides in California........well, perhaps it isn't surprising that they're not a significant consideration!

No doubt plenty of - perhaps most - recreational cyclists don't reach 'high' speeds, but quite a lot do; there are a lot of lucky people living in places with mountains and paved roads. I have personally seen many converts to disc because of bad (dangerous) experiences braking on carbon rims in the wet - that's just in the UK, which really isn't a mountainous place. However, a short 15 or 20% downhill in the wet (with no opportunity to warm a rim-brake rim up) switches most people over quickly - you're quite right that they shouldn't be faulted for putting their safety first.
Riding in the UK has it's limitations, if I didn't ride in the rain I would barely be able to ride at all. 10 days into August so far and we have had maybe 3 days where it hasn't been raining at some point. Putting work and life into the mix and 80% of the time I've ridden this month it has either been raining or still wet on the floor

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