Discs, are they the DBs?

[simon.r]

Lawyer lips are compulsory. The pull out is worst with downward-facing dropout, if they open forward and down, at an angle, the potential danger is much less. Thru-axles solve the issue but mainly they are for rigidity with susforks. Have there been any actual cases of pull-out with disc brakes?

Back in 2003 (when discs were becoming popular on MTB's) the was a guy called James Annan who wrote about wheels pulling out on forks without "lawyer lips". I recall a fair amount of debate at the time, but I don't think I've seen more than a handful of reports of it happening since then.

My opinion is that a correctly used QR is fine with discs.

I have one bike with cheap discs (Pro-max callipers) and in the wet the braking performance is massively better than even top end rim brakes.

I'll be very surprised if duscs don't become almost universally adopted within the next few years, perhaps with some sort of guard for use in racing situations.

 

[raleighnut]

In August 2014 I was 2 metres off the back wheel of my mate rolling in to Taunton at about 20mph as some idiot coming the other way swerved to turn right, he hit the car square on and I missed it by a knats arse. He was lucky to get away with a free trip in an ambulance.

After that trip, I bought a Genesis Equilibrium Ltd Ed specifically because it had hybrid disc brakes (amongst other factors) maybe it's a confidence thing but I wouldn't be without them on the road. Once you get used to them they are better all rounders than rim brakes, less stress on your hands over repeated 100 mile days, better in the wet and they don't wear your wheels away (although they do require more manintenance)

If your a Sunday morning cyclist it won't matter as I agree, rim brakes in the dry, there isn't much in it but if your doing any distance or touring and exposed to different weather events I'd go with discs every time. As for the weight issue, cut out that second bacon roll, it'll compensate for the rotor weight.

I'll never go back (for a road bike)

S

For touring I'd use rim brakes every time simply for their ease of repair/spares availability. Braking effort/response - never had a problem with aluminium rims in 50yrs of cycling (Now steel rims in the wet ) although pad choice makes a difference (I like Clarkes pads)

For serious downhill MTB use discs are great but their level of 'faffiness' is something I can do without on road bikes.

 

[goody]

What was the question again?

 

[Yellow Saddle]

Have you ridden a road bike or mountain bike with hydraulic disc brakes?

You keep avoiding the question so i am assuming not

I am comparing rim brakes to disc brakes on a bicycle and the difference in their ability to brake, you stated disc brakes are not better than rim brakes

Assumption is the mother of all you-know-whats. I think the question is irrelevant, hence ignoring it. I'm trying to stay on the topic, giving you the facts as they stand. Whether I've ridden on them or not, it does not change the physics described here. If I say no, then you'll say "you see!". If I say yes, then you'll say "but those must have been crap ones then."

So, back to the issue. Do you understand the physics of braking on a two-wheeled vehicle where the CoG is higher than the hub or not? Laws of nature don't make exceptions for some of you out there although a few of you on here make such a claim. The Bible is full of such claims - some bloke can walk on water, another one has a nifty sardine and wine trick, another one managed to make the sun stand still in the sky until the cows eventually came home and yet another one took a ride on a horse with wings. Here there are people who claim they can skid their front wheels under the conditions mentioned, who have massively thin, fast puncture proof tyres and chains that last 10 000 kms on spit and ylang-ylang oil.

 

[Yellow Saddle]

For touring (Now steel rims in the wet )

Now that's fun.

 

[Yellow Saddle]

If you are commuting in all weathers with lots of stop start at traffic lights etc then you will wear through rims with calipers. Mine tend to last 18 to 24 months and my commute is only 20 mins each way. Whilst rims can be cheap, if you can't build a wheel yourself (which I can't) then labour to rebuild the wheel can be relatively high. I'm not sure if discs last longer but they are cheaper and easier to replace for the home mechanic.
I do notice braking is poorer in the wet on my rim brakes, by which I mean to achieve the same braking distance I have haul on the brakes really hard. Braking in the wet will always be poorer regardless of whether you use discs or rims as the traction between the tyre and road is reduced.
I get the impression that when people say the braking on disc brakes is better, what they mean is it is more consistent and less force is needed to achieve the same result. Some feel this is a benefit, others are less bothered and sight increased weight, reduced aero performance and higher complexity as downsides.
I'm about to purchase a disc equipped bike for commuting so will be able to comment better soon :-D

I think I'll print this and frame it.

