Disc brakes or not

[rangersac]

SO, I went with the TRP HY/RD Brakes, and finally got around to installing them. I had nightmares with the lever pull, with the levers almost touching the bars before they grab the pads.

So, cue lots of google searching and cursing thinking that I had done something wrong....nope, turns out that the HY/RD calipers are designed to work with the 11-sp road levers sets that have a longer cable pull than my 10sp lever set (the only 10sp levers they will work with are the Tiagra 4700, which has the same cable pull as the 11sp series)

So, off to youtube looking for hacks, searching on BNA etc. Anyway, I found a temporary fix, which was to just unscrew the pinchbolt from the top of the arm and attach it underneath instead, then route the cable under the arm instead of over it, and that gave me enough pull to stop the levers bottoming out.

In the meantime, I found a guy in the USA who sells a Short Pull version of the Actuator Arms, which are designed to work with the 10-sp levers that have the shorter cable pull. He should have stock again in about 3 weeks, and that will make the calipers produce the right amount of lever throw. If I ever go 11-sp, I just fit the original actuator arm.

I fitted a set of HY/RDs to some Ultegra 6603 levers a month ago. You are right, it was a complete pain in the posterior to do, but with good cable routing and by really ensuring there's no slack at the ferrule/ lever interfaces they work well.

[trailgumby]

Noticed last weekend that over half my road group now are all on disc brake bikes. Looks like I'd better get one.

That's a good reason to start riding by yourself.

[Mububban]

Noticed last weekend that over half my road group now are all on disc brake bikes. Looks like I'd better get one.

So far it's only me and a guy on a Cannondale Synapse with discs in my weekend group. We're both in the slow group fwiw
I don't think anybody in the faster groups have made the jump to discs yet.

[Defy The Odds]

Rim options are starting to thin out. Giant has killed rim Defy and Propel, I'm not expecting TCR rim to survive into the 2019 lineup which will mean the largest manufacturer no-longer sells rim carbon bikes (ignoring all the 2018 stock still available).

Honesty, this is goood news.

When I eventually upgrade my Defy I am looking forward to getting a disc braked version.

The difference in progressive braking power is stark, and that is probably an understatement. If you ride in any sort of traffic this is nothing but a plus in my books.

Also, your rims stay looking nice (no roughing up brake surface).

When sceptics have had some solid time on a disc brake bike (hydro) eventually people will adapt to change

[Tim]

When sceptics have had some solid time on a disc brake bike (hydro) eventually people will adapt to change

I've had three years on a Defy Adv Pro with hydraulic discs.
I find the whole disc brake experience quite underwhelming. Yeah, it takes less effort to brake, ho hum. I can still slow down for corners just as well on the TCR.
There's no rim wear but I get better than 30K on rim braked wheels.
I've never overheated a rim or disc on long fast descents.
They're better in the wet, I rarely ride in the rain.
They squeal like a pig at times, the rim brakes don't.
For me, riding on uninterrupted country roads I'd rather the lighter weight, particularly in the front end of the conventional TCR than the heavy feeling steering and extra weight of the Defy.
I won't be in a hurry to buy a disc fitted bike again.
Just my impressions. I think everybody has drunk the marketing Koolaid.
One way or another it just doesn't make much difference to me.

[Defy The Odds]

When sceptics have had some solid time on a disc brake bike (hydro) eventually people will adapt to change

I've had three years on a Defy Adv Pro with hydraulic discs.
I find the whole disc brake experience quite underwhelming. Yeah, it takes less effort to brake, ho hum. I can still slow down for corners just as well on the TCR.
There's no rim wear but I get better than 30K on rim braked wheels.
I've never overheated a rim or disc on long fast descents.
They're better in the wet, I rarely ride in the rain.
They squeal like a pig at times, the rim brakes don't.
For me, riding on uninterrupted country roads I'd rather the lighter weight, particularly in the front end of the conventional TCR than the heavy feeling steering and extra weight of the Defy.
I won't be in a hurry to buy a disc fitted bike again.
Just my impressions. I think everybody has drunk the marketing Koolaid.
One way or another it just doesn't make much difference to me.

Marketing koolaid?

Sorry but i totally disagree.

Having ridden both bikes side by side i can tell you the progressive stopping power of proper ventilated discs is MUCH better than rim brakes.

