Cable operated disc brakes on road bikes?

curium

I had a trip over to evanscycles this afternoon to test ride two potential winter commuting bikes.

I rode a Cannondale Synapse 105 disc and a Cannondale CAADX Disc 105. Both had cable operated disc brakes.

My preferred choice was the Synapse as the rear caliper is mounted on the inside of the rear triangle allowing easy fitting of proper mudguards (this is a winter commute candidate).

I got on with both bikes size-wise and the shifting was slick enough but the brakes were RUBBISH!

This was the first time I had used a road bike with cable operated disc brakes and I came back mid test ride to get the mechanic to check that the brakes were set up correctly.

On neither bike could I lock the front wheel when in the drops and grabbing a handful. My 105 rim brakes easily manage this on my Cube.

The sales assistant admitted that this had been his experience also and said something about the ratio of cable pull on the STI-levers not being optimal - I'm not sure of the technicals...

When I asked him if I could upgrade the Synapse to the latest Shimano hydraulic brakes (at a later date) he pointed out that the internally routed cable for the rear caliper might not make this possible. He thought the best thing might be cable operated calipers with a mineral oil operated piston - apparently TRP do some.

So anyway, I left without a winter bike but I bought some SKS raceblade long mudguards for the road bike which I'll try and fit tomorrow to see me through the coming winter.

Is this the consensus opinion? Are cable operated disc brakes on road bikes a bit meh? The best thing I heard about them was that they won't get any worse in the rain so I'll be consistently underwhelmed

Ouija

They need bedding in.

I've never had disk brakes that didn't need a week of riding before they started throwing you over the handlebars. You need to lay down a layer of material on the disks before that happens (it's the layed down material on the disk bonding with it's counterpart in the pads that cause the friction.... otherwise your just rubbing smooth, non sticky, pads against and even smoother metal surface.... not exactly a recipe for friction).

pinarellokid

I ride with a lad who has a pinnacle road bike with cable brakes and he can outbrake me in all weather, I'd say the pads were not bed in or something

curium

Ouija wrote:

They need bedding in.

I've never had disk brakes that didn't need a week of riding before they started throwing you over the handlebars. You need to lay down a layer of material on the disks before that happens (it's the layed down material on the disk bonding with it's counterpart in the pads that cause the friction.... otherwise your just rubbing smooth, non sticky, pads against and even smoother metal surface.... not a recipe for friction).

pinarellokid wrote:

I ride with a lad who has a pinnacle road bike with cable brakes and he can outbrake me in all weather, I'd say the pads were not bed in or something

Can you guys state what brake levers and calipers are in use on the roads bike you say are able to offer superior braking to what I experienced?

I am quite willing (in fact desperate!) to believe that the situation I experienced could easily be improved once I took delivery of either of these bikes but every I speak to is either confirming my opinion or giving me hearsay.

I believe the Cannondales are pairing standard 105 shifters with Promax Render calipers.

lesfirth

Ouija wrote:

They need bedding in.

I've never had disk brakes that didn't need a week of riding before they started throwing you over the handlebars. You need to lay down a layer of material on the disks before that happens (it's the layed down material on the disk bonding with it's counterpart in the pads that cause the friction.... otherwise your just rubbing smooth, non sticky, pads against and even smoother metal surface.... not a recipe for friction).

I have not had a bike with discs but I have spent years fixing car brakes. I agree the pads may need to bed in and improve with a bit of use but the rest of the above is rubbish.

Ouija

lesfirth wrote:

but the rest of the above is rubbish.

What "rest"? I was simply explaining what the act of "bedding in" was. Or do you mean you believe "bedding in" involves something else happening other than coating the disks with pad material?

frisbee

Ouija wrote:

lesfirth wrote:

but the rest of the above is rubbish.

What "rest"? I was simply explaining what the act of "bedding in" was. Or do you mean you believe "bedding in" involves something else happening other than coating the disks with pad material?