 

[Yellow Saddle]

Back in 2003 (when discs were becoming popular on MTB's) the was a guy called James Annan who wrote about wheels pulling out on forks without "lawyer lips". I recall a fair amount of debate at the time, but I don't think I've seen more than a handful of reports of it happening since then.

My opinion is that a correctly used QR is fine with discs.

I have one bike with cheap discs (Pro-max callipers) and in the wet the braking performance is massively better than even top end rim brakes.

I'll be very surprised if duscs don't become almost universally adopted within the next few years, perhaps with some sort of guard for use in racing situations.

I remember him but I thought he was Allan. Nevertheless, the phenomena is well documented. It happened on forks without lawyers lips and only on wheels that where routinely removed and reset to nil each time. With braking on such a setup there is an ejection force on the wheel but properly tightened QRs easily resist it for a while, although there is some creep. The key is resetting and properly adjusting the QR. The problem is general user stupidity, or as someone far more politically-correct here once said, "mechanical unsympatheticness". QRs are on their way out with disc brakes not so much because the wheel ejects (which it doesn't with lawyers lips and good QR closure) but because some people manage to get the QR lever stuck in the disc at speed. Yes, you read right. They manage to get the QR lever stuck in the brake at speed. The industry panders to the lowest common denominator and the rest of us must suffer. Hence the trend to TA now.

 

[Kestevan]

I have a road bike with Ultegra rim brakes, and decent pads.
I have a road bike with RS505 Hydraulic disks.
I am not skinny, I live in a very hilly area, descend "confidently" and commute in all weathers.

In the dry, the rim brakes will stop me just as efficiently and quickly as the disk brakes. Any more efficiently and I'd be over the bars. Anyone who claims disk brakes are "stronger" or that they brake quicker whilst using them is talking arse.

However.... in the wet the disk doesn't have the same delay whilst the rim is cleared of water, doesn't suffer from the same level of performance degradation as the rim brakes; and is therefore "better".

The disk brake also requires less force to pull on hard. The level of pressure needed on a traditional rim brake to ensure and maintain full force application (especially in the wet) is much harder - especially for those with smaller hands/less grip strength (mrs kes for example). This is offset at least at least at present by the greater size of the hoods for hydraulic levers. Mrs Kes was recently in the market for a new bike and really did not like the hydraulic levers - even though she preferred the reduction in pull strength.

Disk brakes also don't trash your rims - I go through a set of rims every 18 months or so commuting. disks win here for me. On the other hand they can be heavier, may not look traditional and the hydraulic maintenance is more daunting than traditional cable setup. Oh, and none of my "spare" wheels fit the disk bike.

Personally, on balance I'm a disk convert.... but it's certainly not clear cut.

 

[Yellow Saddle]

I have a road bike with Ultegra rim brakes, and decent pads.
I have a road bike with RS505 Hydraulic disks.
I am not skinny, I live in a very hilly area, descend "confidently" and commute in all weathers.

In the dry, the rim brakes will stop me just as efficiently and quickly as the disk brakes. Any more efficiently and I'd be over the bars. Anyone who claims disk brakes are "stronger" or that they brake quicker whilst using them is talking arse.

However.... in the wet the disk doesn't have the same delay whilst the rim is cleared of water, doesn't suffer from the same level of performance degradation as the rim brakes; and is therefore "better".

