So rim brakes on Carbon wheels are better ...

[MichaelB]

https://cyclingtips.com/2017/12/carbon-clincher-safety/

As dodgy as some of the testing methodology in this report is

Disc brakes FTW !!!

Now, just waiting for someone to drag the old usual disc brake failure articles up as well ..... You know who you are ...)

[Thoglette]

Nothing dodgy, the results are exactly as expected.

They even state so in the article blatant advertisement.

The motor input was simply a number that was able to bring the wheel up to a reasonable speed and input enough power to fail the rims in a short amount of time

I'd like to see that test done on the average car (or semitrailer), with forces and speeds scaled appropriately. Now that'd be fun.

[familyguy]

Who holds a brake on for 20 minutes??

[Comedian]

Who holds a brake on for 20 minutes??

Shhh... you'll get branded a troll too!

[Duck!]

There are probabaly some gumbies out there who brake drag for that long....

[biker jk]

Who holds a brake on for 20 minutes??

You don't need to brake continuously for 20 minutes to melt a carbon clincher rim. This comment from the article was interesting:

J Connell a day ago
I have worked for years in bike shops near the Alps and I have seen many brands of carbon clincher rims heat damaged. Often the client will report that she/he had used these rims without problems for thousands of kilometres, only for it to fail when he/she was on a cyclosportive or cycling holiday, ruining the trip. Sometimes the client is not used to descending and will drag the brakes excessively, or they will be stuck in a group that descends too slowly, forcing the rider to brake excessively. But even amongst expert descenders riding in competent groups there are still problems due to unexpected hard stops or decelerations. On open roads mid summer, one might be forced to brake violently due to a car full of tourists stoped for photos mid hairpin, or one might be forced to brake excessively when stuck behind an RV or farm vehicle through a series of tight turns. Few riders will have problems under perfect circumstances, but on the hottest day of the year, stuck behind a slow group or vehicle on a long descent, carbon clinchers just might try to kill you.
Certain brands are catastrophic, but even with some of the better carbon clinchers in the business (campag and zipp) you get inconsistent/diminished brake performance when the rims heat up and are never quite as confident as with a good pair of aluminum rims. If the client insists on deep section carbon, push them towards tubs for the mountains. If they are open to shallow clincher rims, push them towards alu.

[Comedian]

Now, just waiting for someone to drag the old usual disc brake failure articles up as well ..... You know who you are ...)

The fascinating thing about this forum is how loud and forceful the disc brake proponents are. If you're like me and you think that rim brakes work well for your applications then you're branded a troll. The author of this article did a poll and was surprised that there was nearly 40% of respondents who said they were happy with rim brakes and had no intention to switch. The best part is I didn't even know about this poll so didn't vote several times.

It would seem that perhaps I'm not quite as alone as it might seem. I've no doubt that exact percentages will vary - but while rim brakes offer weight, performance, cost, and maintenance advantages that there will be enough of a niche that they will live on.

https://twitter.com/angryasian/status/9 ... 2936471552

[human909]

The fascinating thing about this forum is how loud and forceful the disc brake proponents are.

Old vs new. It isn't just in bicycles....

The sellers of 'new' promote new to sell their products. The buyers of new are zealots who promote it to justify their own consumerism and expenditures.

The old. The others, often driven by nostalgia, luddism or sometimes just common sense of if it ain't broke don't fix it. Sometimes the new takes over, sometimes it doesn't.

In the world of roadies embracing the consumerism sporting aspects carbon has long taken over. Yet for bicycles for more practical purposes it seems to have not been loved. Metal bikes and rim brakes have stood the test of time.


I don't understand why you would want carbon rims unless you are at the bleeding edge of competitiveness. It is like selling a F1 engine to a consumer when it will only last you a week or so of use before you need a rebuild.

[Comedian]

Who holds a brake on for 20 minutes??