Your explanation ties up with my understanding.

http://www.stoptech.com/technical-support/technical-white-papers/bed-in-theory-definitions-and-procedures/brake-pad-bed-in

ugo.santalucia

Ouija wrote:

They need bedding in.

I've never had disk brakes that didn't need a week of riding before they started throwing you over the handlebars. You need to lay down a layer of material on the disks before that happens (it's the layed down material on the disk bonding with it's counterpart in the pads that cause the friction.... otherwise your just rubbing smooth, non sticky, pads against and even smoother metal surface.... not exactly a recipe for friction).

This.

Disc brakes are NOT better than rim calipers, they are just more reliable in wet conditions and crucially they don't grind down your rims.
Considering in a clincher rim the brake track is structural, effectively every time you brake you are increasing the chances of your rim blowing up under the tyre pressure. Wear indicators go some way towards making you aware of the issue, but many folks ignore their existence altogether.
If you spend big money on wheels, it seems a bit of a waste to then sand them down with a brake pad, no? Although some on the internet seem to get infinite life out of a rim, the average is between 5 and 10 K miles if used all year round. My mileage falls somewhere between those two figures, so it's either disc brakes or new rims every year... no brainer for me

Ber Nard

curium wrote:

On neither bike could I lock the front wheel when in the drops and grabbing a handful. My 105 rim brakes easily manage this on my Cube.

On a bike intended to be ridden when the roads are wet, slippery and potentially icy, I'd consider that a bonus.

penguin_of_death

Rim brakes generally give more powerful braking for less weight in perfect conditions as the wheel is acting as a huge disk, but worn disks are cheap to replace, rims aren't and rubber pads wear quicker and cant grip as tightly as disk pads.
Additionally the rims are nearer the road and pick up more grime than the disks and an out of true wheel won't affect braking.
Their disadvantages are additional weight, the fact that they will need bedding in (about 40 stops is often quoted) and the pads can become contaminated as they are porous.

Regarding models the Avid BB5 road takes an age to get running well, though the BB7 road is much better. The Tektro Lyra claims to be for road levers, but seems to be slightly out. There are some good shimano ones and I have seen interesting reviews on Spyre who have a caliper with both pads moving

Jon_1976

Regarding the long lever throw, check the amount of clearance between disc and inboard/outboard pads with no lever pressure. Reducing this gap (usually outboard has more effect) will reduce lever throw. As mentioned, once the pads bed in they will improve.

cycleclinic

The Tektro brakes work well with shimano STI's and Campagnolo ergo's. Doen builds with both,braking is excellent. I'm with ugo on the brakes as I have killed DT Swiss rims in 3k miles just by riding them in foul weather all the time. This is the problem I have. I love my current rim brake winter bike but I know it is not that sensible now. Maybe I should get disc mounts brazed on like MTBer did in the 90's, most of those riders survived the experience.

the tektro spyre is best mechanical caliper out there bar non. I do not consider being able to lock the front wheel on tarmac a good thing. In fact I don't like off road either much prefer the wheels not locking as you stop quicker that way.

Bed the pads in and they will be awsome if properly set up.

ugo.santalucia

thecycleclinic wrote:

The Tektro brakes work well with shimano STI's and Campagnolo ergo's. .

I was led to believe the TRP Spyre and HyRD don't work well with Campagnolo Ergos...

earthvspace4XTuUWcX

I have TRP spyres with Campag Xenon levers and they work fine.

redjeepǃ

I have a Dirty Disco cross bike with Avid BB7 brakes and once they were set up correctly have been awesome! I'd heard other comments about the Tektro brakes being much less so.

harry-s

I swap between two road bikes on an almost daily basis, - one is set up with discs, the other with rims, and I'm meticulous about how I set them up. There's no comparison between the braking, the discs are superior in almost every department, - modulation, power, feel. The rim set up has dura ace brakes/Swissstop pads, the disc set up TRP HyRd, - I experimented a lot with BB7s on the disc before settling on the HyRd. I can't say I experienced problems with 'bedding in', - after about 20 stops they were good to go, and they weren't exactly bad out of the box.

lesfirth

lesfirth wrote:

Ouija wrote:

They need bedding in.