The disk brake also requires less force to pull on hard. The level of pressure needed on a traditional rim brake to ensure and maintain full force application (especially in the wet) is much harder - especially for those with smaller hands/less grip strength (mrs kes for example). This is offset at least at least at present by the greater size of the hoods for hydraulic levers. Mrs Kes was recently in the market for a new bike and really did not like the hydraulic levers - even though she preferred the reduction in pull strength.

Disk brakes also don't trash your rims - I go through a set of rims every 18 months or so commuting. disks win here for me. On the other hand they can be heavier, may not look traditional and the hydraulic maintenance is more daunting than traditional cable setup. Oh, and none of my "spare" wheels fit the disk bike.

Personally, on balance I'm a disk convert.... but it's certainly not clear cut.

Nice perspective. Interesting to note also that even though hydraulic discs pull easier, it isn't really an issue. Which of course makes sense since no-ne has ever complained they don't have enough strength to pull cabled rim brakes.

 

[Kestevan]

Nice perspective. Interesting to note also that even though hydraulic discs pull easier, it isn't really an issue. Which of course makes sense since no-ne has ever complained they don't have enough strength to pull cabled rim brakes.

Not entirely true. Mrs Kes has very small hands, she also suffers from severe excema which has considerably reduced her grip strength, especially her ability to apply a constant/repeated pressure (such as when descending v. steep twisty hills). She would have benefited from hydraulics, but was put off because the hood size/shape currently used for Shimano mechanical shifting/hydraulic brakes was too wide for comfort. In the past she has always preferred SRAM hoods because of the shape and reduced lever reach, but has now gone with the new Ultegra and seems happy so far,

 

[Wafer]

Nice perspective. Interesting to note also that even though hydraulic discs pull easier, it isn't really an issue. Which of course makes sense since no-ne has ever complained they don't have enough strength to pull cabled rim brakes.

High mileage cyclist I work near is a complete convert to discs partly because it's so much easier on his hands/wrists. He may not have an issue with the strength required as such, but he's finding discs a big improvement. So lets not assume it's something to be dismissed.

 

[Yellow Saddle]

High mileage cyclist I work near is a complete convert to discs partly because it's so much easier on his hands/wrists. He may not have an issue with the strength required as such, but he's finding discs a big improvement. So lets not assume it's something to be dismissed.

I suppose I got caught out using the word no-one. There will always be someone who benefits from this or that feature. Granted. But application force is hardly a problem for most of us.

 

[Wafer]

I wouldn't be so sure of that, I'm talking about a guy in his 50s who cycles a lot, not exactly uncommon in the cycling community!
He may not have had a particular problem with rim brakes, doesn't mean discs aren't better though.
The other main benefits he's spoken about are largely due to his commuting, the things others have already mentioned about better performance in the wet and not wrecking rims through the winter.

 

[User33236]

I realise I am not the average, for reasons I will mention below, but I would not be without disc brakes, and in particular hydraulic ones (one drop bar one flat bar), on my all weather commuting bikes as I can get more braking force for less input on the lever.

As a kid I injured one hand which, as a result, means to this day it only has 60% on the grip force of the other. Earlier this year I injured the opposite wrist which has resulted in a reduction in grip force to match than the 60% of optimum I have in the other hand. Hopefully this will improve over time and I'm lucky to have a vigorimeter in my desk drawer to keep and eye on progress .

Yes I can stop my road bike in the dry on rim brakes but get nowhere near doing an 'endo' on them. In the wet I will be a long way down the road by comparison.

 

[smutchin]

I suppose I got caught out using the word no-one. There will always be someone who benefits from this or that feature. Granted. But application force is hardly a problem for most of us.

It's the middle of the night, you're over 400km into a 600km audax. Air temperature is barely above freezing, it's raining, and you can hardly feel your fingers. And the route includes some fairly steep descents. It's definitely a benefit then. (This was me, last May.)

Admittedly, that is not a situation most riders will ever find themselves in.