RIM BRAKE FRAMES = OBSOLETE!

[tarmackev]

MTB pro. What you'd call a privateer. Racng the top level with sponsors and money but not doing it full time.
The only "team" I was on was as a junior on BMW/Pro Flex. After that Santa Cruz and then Scott were my bike sponsors. The only road racing I've done was winning Mt Washington as a junior, some college crits, and some little races in Hawaii and Tahiti.

Different definition in the UK, we seem to have a ton of riders who are privateers racing with domestic pro's. Not too sure about the mountain bike scene over here at the top level. Taking nothing away from what you've done though. Anyone racing at that level is extremely fit and dedicated.

Professional status is defined by the licence.

I had a UCI pro license for 20 years.

Can't argue with that. Pro license is pro.

[tarmackev]

I don't ride discs much, I prefer rim brakes but properly set up disc brakes are definitely better in any weather conditions.

[Junior Varsity]

I train indoors when it’s raining, but I don’t have a choice when it rains on race day. Or if I bet wrong when the forecast says “20%” chance of rain. Rim brakes don’t have a place in my stable as I want to consolidate around wheels that work on my gravel bike in addition to my road bike. I sure as hell am not racing on a rim-brake bike in the rain.

So I've done some training and one race in rainy conditions the last couple of weeks. Some of the other guys were on discs, some were on rimbrakes. I was on rimbrakes. I noticed something curious with the discbrake riders. When something unexpected happens in front of people, some people tend to panic and pull the brake levers pretty hard. The disc users locked their rear wheel which resultet in a crash for them, and for those riding behind them. That was not the case for all of the rimbrake users. Some of them didn't crash, some did. But all the disc brake users crashed due to blocked rear wheel.

This was just my own observation from three crashes. Definitely not scientific. Usually I almost never see crashes. The guys I ride with don't crash much. But for some reason I've observed three crashes in 3-4 weeks.

But it made me think how safe discs actually are in comparison to rimbrakes, when braking while panicing.

User error rather than equipment problem I'd guess.....I know it's a generalisation, but most road riders rely on their fitness, not technical skills. Braking on a wet, slippery road is part of a riders skills......these riders obviously aren't particularly good on the skills side.

It happens in World Tour races too, so don't tell me those guys don't have skills.

I can say, with 110% confidence, that not all WorldTour riders are great bike handlers. None are 'bad' by any stretch of the imagination, but not all are great. What they all have are an ability to put out an insane amount of power beyond what most people can begin imagine. The best example I can provide comes from baseball, but the saying goes “difference between you and a MLB pitcher is the difference between throwing a bullet and firing one out of a gun”.

Back to the disc vs. rim conversation, the point of moving to disc is not just about braking performance (it's better, there is absolutely no dispute on that), it's about the bike’s overall performance. Caliper brakes limit the tire and external wheel width (which in turn limits the internal rim width). Wider (tubeless) tires at lower pressures with shorter contact patches improve Crr and comfort (less fatigue) , and significantly improve grip are all made possible by the additional clearance afforded by removing the caliper.

[blutto]

So I've done some training and one race in rainy conditions the last couple of weeks. Some of the other guys were on discs, some were on rimbrakes. I was on rimbrakes. I noticed something curious with the discbrake riders. When something unexpected happens in front of people, some people tend to panic and pull the brake levers pretty hard. The disc users locked their rear wheel which resultet in a crash for them, and for those riding behind them. That was not the case for all of the rimbrake users. Some of them didn't crash, some did. But all the disc brake users crashed due to blocked rear wheel.

This was just my own observation from three crashes. Definitely not scientific. Usually I almost never see crashes. The guys I ride with don't crash much. But for some reason I've observed three crashes in 3-4 weeks.

But it made me think how safe discs actually are in comparison to rimbrakes, when braking while panicing.

User error rather than equipment problem I'd guess.....I know it's a generalisation, but most road riders rely on their fitness, not technical skills. Braking on a wet, slippery road is part of a riders skills......these riders obviously aren't particularly good on the skills side.

It happens in World Tour races too, so don't tell me those guys don't have skills.

I can say, with 110% confidence, that not all WorldTour riders are great bike handlers. None are 'bad' by any stretch of the imagination, but not all are great. What they all have are an ability to put out an insane amount of power beyond what most people can begin imagine. The best example I can provide comes from baseball, but the saying goes “difference between you and a MLB pitcher is the difference between throwing a bullet and firing one out of a gun”.