I've never had disk brakes that didn't need a week of riding before they started throwing you over the handlebars. You need to lay down a layer of material on the disks before that happens (it's the layed down material on the disk bonding with it's counterpart in the pads that cause the friction.... otherwise your just rubbing smooth, non sticky, pads against and even smoother metal surface.... not a recipe for friction).

I have not had a bike with discs but I have spent years fixing car brakes. I agree the pads may need to bed in and improve with a bit of use but the rest of the above is rubbish.

I withdraw the above post and apologise for any offence while I do some research to back up my opinion.

curium

With regards to being able to lock the front wheel up: This is purely to convey how weak the braking was - I like to know that this is possible, if not necessary.

There have been occasions where I have had to grab a handful of brake and raised the rear end, this was not possible on both the Cannondales I tested and I thought this was unacceptable for a supposedly superior brake set.

The comments posted so far have left me undecided. Many people seem to believe that both these bikes purely needed setting up properly and the pads/rotor bedding in. If that is the case then I really liked the Synapse and would of bought it right there! It's sad to think that a shop could allow its products to be set up so badly that a man with cash burning a hole in his pocket is persuaded against spending it! This was Evanscycles in Canary Wharf.

Still not been able to get the experience of anybody with a disc brake synapse which is what I was after to convince me that this would be a good buy. Surely someone on this board has one!

kingstonian

Harry-S wrote:

I swap between two road bikes on an almost daily basis, - one is set up with discs, the other with rims, and I'm meticulous about how I set them up. There's no comparison between the braking, the discs are superior in almost every department, - modulation, power, feel. The rim set up has dura ace brakes/Swissstop pads, the disc set up TRP HyRd, - I experimented a lot with BB7s on the disc before settling on the HyRd. I can't say I experienced problems with 'bedding in', - after about 20 stops they were good to go, and they weren't exactly bad out of the box.

Completely agree with everything in this post

cycleclinic

The only time I can lock up a front wheel with disc brakes is when on dirt. They modulate well enough to allow you not to lock up. IF you lock up the front wheel on tarmac at speed when it is wet and greasy a loss of control may result or the back rides up which is why I tend to avoid it although I managed it on my carbon rims on sunday in a race had no choice anchors got slammed on in front of me so I had to follow. Also the back riding up has alot to do with your weight ditribution, if your bike puts more weight on the rear then it will be more difficult. Stopping distance is the only way to test brakes on a known good surface.

Also disc brakes are easily comtinated if being set up by greasy hands, I have done it before and then have to swap the out the pads that would give a weak brake feeling as would poor set up. Bedding in real but again they should work well out of the box.

A disc brake synapse will brake as well as another disc brake bike with the same caliper and rotor sizes which is 160mm I believe.

Take the bike to a good shop as you are abviously not sure how to resolve the problem and let them help you. Disc brakes work, even BB5 but the tekto's sypres do better and yes ugo sypres and hy-rd brake caliper work just fine with ergo's so use them.

If you are going to solve your self do
1) set them up from scratch properly ensure the fixed pad is placed a hairs width from the disc (a bit of minor rubbing is allowed) then adjust the moving pad to get braking.
2) if braking is still weak sand down the pads and the disc and clean with disc brake cleaner
3) if they are still weak replace the pads remember to clean the disc throughly before you allow the new pads to make contact.

That what I would do if your bike came into the shop. Any other shop should do the same thing. There is nothing wrong with your bike. The problem is with caliper set up or contimated pads i.e easily solved. This is why roadies think disc don't work they try something with a set up issue and blame the braking system.

curium

thecycleclinic wrote:

The only time I can lock up a front wheel with disc brakes is when on dirt. They modulate well enough to allow you not to lock up. IF you lock up the front wheel on tarmac at speed when it is wet and greasy a loss of control may result or the back rides up which is why I tend to avoid it although I managed it on my carbon rims on sunday in a race had no choice anchors got slammed on in front of me so I had to follow. Also the back riding up has alot to do with your weight ditribution, if your bike puts more weight on the rear then it will be more difficult. Stopping distance is the only way to test brakes on a known good surface.