You don't need to brake continuously for 20 minutes to melt a carbon clincher rim. This comment from the article was interesting:

J Connell a day ago
I have worked for years in bike shops near the Alps and I have seen many brands of carbon clincher rims heat damaged. Often the client will report that she/he had used these rims without problems for thousands of kilometres, only for it to fail when he/she was on a cyclosportive or cycling holiday, ruining the trip. Sometimes the client is not used to descending and will drag the brakes excessively, or they will be stuck in a group that descends too slowly, forcing the rider to brake excessively. But even amongst expert descenders riding in competent groups there are still problems due to unexpected hard stops or decelerations. On open roads mid summer, one might be forced to brake violently due to a car full of tourists stoped for photos mid hairpin, or one might be forced to brake excessively when stuck behind an RV or farm vehicle through a series of tight turns. Few riders will have problems under perfect circumstances, but on the hottest day of the year, stuck behind a slow group or vehicle on a long descent, carbon clinchers just might try to kill you.
Certain brands are catastrophic, but even with some of the better carbon clinchers in the business (campag and zipp) you get inconsistent/diminished brake performance when the rims heat up and are never quite as confident as with a good pair of aluminum rims. If the client insists on deep section carbon, push them towards tubs for the mountains. If they are open to shallow clincher rims, push them towards alu.

You see.. this is my point. I've said continually.. that if I lived and rode in an environment that was often wet, or was very hilly then perhaps discs would make sense and I understand they would be well worth consideration. Wearing out rims or blowing them up like this would annoy me.

But I don't. I live in Brisbane. We have the highest number of sunny days of all Australian capitals.. If it rains.. or even if the roads are wet I'll not ride the roadie and ride a more utilitarian bike. I don't like cleaning the bike after. Also, we just don't have big hills here. I can get down the steepest hill I ride with carbon clinchers in either the wet or the dry. No problems.

If I switch to discs I'll have to throw away just everything I have. All the bikes, all the wheels, all the gropsets, everything. And perhaps what ever I buy now will turn out to be an "interim standard" and I'll have to throw it all out again in a few years. And even if I did do that I'd have to put up with bikes that are more expensive, heavier, and have higher maintenance costs and overhead.

If something changes and I take one of my bikes to Europe I'll pop a nice set of alloys in. In the meantime, switching to a disc bike is like the 95% of people who own a Prado because one day they might like to drive Fraser Island but never quite get there. And so they are stuck with their SUV which is slower and more cumbersome to drive and costs more to buy and run than the car they should be driving.

[g-boaf]

Who holds a brake on for 20 minutes??

You don't need to brake continuously for 20 minutes to melt a carbon clincher rim. This comment from the article was interesting:

J Connell a day ago
I have worked for years in bike shops near the Alps and I have seen many brands of carbon clincher rims heat damaged. Often the client will report that she/he had used these rims without problems for thousands of kilometres, only for it to fail when he/she was on a cyclosportive or cycling holiday, ruining the trip. Sometimes the client is not used to descending and will drag the brakes excessively, or they will be stuck in a group that descends too slowly, forcing the rider to brake excessively. But even amongst expert descenders riding in competent groups there are still problems due to unexpected hard stops or decelerations. On open roads mid summer, one might be forced to brake violently due to a car full of tourists stoped for photos mid hairpin, or one might be forced to brake excessively when stuck behind an RV or farm vehicle through a series of tight turns. Few riders will have problems under perfect circumstances, but on the hottest day of the year, stuck behind a slow group or vehicle on a long descent, carbon clinchers just might try to kill you.
Certain brands are catastrophic, but even with some of the better carbon clinchers in the business (campag and zipp) you get inconsistent/diminished brake performance when the rims heat up and are never quite as confident as with a good pair of aluminum rims. If the client insists on deep section carbon, push them towards tubs for the mountains. If they are open to shallow clincher rims, push them towards alu.

You see.. this is my point. I've said continually.. that if I lived and rode in an environment that was often wet, or was very hilly then perhaps discs would make sense and I understand they would be well worth consideration. Wearing out rims or blowing them up like this would annoy me.

But I don't. I live in Brisbane. We have the highest number of sunny days of all Australian capitals.. If it rains.. or even if the roads are wet I'll not ride the roadie and ride a more utilitarian bike. I don't like cleaning the bike after. Also, we just don't have big hills here. I can get down the steepest hill I ride with carbon clinchers in either the wet or the dry. No problems.