Less stopping time means later braking means faster descents and cornering.... its also confidence inspiring in traffic if you have to brake suddenly.

Sounds like you need your discs adjusted or serviced

[Tim]

Having ridden both bikes side by side i can tell you the progressive stopping power of proper ventilated discs is MUCH better than rim brakes.

My DA9000 ( and even 105) rim calipers stop the bike and modulate brake application very nearly as well as the R685/785 discs.
The difference doesn't make a whole lotta difference.

Sounds like you need your discs adjusted or serviced

Nup. Meaty clean pads, straight and flat discs, perfectly functioning hydraulics.
The difference is appreciable but just not that important or mind-blowing TO ME. Not worth spending extra on.
I don't ride in city traffic and only in the rain if caught out. If I were a commuter maybe, for my riding no.

[Defy The Odds]

Having ridden both bikes side by side i can tell you the progressive stopping power of proper ventilated discs is MUCH better than rim brakes.

My DA9000 ( and even 105) rim calipers stop the bike and modulate brake application very nearly as well as the R685/785 discs.
The difference doesn't make a whole lotta difference.

Sounds like you need your discs adjusted or serviced

Nup. Meaty clean pads, straight and flat discs, perfectly functioning hydraulics.
The difference is appreciable but just not that important or mind-blowing TO ME. Not worth spending extra on.
I don't ride in city traffic and only in the rain if caught out. If I were a commuter maybe, for my riding no.

You dont have to commute to appreciate them.

If you ride on the road at all and ever had to brake suddenly this is where they really shine.

Modulation on rim brakes will never be anywhere near as discs. There is a reason Mountain bikes switched to discs long ago...

So no, its not just marketing.

I was a sceptic too until i bought a gravel bike which has discs and the difference is very noticable on the road.

Not sure why your brakes squeel... that sounds like they are glazed over... definately need to be looked at.

Im advocating discs because they are better in every way to rim brakes and these are the hard facts.

Unfortunately many people resist change

[Tim]

Anyway, the subject has been done to death.
There's nothing wrong with the brakes on any of my bikes.
I just think the benefits of discs have been over hyped, IMHO.
I'm not at all resistant to change. I've embraced the technological advances, but they don't make me go much faster than thirty years ago.

[madmacca]

When sceptics have had some solid time on a disc brake bike (hydro) eventually people will adapt to change

I've had three years on a Defy Adv Pro with hydraulic discs.
I find the whole disc brake experience quite underwhelming. Yeah, it takes less effort to brake, ho hum. I can still slow down for corners just as well on the TCR.
There's no rim wear but I get better than 30K on rim braked wheels.
I've never overheated a rim or disc on long fast descents.
They're better in the wet, I rarely ride in the rain.
They squeal like a pig at times, the rim brakes don't.
For me, riding on uninterrupted country roads I'd rather the lighter weight, particularly in the front end of the conventional TCR than the heavy feeling steering and extra weight of the Defy.
I won't be in a hurry to buy a disc fitted bike again.
Just my impressions. I think everybody has drunk the marketing Koolaid.
One way or another it just doesn't make much difference to me.

After doing a descent of Donna Buang in the middle of an unexpected thunderstorm (on rim brakes), I can say definitively that my next bike will have disc brakes. Your use case of rarely riding in the rain may be different.

[Defy The Odds]

They are not just better in the rain. If you have ridden rim and disc brakes back to back and jumped on the front brakes hard you will see the significant difference in stopping distance.

This is in the dry. In the wet this is just amplified as the gap is larger.

The disc brake "propaganda" has lots of merit if you take off your traditionalist glasses

[P!N20]

The disc brake "propaganda" has lots of merit if you take off your traditionalist glasses

Ahem. That's Retrogrouch to you.

[MichaelB]

Hi Tim,

Well I guess if you think rim brakes are better for you, fine by me.

I'll take exception to one point though ;

..
For me, riding on uninterrupted country roads I'd rather the lighter weight, particularly in the front end of the conventional TCR than the heavy feeling steering and extra weight of the Defy.
.....

The two bike you are comparing have very different geometry, so to label the difference in handling down to the discs is just wrong. The weight is as much a function of overall with the twop different models.

Now if both bikes were TCR's, then it's be no issue.

Meh, enjoy your ride, whatever it is

[kb]

After doing a descent of Donna Buang in the middle of an unexpected thunderstorm (on rim brakes), I can say definitively that my next bike will have disc brakes. Your use case of rarely riding in the rain may be different.

I’ve done that. The main issue wasn’t the long descent but the first few km where it’s steep and you have an hour’s worth of crap on your rims from not braking during the climb

[The Walrus]

I personally think that disc brakes are more effective, but we are all different and have our preferences. I’ve had them on my MTB for 7 years and as a result got them on a new FBR last year.

I just see it as the latest technology so if you’re buying a new bike, to me it makes sense to get the latest available, but don’t upgrade your bike just for disc brakes...unless you can and want to.

As many have said, ultimately get what you want and what makes you happy.

[Comedian]

Anyway, the subject has been done to death.
There's nothing wrong with the brakes on any of my bikes.
I just think the benefits of discs have been over hyped, IMHO.
I'm not at all resistant to change. I've embraced the technological advances, but they don't make me go much faster than thirty years ago.

That's what this thread and all the other disc brake ones are about. People who just can't bring themselves to accept that some people are quite happy with rim brakes. They refuse to accept that just because disc brakes are good on a mountain bike that a road bike is sufficiently different in so many ways that perhaps rim brakes might actually be OK to the point of offering some advantages for road bike users. They refuse to take on board that some people don't ride in the rain, or that their rim brakes might actually stop really well. Or that they don't wear wheels out. So - they just tell them they are wrong and that they'd be happier with discs.

I ride in traffic and had to do an emergency stop the other day. The location of my camera actually just captures my brake lever in the right of screen. I remember doing the stop because it wouldn't have been pretty if I didn't succeed. I also remember it because I actually felt the thunk of the rear wheel as it touched down once I'd washed off enough speed and that surprised me. It must have been just hovering off the road a tiny amount as it was so close to the maximum braking I could manage without going OTB. The camera showed me grabbing the brake and then modulating in to keep it all going right. I just can't see how disc brakes could give me any more stopping power or any better modulation than what I have now. But clearly I'm wrong.

On the other hand, I there is no way I'd ride my mountain bike without discs. But then I sit so much further back, have a dropper seat post to stop OTB happening. I've got shock absorbers to keep the front plush, plus I've got monster tyres to absorb all that energy. Plus.. I can't hear all the funny noises they make over all the other racket from riding in the bush. Oh.. last point is it weights 13kg so a little bit more weight isn't such an issue. How can that not be different?

[Mububban]

I just can't see how disc brakes could give me any more stopping power or any better modulation than what I have now. But clearly I'm wrong.

You're right, dry braking isn't that much different.

GCN have done some videos on rim vs disc brakes. The latest had a 70cm stopping distance advantage to the Dura-Ace discs over 105 rim brakes (jump to 10:15):




(edit - typo) On another test, SRAM Red disc vs SRAM Red rim brakes on carbon wheels, the discs were superior in anything rough or wet, but rated the same on a dry flat road (jump to 1:01):




I've chosen to delay N+1 for a couple of years. One of the reasons is so disc brake system weight can close the gap to rim brake weight, I'm hoping to get all the disc advantages with a much smaller weight penalty than currently, which is really the only negative in my opinion.

[Audioio]

I prefer discs but I'm a nervous rider!

I've read quite a few articles and forum threads debating this topic, including discussions of "torque". But one thing I've never seen mentioned is the linear speed of the braking surface. No matter where the brakes were located, angular speed will be the same, but linear speed is greater the further away from the centre of the wheel.

Let's say your wheels are doing 60 rpm. The speed at the outer edge of a 160mm disc is about 0.25 metres per second (based on the circumference of the disc), whereas the speed of a 700mm wheel is 2.2 metres per second. Of course, the breaking surface is a little way in, and the curvature of the braking surface would make a small difference too. Surely, the more-than-eight times increase in linear speed of the rim has to be a pretty large factor in determining which is better.

Or is my arithmetic faulty or of no consequence?

[MichaelB]

.... Surely, the more-than-eight times increase in linear speed of the rim has to be a pretty large factor in determining which is better.

Not faulty arithmetic, but there are many more factors that govern the actual retardation force (the bit that slows you down) that can be generated. Friction (pads to friction surface), force that can be applied between pads and friction surface are the two that really govern it all. They are the main two factors, as all others are technically the same for both systems (inertia, friction modifiers (water), road grip, tyre construction etc)

[bychosis]

I prefer discs but I'm a nervous rider!

I've read quite a few articles and forum threads debating this topic, including discussions of "torque". But one thing I've never seen mentioned is the linear speed of the braking surface. No matter where the brakes were located, angular speed will be the same, but linear speed is greater the further away from the centre of the wheel.

Let's say your wheels are doing 60 rpm. The speed at the outer edge of a 160mm disc is about 0.25 metres per second (based on the circumference of the disc), whereas the speed of a 700mm wheel is 2.2 metres per second. Of course, the breaking surface is a little way in, and the curvature of the braking surface would make a small difference too. Surely, the more-than-eight times increase in linear speed of the rim has to be a pretty large factor in determining which is better.

Or is my arithmetic faulty or of no consequence?

My understanding of physics agrees with you. More force is required at the disc brake to stop the wheel.

Having said that, my experience with disc brakes concludes that hydraulic discs are the better option for bicycle braking. That is not to say that rim brakes aren’t good, but just that I find disc brakes have multiple advantages.

[Jmuzz]

Surely, the more-than-eight times increase in linear speed of the rim has to be a pretty large factor in determining which is better.

Or is my arithmetic faulty or of no consequence?

It does generate more friction for the same pad size and pressure.
But that's unimportant since the pads generate more than enough friction on 160mm or even smaller.

Brakes work as energy converters, kinetic energy into heat energy.
Their limitation is dissipating the heat so they don't burn up. That's why Shimano do the Ice Tech cooling fins.
You can't make rim too hot since the rubber starts melting and in the case of composite rims the epoxy melts and structurally falls apart. You can make disc red hot (and race cars do).

You want the rotating mass (disc) as light and low radius as possible. But have to balance that with heat dissipation.

[Comedian]

Well I've managed to find someone who agrees with me!

Have a listen to the video review on this page. Just near the end he discusses the brakes. His summary is - the cycling industry is finding that the sweetspot tyre is a 25, and that normal rim brakes are more than adequate for a tyre of this size. He suggests to not bother with discs unless you are running bigger than 25 or of course a gravel bike.

https://cyclingtips.com/2018/04/campagn ... groupsets/

[MichaelB]

Well I've managed to find someone who agrees with me!

And ?

[Comedian]

Well I've managed to find someone who agrees with me!

And ?

Well according to you lot I'm totally off the planet. First there was specialized agreeing with me on fork compliance issues, and now cycling tips journos agreeing that rim brakes are probably a better compromise if you are running tyres up to 25's.

It appears to me that it's more of a difference of a road bike rider knowing how he wants his roadbike to be.. rather than the people in this thread who appear to me to be mountain bikers saying how they'd like their road bikes to be.

Despite what you might think I genuinely don't mind. I can see that perhaps people who ride MTB would like roadies with discs. I can see that people who ride in the rain a lot might like them from a rim wear perspective.

My arguments have always been that disc brakes offer very little for road bike performance. They increase weight and complexity, they reduce fork compliance. How do they help us? Well you've only got tiny little tyres so you aren't going to be able to use much of that brake force. If you're riding in a bunch you definitely aren't going to be able to use it unless you enjoy crashing with all your mates.

[cyclotaur]

Well I've managed to find someone who agrees with me!

And ?

Well according to you lot I'm totally off the planet. First there was specialized agreeing with me on fork compliance issues, and now cycling tips journos agreeing that rim brakes are probably a better compromise if you are running tyres up to 25's.

It appears to me that it's more of a difference of a road bike rider knowing how he wants his roadbike to be.. rather than the people in this thread who appear to me to be mountain bikers saying how they'd like their road bikes to be.

Despite what you might think I genuinely don't mind. I can see that perhaps people who ride MTB would like roadies with discs. I can see that people who ride in the rain a lot might like them from a rim wear perspective.

My arguments have always been that disc brakes offer very little for road bike performance. They increase weight and complexity, they reduce fork compliance. How do they help us? Well you've only got tiny little tyres so you aren't going to be able to use much of that brake force. If you're riding in a bunch you definitely aren't going to be able to use it unless you enjoy crashing with all your mates.

Living up to your forum name there - had a chuckle.