Also disc brakes are easily comtinated if being set up by greasy hands, I have done it before and then have to swap the out the pads that would give a weak brake feeling as would poor set up. Bedding in real but again they should work well out of the box.

A disc brake synapse will brake as well as another disc brake bike with the same caliper and rotor sizes which is 160mm I believe.

Take the bike to a good shop as you are abviously not sure how to resolve the problem and let them help you. Disc brakes work, even BB5 but the tekto's sypres do better and yes ugo sypres and hy-rd brake caliper work just fine with ergo's so use them.

If you are going to solve your self do
1) set them up from scratch properly ensure the fixed pad is placed a hairs width from the disc (a bit of minor rubbing is allowed) then adjust the moving pad to get braking.
2) if braking is still weak sand down the pads and the disc and clean with disc brake cleaner
3) if they are still weak replace the pads remember to clean the disc throughly before you allow the new pads to make contact.

That what I would do if your bike came into the shop. Any other shop should do the same thing. There is nothing wrong with your bike. The problem is with caliper set up or contimated pads i.e easily solved. This is why roadies think disc don't work they try something with a set up issue and blame the braking system.

You've not actually read the original post have you?

The bikes concerned were brand new ones I test rode with a view to purchasing from Evanscycles in Canary Wharf. I didn't purchase them because the cable-operated disc brakes produced less stopping power than my 105 rim brakes.

These were the first road bikes with cable-operated disc brakes I had ridden and so I posted here to find out if this is a normal experience or if something was obviously wrong. I'm still not clear on the answer - it wouldn't be the first time that a shop which is part of a national chain had insufficient knowledge and experience of the products they sell to set them up correctly for the customer but a surprising number of people here seem to be suggesting that it would be unreasonable to expect them to outperform my 105 rim brakes in the dry.

ugo.santalucia wrote:

Disc brakes are NOT better than rim calipers, they are just more reliable in wet conditions and crucially they don't grind down your rims.

Ber Nard wrote:

On a bike intended to be ridden when the roads are wet, slippery and potentially icy, I'd consider that [inability to lock up the front wheel] a bonus.

Penguin of Death wrote:

Rim brakes generally give more powerful braking for less weight in perfect conditions as the wheel is acting as a huge disk, but worn disks are cheap to replace, rims aren't and rubber pads wear quicker and cant grip as tightly as disk pads.

So now I'm wondering if I was incorrect to expect braking performance that was equal to that of 105 rim brakes in the dry and superior in the wet or if cable-operated disc brakes on road bikes are simply not a robust enough system.
What I mean by that statement is that there are so many variables involved in the system that all need to be optimised that if any of them are overlooked this results in worse braking performance than rim brakes in the dry!

Harry-S wrote:

I swap between two road bikes on an almost daily basis, - one is set up with discs, the other with rims, and I'm meticulous about how I set them up. There's no comparison between the braking, the discs are superior in almost every department, - modulation, power, feel. The rim set up has dura ace brakes/Swissstop pads, the disc set up TRP HyRd, - I experimented a lot with BB7s on the disc before settling on the HyRd. I can't say I experienced problems with 'bedding in', - after about 20 stops they were good to go, and they weren't exactly bad out of the box.

This is the cable operated caliper that then uses hydraulics to operate the pads?

Once again to clarify - when I mentioned be able to lock the front wheel up that was lazy terminology on my part. What I meant was that on my 105 brakes in the drops, in the dry, if I grab a handful of front brake I can produce enough stopping power that the back wheel rises off the ground and I risk going over the handlebars.
Neither of the Cannondale disc brakes managed to produce that amount of stopping power.

ugo.santalucia

I think you are overthinking the all matter.