If I switch to discs I'll have to throw away just everything I have. All the bikes, all the wheels, all the gropsets, everything. And perhaps what ever I buy now will turn out to be an "interim standard" and I'll have to throw it all out again in a few years. And even if I did do that I'd have to put up with bikes that are more expensive, heavier, and have higher maintenance costs and overhead.

If something changes and I take one of my bikes to Europe I'll pop a nice set of alloys in. In the meantime, switching to a disc bike is like the 95% of people who own a Prado because one day they might like to drive Fraser Island but never quite get there. And so they are stuck with their SUV which is slower and more cumbersome to drive and costs more to buy and run than the car they should be driving.

Comedian- even in heavy rain and on very steep and long descents you still don't need disc brakes. Swisstop pads, Dura Ace brake calipers and alloy wheels do the job fine. I was riding in the worst conditions and had no problems with this combination.

[Thoglette]

I don't understand why you would want carbon rims unless

Want or need? There's lots of things I want that I don't need and are of dubious utility

I used to commute in a mid-engined car with track suspension, lumpy cam, non-standard fuel mix and noisy-but-oh-so-sticky tyres (Yoko A32R) so I've been inside that tent

[MichaelB]

At the end of the day, this was posted as a bit of fun and the fish bit.

Anyway, the only thing that this test proves is that One brand of wheels survives one VERY SPECIFI and non-realistic test better than a handful of others. On a sample of one. Oh, and it's paid for by the brand that won the test.

You can do a similar test with discs and have similar types of results that are just as meaningless. Yes, you can kill a set of carbon clinchers if you mistreat them, but the same goes for anything. It's just another marketing spin.

What I find interesting, is that it's a ballsy move publishing this info, highlighting the brands and almost being defamatory. Will be interesting to see how the brands respond.

And as mentioned many times before, if you are happy with what you have brake wise, GREAT !! I am, and so should you be

[Jawa]

Who holds a brake on for 20 minutes??

You don't need to brake continuously for 20 minutes to melt a carbon clincher rim. This comment from the article was interesting:

J Connell a day ago
I have worked for years in bike shops near the Alps and I have seen many brands of carbon clincher rims heat damaged.

That’s the other variable that needs to be discussed (and rarely is). He mentioned “years” but from what I know carbon rims even from 2-3 years ago are night and day to comparative 2017 models in terms of TG points, resins etc. Look at a rim/tyre blow out on vid YT and its from years ago but people will use that as their proof carbon rims are bad today.

.. oh, and discs are ugly

[mikgit]

I don't understand why you would want carbon rims unless

Want or need? There's lots of things I want that I don't need and are of dubious utility

I used to commute in a mid-engined car with track suspension, lumpy cam, non-standard fuel mix and noisy-but-oh-so-sticky tyres (Yoko A32R) so I've been inside that tent

haha, there's nothing like turning up to work with half the gravel that made the road pulled up and stuck to your tyres, 032R's ftw

[hamishm]

As dodgy as some of the testing methodology in this report is

Seems to me that most people claiming dodgy methodology just don't like the outcome. What's your beef exactly?

[g-boaf]

Who holds a brake on for 20 minutes??

You don't need to brake continuously for 20 minutes to melt a carbon clincher rim. This comment from the article was interesting:

J Connell a day ago
I have worked for years in bike shops near the Alps and I have seen many brands of carbon clincher rims heat damaged.

That’s the other variable that needs to be discussed (and rarely is). He mentioned “years” but from what I know carbon rims even from 2-3 years ago are night and day to comparative 2017 models in terms of TG points, resins etc. Look at a rim/tyre blow out on vid YT and its from years ago but people will use that as their proof carbon rims are bad today.

.. oh, and discs are ugly

Even after the most recent big tours in Europe (Pyrenees, Alps, Dolomites), there were certainly some carbon wheels coming back looking pretty bad. Mainly riders dragging the brakes rather than letting the bike roll and then hitting the brakes hard on the approach to the corner. I don't know what brand/models of wheels they were. Letting the bike roll generally resulted in 70+km/h in places (some people doing 90+km/h) so I guess some people don't like those sorts of speeds. Aside from that, there are other more basic reasons to use alloy wheels, like what happens if you need to change a wheel, what is the spare wheel going to be?

Despite all that talk of gloom, some of the quick riders were using carbon wheels without issue.

[Jawa]

You don't need to brake continuously for 20 minutes to melt a carbon clincher rim. This comment from the article was interesting:

J Connell a day ago
I have worked for years in bike shops near the Alps and I have seen many brands of carbon clincher rims heat damaged.

That’s the other variable that needs to be discussed (and rarely is). He mentioned “years” but from what I know carbon rims even from 2-3 years ago are night and day to comparative 2017 models in terms of TG points, resins etc. Look at a rim/tyre blow out on vid YT and its from years ago but people will use that as their proof carbon rims are bad today.

.. oh, and discs are ugly

Even after the most recent big tours in Europe (Pyrenees, Alps, Dolomites), there were certainly some carbon wheels coming back looking pretty bad. Mainly riders dragging the brakes rather than letting the bike roll and then hitting the brakes hard on the approach to the corner. I don't know what brand/models of wheels they were. Letting the bike roll generally resulted in 70+km/h in places (some people doing 90+km/h) so I guess some people don't like those sorts of speeds. Aside from that, there are other more basic reasons to use alloy wheels, like what happens if you need to change a wheel, what is the spare wheel going to be?

Despite all that talk of gloom, some of the quick riders were using carbon wheels without issue.

Technique in braking on carbon rims I think is the major cause for any perceived failures. Your right though dragging on alloy may be acceptable but you can’t take that same approach to carbon. But many do and are first cry foul when it all goes awry. Riders weight, again another variable. A 100kg bloke bombing down Hotham is of course going to add more stress to wheels and braking tracks than a 65kg featherweight. Of course the latte sipping weekend warriors won’t have bar of that!

[MichaelB]

As dodgy as some of the testing methodology in this report is

Seems to me that most people claiming dodgy methodology just don't like the outcome. What's your beef exactly?

I'll start with this list ...
- single test of each rim only (not enough samples to prove results accurately)
- same brake pad for all is not as per recommendation
- doesn't replicate real world braking (constant speed and constant load)
- test is paid for by the winner (no independence and or double blind)
- no measure of actual braking force achieved (i.e. the rim might not explode due to heat, but it might not slow you down either)
- no details of tyre size & pressure (this can have a big influence) EDIT : They used Conti GP4000 25C inflated to 100psi (which is a bit high for 25C's ?
- what was ambient temperature
etc

The fact that one brand did better than others, is really only an interesting fact.

[g-boaf]

Your right though dragging on alloy may be acceptable but you can’t take that same approach to carbon. But many do and are first cry foul when it all goes awry. Riders weight, again another variable. A 100kg bloke bombing down Hotham is of course going to add more stress to wheels and braking tracks than a 65kg featherweight. Of course the latte sipping weekend warriors won’t have bar of that!

You don't even do that with alloy wheels, ever - it is very dangerous. I'm about 60kg and I don't do that. It's a whole different world when you are going downhill for 20km or more at very high speed.

[MichaelB]

Your right though dragging on alloy may be acceptable but you can’t take that same approach to carbon. But many do and are first cry foul when it all goes awry. Riders weight, again another variable. A 100kg bloke bombing down Hotham is of course going to add more stress to wheels and braking tracks than a 65kg featherweight. Of course the latte sipping weekend warriors won’t have bar of that!

You don't even do that with alloy wheels, ever - it is very dangerous. I'm about 60kg and I don't do that. It's a whole different world when you are going downhill for 20km or more at very high speed.

You don't even do it with discs !!

[g-boaf]

Your right though dragging on alloy may be acceptable but you can’t take that same approach to carbon. But many do and are first cry foul when it all goes awry. Riders weight, again another variable. A 100kg bloke bombing down Hotham is of course going to add more stress to wheels and braking tracks than a 65kg featherweight. Of course the latte sipping weekend warriors won’t have bar of that!

You don't even do that with alloy wheels, ever - it is very dangerous. I'm about 60kg and I don't do that. It's a whole different world when you are going downhill for 20km or more at very high speed.

You don't even do it with discs !!

I've never used a bike with disc brakes, but I can imagine the consequences - not good. When I got my bikes, disc brake equipped road bikes were still quite uncommon.

[warthog1]

You see.. this is my point. I've said continually.. that if I lived and rode in an environment that was often wet, or was very hilly then perhaps discs would make sense and I understand they would be well worth consideration. Wearing out rims or blowing them up like this would annoy me.

But I don't. I live in Brisbane. We have the highest number of sunny days of all Australian capitals.. If it rains.. or even if the roads are wet I'll not ride the roadie and ride a more utilitarian bike. I don't like cleaning the bike after. Also, we just don't have big hills here. I can get down the steepest hill I ride with carbon clinchers in either the wet or the dry. No problems.

If I switch to discs I'll have to throw away just everything I have. All the bikes, all the wheels, all the gropsets, everything. And perhaps what ever I buy now will turn out to be an "interim standard" and I'll have to throw it all out again in a few years. And even if I did do that I'd have to put up with bikes that are more expensive, heavier, and have higher maintenance costs and overhead.

If something changes and I take one of my bikes to Europe I'll pop a nice set of alloys in. In the meantime, switching to a disc bike is like the 95% of people who own a Prado because one day they might like to drive Fraser Island but never quite get there. And so they are stuck with their SUV which is slower and more cumbersome to drive and costs more to buy and run than the car they should be driving.

Agreed. Pretty well sums it up for me too.
I do go offroad in my evil 4wd though. lol

[uart]

Seven to nine pounds (32 to 41 Newtons) of brake force at the levers is not exactly feathering the brakes though. That's close to full on brake application in my opinion (think braking both wheels). With most modern braking setups I'd think that would stop you in under 20 seconds in most circumstances, let alone 20 minutes. Unless of course you have a 1200 watt motor driving you forward.

Actually that level of braking is right up around the level required to lock up a wheel, which is probably why that had to use a weight of 135 pounds per wheel - just to allow the drive motor to maintain traction.

So obviously it's not a particularly "real world" test, at least not for most people. It was still impressive to see that rim survive though, no matter how unrealistic. Sure if I lived in the alps, and did a lot of descending with poor technique, then those rim would look pretty good to me.

BTW. My only other criticism of the video is that they didn't measure the power levels at the drive motor. They kept the speed constant throughout, but the coefficient of friction of the pads on rims was a wildcard here. Any rim that had a poorer friction at the brake surface was actually at an advantage here, as the power levels would have been lower for such a rim.

[djw47]

I have carbon rims with disc brakes. They look as clean and beautiful as the day I bought them. I don't need to concern myself with grinding huge chunks out of the rim when I brake heavily in the wet anymore which in itself is a huge bonus. From what I've read, delaminating carbon rims is fairly unlikely however carbon rims and rim brakes on a steep descent, wet or dry, doesn't fill me with coonfidence. I have no concerns ripping down Donna Buang, Baw Baw or Hotham at full throttle on the discs, knowing that the chances of anything failing are virtually nil.

[hamishm]

As dodgy as some of the testing methodology in this report is

Seems to me that most people claiming dodgy methodology just don't like the outcome. What's your beef exactly?

I'll start with this list ...
- single test of each rim only (not enough samples to prove results accurately)
- same brake pad for all is not as per recommendation
- doesn't replicate real world braking (constant speed and constant load)
- test is paid for by the winner (no independence and or double blind)
- no measure of actual braking force achieved (i.e. the rim might not explode due to heat, but it might not slow you down either)
- no details of tyre size & pressure (this can have a big influence) EDIT : They used Conti GP4000 25C inflated to 100psi (which is a bit high for 25C's ?
- what was ambient temperature
etc

A lot of that was discussed in the article and the comments. They only ran a single test because they paid for the rims themselves, rather than having it provided. They used the same brake pads because they were trying to minimise variables supposedly. etc. etc.

I didn't care about the differences between wheels - the interesting part and the point of the article was that all of them are rubbish.