Back to the disc vs. rim conversation, the point of moving to disc is not just about braking performance (it's better, there is absolutely no dispute on that), it's about the bike’s overall performance. Caliper brakes limit the tire and external wheel width (which in turn limits the internal rim width). Wider (tubeless) tires at lower pressures with shorter contact patches improve Crr and comfort (less fatigue) , and significantly improve grip are all made possible by the additional clearance afforded by removing the caliper.

....about that can't accommodate a bigger tire "problem "...well maybe they could simply also have gone back to the old standard larger caliper size that could accomodate larger tires ( these were replaced in the late 70's by much smaller assemblies and were mounted on shortened forks )....for a time both brake assembly sizes were available for most brands but eventually the larger size disappeared because they weren't the hip option the fashionable crowd needed to achieve maximum coolosity...and yeah the new small size also promised some ephemeral minimal, uhhh, marginal gains....

Cheers

[TobinHatesYou]

You're really throwing a lot of straw men into the mix.

I'm not saying discs are more dangerous. I'm saying there are situations, where the human factor can cause greater risk with discs than with rimbrakes. That means, that it doesn't apply to all situations.

The “because” in my statement already implies cause and effect, aka a situation and a reaction. Everything is situational. It is still an unreasonable assertion because panic braking will cause someone to go down on a wet road regardless of brake type. Panic braking is unlikely to be worse on a set of brakes that actually work with no latency and modulate better while wet. Aka if you’re panicking and your brakes aren’t working how you expect in the wet, you’re just going to squeeze even harder, then the water film will clear from the rim’s braketrack and all of a sudden you’re hit with more braking than the road surface can handle. So okay, you risk overshooting a corner or whatever AND going down because you lost grip on your front tire. Cool.

[blutto]

Disc brakes have great modulation. Panic braking by grabbing a fistful of brake is not advised on any kind of bike.

....so about that modulation thingee, here is a thought...up thread there is a comment about rim brakes having better modulation and of course disc brigade marched in and emphatically said no , because , like, everybody knows ( btw my fave squib comeback )....which got me thinking.....so here we have the disc brake mounted near the hub and it has to work thru the spokes to get to the thing that actually does the braking, the tire, and its mounted on a stiff frame section that is seriously damped because stiffness invariably produces much vibration, read the result is a noisy/crappy real-time feedback thru the frame....the rim brake is mounted right next to the tire, the final braking surface, and has a more immediate real time frame response because it doesn't have to deal the time-smear noise that damping and structurally wobbly spokes produce....

...so the question is....which system do you think will give you better feedback and allow better modulation ?....and remember, its the tires that ultimately stop you and modulating them is the way to the best braking performance...

Cheers

[TobinHatesYou]

You’re talking about about maybe 1mm of pad slop and torsional spoke deflection total on a wheel that is spinning at hundreds of RPM vs having to wait a few full rotations for all the water to be cleared off the braketrack in a wet braking situation, so what do you think?

Aka the difference in stopping distance due to that slop vs no slop is literally 1mm.

[blutto]

You’re talking about about maybe 1mm of pad slop and torsional spoke deflection total on a wheel that is spinning at hundreds of RPM vs having to wait a few full rotations for all the water to be cleared off the braketrack in a wet braking situation, so what do you think?

....that is really not what I'm referring to....its about having great modulation and not the stopping power....like did you even read my note and/or remember your post....

Cheers

[TobinHatesYou]

You’re talking about about maybe 1mm of pad slop and torsional spoke deflection total on a wheel that is spinning at hundreds of RPM vs having to wait a few full rotations for all the water to be cleared off the braketrack in a wet braking situation, so what do you think?

....that is really not what I'm referring to....

Cheers

But it is because it shows a properly tensioned spoked wheel isn’t as elastic as you think it is. We all know braking in dry conditions and on aluminum brake tracks is fine with a rim brake. We all know that wet braking with carbon rims is it’s one significant downfall.

And if you really want to get technical, we also know that rims deflect under a braking force and that rim brakepads compress/deform more. There is inherent vibration/judder thanks to that lower rigidity. But then again, some smoothing/suspension is actually good in scenarios with dynamic grip.

Still this is all academic nonsense because it’s pretty much undetectable by human senses. What matters is the big stuff we actually do notice like carbon braketracks being covered in a layer of lubricious water.

[Junior Varsity]

You’re talking about about maybe 1mm of pad slop and torsional spoke deflection total on a wheel that is spinning at hundreds of RPM vs having to wait a few full rotations for all the water to be cleared off the braketrack in a wet braking situation, so what do you think?

....that is really not what I'm referring to....

Cheers

But it is because it shows a properly tensioned spoked wheel isn’t as elastic as you think it is. We all know braking in dry conditions and on aluminum brake tracks is fine with a rim brake. We all know that wet braking with carbon rims is it’s one significant downfall.

And if you really want to get technical, we also know that braketracks deflect under a braking force and that rim brakepads compress/deform more. There is inherent vibration/judder thanks to that source of lower rigidity.

But then again, some filtering/smoothing is actually good. You want those extra layers of suspension to adapt to a dynamic grip situation whether it’s a poor quality road or a slippery surface.

This is all academic nonsense though because it’s pretty much undetectable by human senses. What matters is the big stuff like carbon braketracks being covered in a layer of lubricious water.

Let's not even get into the difference between the elongation of a wound cable vs. compression of brake fluid. But then again, I'm enjoying all of armchair engineering.

[TobinHatesYou]

Let's not even get into the difference between the elongation of a wound cable vs. compression of brake fluid.

[blutto]

You’re talking about about maybe 1mm of pad slop and torsional spoke deflection total on a wheel that is spinning at hundreds of RPM vs having to wait a few full rotations for all the water to be cleared off the braketrack in a wet braking situation, so what do you think?

....that is really not what I'm referring to....

Cheers

But it is because it shows a properly tensioned spoked wheel isn’t as elastic as you think it is. We all know braking in dry conditions and on aluminum brake tracks is fine with a rim brake. We all know that wet braking with carbon rims is it’s one significant downfall.

And if you really want to get technical, we also know that rims deflect under a braking force and that rim brakepads compress/deform more. There is inherent vibration/judder thanks to that lower rigidity. But then again, some smoothing/suspension is actually good in scenarios with dynamic grip.

Still this is all academic nonsense because it’s pretty much undetectable by human senses. What matters is the big stuff we actually do notice like carbon braketracks being covered in a layer of lubricious water.

....I wasn't talking about wheels but rather the deflection of a spoke when stressed across its longitudinal axis....as in how much resistance does a spoke exhibit when it is bent, as in very little...and then we have the deflection of those soft fat tires that are todays fashion favourite....and what this seems to add up to is a modern modulation mess....

....and btw successfully addressing those pretty much undetectable thingees is where we can separate great modulation from just grabbing a mitt of brake , you know like just looking at the big stuff like you suggest we do....

....and do please keep in mind that industrial design and engineering are applied science....read without that stuff you refer to as academic nonsense there wouldn't be much of a bike industry...the devil is often in the details eh...

Cheers

[Mr.Gib]

I just love that this is still going on. The fact that I find it entertaining probably makes me a bad person.

And so not to be left out... I did have an opportunity to test my carbon rim brake in proper rain and after a second of delay, the braking was very good, even excellent. Brake tracks were the grooved sort which is obviously the key. Had others in the distant past that were so terrifyingly bad you were better off using your feet Flintstone style. To be fair there is delay with discs as well when wet.

Yeah, they are obsolete. But then again so is my 5.7 litre V8 SUV.

[bobones]

Bobones definitely just claimed his rim brakes modulate better than his disc brakes and that they are a joy to use, especially in wet conditions.

Whether it amounts to superior modulation is hard to say, but I do really think my rim brakes give better tactile feedback at the lever, and they are a comparative joy to use in the wet because they don't do this:



That was more or less every time I braked this morning and it wasn't even raining properly. Dreich we call this typical Scottish weather. It can get much worse than that and there's the constant grating and scraping noises made when grit gets stuck on the wet rotors and pads. So in the very conditions discs are meant to excel and be so superior, they're actually a pain in the arse.

Don't tell me it's my setup because you hear the same on every cross race or wet road race now. Yes, resin pads can be quieter (not the scraping though), but they last me less than 100 miles in these conditions.

Oh, and that's another thing: you can't really see the wear on the pads without taking them out the calipers, whereas rim brakes are easy to eyeball before every ride. This is definitely another safety aspect in favour of rim brakes.

While we're on the subject of safety, I'd better not mention Richard Branson boiling his brakes coming down a mountain and almost killing himself because he's another one who can't ride a bike properly. Perhaps we should sit a test before being allowed on disc brakes given how easy it is to do it wrong.

Then there's the additional weight, the extra costs, undeniabley trickier maintenance, ... but , but, it's progress damnit!

Finally, I have 30 mm tyres WAM 32 on rim brake bikes, tubeless at low pressures, so I'm not missing anything there either!

[TobinHatesYou]

Nobody is saying that it is a tech issue. Disc brakes brake better than rim, and the modulation is better. Period.

Nobody eh?