Disc pads need bedding in, that's the case for your car's pads too. Once they are bedded in, which doesn't take long, they are as good as a good set of rim calipers in the dry and better in the wet... and that's all there is to it.
BB7, Hayes CX 5 and the TRP Spyre are all good calipers, don't know about lower end ones.... Years ago I had a set of Shimano R 505 which were less good

veronese68

What Ugo said. I think the people that complain that disc brakes are not as powerful as rim brakes have cheap or incorrectly set up disc brakes. Cheap or incorrectly set up rim brakes are not very good either.

cycleclinic

I did read the you orginal post and answered. The brakes need setting up properly, the pads need bedding in some disc brake calipers work better than others, Pad choice can also make a difference but all the ones commonly used are pretty good. Nothing wrong with disc brakes bikes, except when there is a setup propblem or contamination of the pads/discs.

You will find it easier to lock the front wheel with a caliper rim brake if the tyre are narrow (23mm) and at high pressure 110 psi than the typical disc brake bike with 25mm or 28mm tyres and lower pressures. That is the first comparison that may not be the same in your test.

Being able to lock up the front wheel and raise the back end is not how you judge the effective of a brake that is what we are trying to tell you over and over again. Overal stopping distance should be your judgement and you are assuming just because you can lock the front wheel you can stop sooner. Locking the front wheel is actually loosing control! Disc brake bike's give you more feel so while you may not be able to lock the front wheel your stopping distance is the same if not better because you don't have to be on and of the brakes so much to keep the rear wheel on the ground. That kind of braking increases your stopping distance as the rear wheel is not braking!!!!!!!

So take a well set up disc brake bike and a your current steed and brake from the same speed and measure the stopping distance, then repeat in the wet. You will find the result interesting.

Is that clear.

Even my wife bike with hydraulic R785 brakes and 160mm XTR rotors is not a bike where you can lock the front wheel easily. The lever come back nearly to bars before the wheel locks in other words you pull the lever and get a bit of braking, pull it more and get a bit more, pull it all the way back and it like a big anchor has been thrown out back. With good rim brake it's a bit more on and off with the braking.

Hell why do you think MTBer's gave up on rim brakes (and good V-brakes grab more effecivedly than any side pull caliper brake) because the braking is simply better in all situations when pads are not worn or contaminated.
The last MTB race I did was dry. I forgot to brake on one fast straight and I nearly ended up in a big beach tree at 25mph. I did get round the bend but only becuase disc brakes are so effective and allowed me to control the braking and avoid locking the front wheel until I wanted too and with both wheels locked I managed a two wheel drift round the bend avoiding the tree and carried on. If I had been on rim brakes (I still use them) I would have crashed badly probably.

meanredspider

I'm going to disagree with Ugo. Disc brakes are better, full stop. Rim brakes are a compromise in pretty much every aspect: your wheel is the size that it is, the pad material is dictated by not wanting to wear the rims out, the calipers have to reach around the tyre so can't be stiff, the brake tracks run in all the crap in the road and, when they wear out, the wheel is scrap, the heat from braking goes into the wheel and consequently then the tyre/inner etc etc Disc brakes, on the other hand, are effectively the state of the art of all forms of braking. The calipers can be ultra-stiff, you can choose braking material simply for its braking ability, you can tune the diameter and material of the disc and design it for the one purpose of braking and so on. I've thrown myself down alpine descents without the slightest worry about brake temperature (in contrast to those around me on rim brakes) and reached near 60mph with total confidence that the cable discs (BB7 in that case) will stop (85kg of) me in a controlled manner. Cheap crap brakes of either type will be cheap and crap.

Not every situation needs discs. My road bike here in NL has rim brakes. But then I hardly brake here and there are no hills. Lighter riders won't benefit from discs as much as bigger riders nor will people that only ride in the dry or with no significant slopes.

And, to add to the locking question, the brakes on my first car (a 1976 Ford Fiesta 1.1L) would lock the wheels - it's a rubbish measure of braking. My race car runs big 6-pot calipers on dinner plate discs - the benefit is that I can modulate their immense power without locking the wheels.

Cable discs like BB7 and the latest generations of TRP are very very good. You need a little bit of mechanical nouse to set them up and bed them in and then they are excellent and infinitely better than 105 rims.

Manc33

Cable disc brakes could possibly be less powerful than 105 side pull brakes.

Why not just get hydraulics? I remember having those on a heavy MTB and oh boy did it stop well, too well.

Never even tried a cable operated one. I thought they were more for keeping dirt away (like any disc brake is) than the power and if you wanted power, you got hydraulics.

The BB7 is apparently a far better cable disc brake than the BB5, in that the BB5 can give you endless problems whereas the BB7 never does. Source: Touring cyclist of 40 years. EDIT: And above posters.

Most powerful road brakes I ever used were some ancient center-pull "Weinmann" brakes (with standard Kool-Stop). Was always doing endo's on that bike. :oops: http://bmxmuseum.com/forsale/weinmann_blowup.jpg

cycleclinic

Rs685 STI's are not avilable yet and expensive, many bikes with this system are in short supply. R785 STI are for Di2 only and even more expenive but brilliant. The tektro syre is best mechanical disc brake, the BB7 is old hat now, heavier and not as slim creating problems with fitting mudguards sometimes. Manc33 it sound like you have not used road disc brakes yet.

Also brakes that try to throw you over the bars are useless as for good braking both wheels need to be in contact with the gorund. So a little less braking on the front is no bad thing your stopping distance will be less. Why is this such a difficult concept for roadies to get there head around. Even the XTR brakes (the M985's) on my rigid MTB don't throw me over the bars and I would not want them to, as the rear end lifting up on a -15% downhill would be rather dangerous to say the least. The same applies when going down a steep decent on the road.

If you lock your wheels you take longer to stop so folks stop judging brakes by how dangerous they are .i.e how easily the rear wheel lifts up.

rolf_f

Manc33 wrote:

Why not just get hydraulics? I remember having those on a heavy MTB and oh boy did it stop well, too well.

Why not just get hydraulics? Stopping too well would be a good reason!!

As for those Weinmanns? Are you mad?!!! I had them on an old Carlton I did up for a mate. I think I had Koolstop Salmons on it. I set it up so that it was almost impossible to get the straddle cable hooked on (ie minimum clearance) but the bendiness of the metal meant that you still needed the full range of lever movement (ie almost to the bars) to stop the bike. On a steep descent, it was barely possible to decelerate! They feel great in theory - beautifully and firmly sprung - just not so useful in actually stopping.

thecycleclinic wrote:

Hell why do you think MTBer's gave up on rim brakes (and good V-brakes grab more effecivedly than any side pull caliper brake) because the braking is simply better in all situations when pads are not worn or contaminated.

But of course, MTBs aren't road bikes. Disc brakes are a no brainer on mountain bikes. The advantages are far less conclusive for road bikes and are affected by more variables.

ugo.santalucia

Rolf F wrote:

But of course, MTBs aren't road bikes. Disc brakes are a no brainer on mountain bikes. The advantages are far less conclusive for road bikes and are affected by more variables.

Yeah, keep adding variables and try to solve the equation... while your peers face extinction all around you...

meanredspider

ugo.santalucia wrote:

Rolf F wrote:

But of course, MTBs aren't road bikes. Disc brakes are a no brainer on mountain bikes. The advantages are far less conclusive for road bikes and are affected by more variables.

Yeah, keep adding variables and try to solve the equation... while your peers face extinction all around you...

PMSL

Manc33

This has to be the costliest upgrade if you suddenly thought "I want to replace my rim brakes with disc brakes".

Why on earth don't they just make frames to accommodate both rim and disc?

For rim brakes its one hole in a fork. For disc brakes its two holes on the fork. They are nowhere near each other and wouldn't interfere with each other.

I wouldn't care about riding around with empty IS mounts, or empty rim caliper mounts. To upgrade to disc currently, I would need a whole new frame. Frame code numbers even determine it, calling them "disc framesets" and so on. :roll: