Disc or not?

meanredspider

NitrousOxide wrote:

I'm a little surprised we have not seen off the peg bikes come with a disc fork for say a front Hylex hydraulic, with an "old school" rim brake at the rear.

My Volagi allows you to fit rim or disc brakes so you could do just that. I've gone down a lesser hybrid braking route by having a HyRd on the front and a BB7 on the rear as I rarely use the rear brake.

rubertoe

I see a guy on a surly yesterday, with rim brakes and discs, it was massive overkill and there were cables everywhere out of the front especialy with the bar end shifters he was running - massive mess.

tgotb

Jonny_Trousers wrote:

For me, rim brakes have always been fine, but then I've never tried braking on carbon rims in the wet. Nor have I ever thrown myself down an Alp.

In the mountains, I'd be far happier with well-set up rim brakes. For me, discs have a whole load of advantages, and I have them on 3 bikes, but for outright performance and dependability I'll take a well set-up rim brake.

ugo.santalucia

Jonny_Trousers wrote:

I do accept that they're the future. I've read enough articles by people in the know to be convinced. It does seem a bit of a mess if systems at the moment, however. Maybe UCI sanctioning will solve that.

For me, rim brakes have always been fine, but then I've never tried braking on carbon rims in the wet. Nor have I ever thrown myself down an Alp.

If I had the money to buy a really nice new frame I think I'd be holding off to see what a year or two brings.

What mess? Are the 32,000 different types of bottom brackets and steerer tapers not a mess?

There are only two standards of disc fixing: 6 bolts and centrelock
There are two standards of fork dropouts: QR or through axle
There are two standards of caliper: cable operated or hydraulic

It's all very simple...

jonny_trousers

ugo.santalucia wrote:

Jonny_Trousers wrote:

I do accept that they're the future. I've read enough articles by people in the know to be convinced. It does seem a bit of a mess if systems at the moment, however. Maybe UCI sanctioning will solve that.

For me, rim brakes have always been fine, but then I've never tried braking on carbon rims in the wet. Nor have I ever thrown myself down an Alp.

If I had the money to buy a really nice new frame I think I'd be holding off to see what a year or two brings.

What mess? Are the 32,000 different types of bottom brackets and steerer tapers not a mess?

There are only two standards of disc fixing: 6 bolts and centrelock
There are two standards of fork dropouts: QR or through axle
There are two standards of caliper: cable operated or hydraulic

It's all very simple...

For you, perhaps. For the non-technically minded person, like me, it can be pretty confusing. Isn't there a rear axle width thing too?

If you're saying there are several options, all of which will work fine, then that's good to know.

apreading

There is a standard disc rear axle - 135mm. As opposed to the 130mm for normal road bikes.

The only issue with the rear axle is that some odd-balls tried to create a 130mm rear disc axle. Hardly anyone did this, and those that did found that replacing hubs or wheels is a nightmare. I think anyone who did this had already or will soon change to the standard 135mm.

I have heard of some frames being made with 132.5mm rear spacing, so that either 130 or 135mm could fit, but I dont think this is common or necessary.

Sounds like Specialized have done something a bit odd with the Diverge - I think this may have 130mm rear axle but you can switch the dropout to use 135mm if you want.

I think the main reason why some manufacturers have dabbled with not using the 135mm standard is that if you have straight chainstays you can get heel strike on them. You need to have curved, concave chainstays to avoid this.

So, there is a standard, just about everyone uses it but a few quirky characters have played with an alternative which has not taken off.

jonny_trousers

apreading wrote:

There is a standard disc rear axle - 135mm. As opposed to the 130mm for normal road bikes.

The only issue with the rear axle is that some odd-balls tried to create a 130mm rear disc axle. Hardly anyone did this, and those that did found that replacing hubs or wheels is a nightmare. I think anyone who did this had already or will soon change to the standard 135mm.

I have heard of some frames being made with 132.5mm rear spacing, so that either 130 or 135mm could fit, but I dont think this is common or necessary.

Sounds like Specialized have done something a bit odd with the Diverge - I think this may have 130mm rear axle but you can switch the dropout to use 135mm if you want.

I think the main reason why some manufacturers have dabbled with not using the 135mm standard is that if you have straight chainstays you can get heel strike on them. You need to have curved, concave chainstays to avoid this.

So, there is a standard, just about everyone uses it but a few quirky characters have played with an alternative which has not taken off.

Thanks for clearing that up.

meanredspider

TGOTB wrote:

Jonny_Trousers wrote:

For me, rim brakes have always been fine, but then I've never tried braking on carbon rims in the wet. Nor have I ever thrown myself down an Alp.

In the mountains, I'd be far happier with well-set up rim brakes. For me, discs have a whole load of advantages, and I have them on 3 bikes, but for outright performance and dependability I'll take a well set-up rim brake.

That's the most bizarre thing I've read in a long time. I believe, also, that it flies in the face of accepted wisdom. I'd love to hear why some rubber blocks squeezed against the edge of a rotating rim has better "outright performance and dependability" than the modern standard for all types of vehicular braking (and pretty much every other type of braking). What have you discovered that generations of engineers have missed?

tgotb

meanredspider wrote:

TGOTB wrote:

Jonny_Trousers wrote:

For me, rim brakes have always been fine, but then I've never tried braking on carbon rims in the wet. Nor have I ever thrown myself down an Alp.

In the mountains, I'd be far happier with well-set up rim brakes. For me, discs have a whole load of advantages, and I have them on 3 bikes, but for outright performance and dependability I'll take a well set-up rim brake.

That's the most bizarre thing I've read in a long time. I believe, also, that it flies in the face of accepted wisdom. I'd love to hear why some rubber blocks squeezed against the edge of a rotating rim has better "outright performance and dependability" than the modern standard for all types of vehicular braking (and pretty much every other type of braking). What have you discovered that generations of engineers have missed?

My logic is as follows:
1. Disc brakes on my commuting bike seem prone to the pads getting polished. Brake performance deteriorates to the point where they barely work, and then I have to take the pads out and sand them. Hopefully I'll get to the bottom of this problem, but as yet I haven't. I've experienced this issue with three different models of brake, and numerous pad manufacturers and materials.
2. Caliper brakes don't do this. They just work, and carry on working until the pads wear out.

Given the above, which would you take to the Alps for a week? When you're heading towards a hairpin at 80kph, would you rather have the brakes that are theoretically superior, or the ones you know will work?

And yes, you're probably going to give me some guff about bedding in the pads and then braking in the correct way to avoid polishing the pads. You may well have a point. However I have no interest in changing the way I ride, just to nurse a set of brakes which is supposed to be technically superior, but clearly isn't.

meanredspider

Well - all I can give you is some "guff" about the fact that you have a problem that none of the rest of the cycling community has yet you want to blame the equipment. It's an interesting position. And, yes, I'd happily hurl myself down a mountain (repeatedly, as it happens) at 80kmh (I've actually done it at nearly 100kmh previously) on disc brakes. In fact, I know I wouldn't have done the descents anything like as effectively on rim brakes judging by the number of people I passed in the braking zones - in the dry and even in the cool/cold parts of the day. With the temps in the 30's on the middle of the day, discs were in a different league as the rim braked bikes managed (or didn't judging by the "pops") the heat in the rims. Front tyre blow outs must be exciting as you approach a hairpin surrounded by fellow cyclists and other traffic. And I haven't even touched on what rain would have been like. But carry on believing that rim brakes are more effective.

wgwarburton

apreading wrote:

There is a standard disc rear axle - 135mm. As opposed to the 130mm for normal road bikes.

The only issue with the rear axle is that some odd-balls tried to create a 130mm rear disc axle. Hardly anyone did this, and those that did found that replacing hubs or wheels is a nightmare. I think anyone who did this had already or will soon change to the standard 135mm.

I have heard of some frames being made with 132.5mm rear spacing, so that either 130 or 135mm could fit, but I dont think this is common or necessary.

Sounds like Specialized have done something a bit odd with the Diverge - I think this may have 130mm rear axle but you can switch the dropout to use 135mm if you want.

I think the main reason why some manufacturers have dabbled with not using the 135mm standard is that if you have straight chainstays you can get heel strike on them. You need to have curved, concave chainstays to avoid this.

So, there is a standard, just about everyone uses it but a few quirky characters have played with an alternative which has not taken off.

I've been cycling for forty years or so, I don't know how many bikes I've owned but currently have three on the road, one awaiting refurb and one frame hanging in the garage. One of these is a Brompton, the others are normal road bikes.

None of them have 135mm axle spacing, nor the "standard" 130mm for road bikes.

None of them have disc brakes either, of course, but I don't think that's a problem. Unless, of course, I can't get parts to maintain them because bike shops and manufacturers would rather sell me a new bike.

I don't particularly want to buy another bike but if I did, how long would it last? The current crop of road bikes seem pretty pricey to me but I don't get the impression that the current "standards" will still be standards for long...
Out of interest, how easy is it to service a disc brake caliper? Are parts for them readily available?
...and will it be easy to find them in ten years time? Twenty? Thirty?

Cheers,
W.

P.S. Might be off topic... Maybe the rants thread would be more appropriate? :-)

First.Aspect

WG, the days of servicable parts are over, don't you know? The only servicable part on a bike these days is the frame, which can be serviced by replacing things attached to it (providing you can find a replacement bb of course).

In seriousness, you can service discs to some extent by greasing, replacing pads, obviously, and o-rings in some cases. But essentially, once they are done, you replace them. The main replacement issues in n-years from now are going to be finding hose connections which match whatever levers you have invested in at the other end.

Discs overall are great for some applications, but increasingly I don't think they will ever be routine for road racing, particularly given the recent trend towards post mount brakes (of course lacking a single standard!!).

Some events (e.g. Paris Roubaix) will benefit, but I can't imagine Cav putting up with the aero disadvantage during a sprint, or Bertie putting up with the weight disadvantage on the Stelvio. However I can imagine rim hydraulics finding a place and I could imagine race organisers designating some races "disc only" due to heavy rain, for example.

If the UCI were intending to keep the 6.8kg minimum I might have a different view.

roger_merriman

TGOTB wrote:

meanredspider wrote:

TGOTB wrote:

Jonny_Trousers wrote:

For me, rim brakes have always been fine, but then I've never tried braking on carbon rims in the wet. Nor have I ever thrown myself down an Alp.

In the mountains, I'd be far happier with well-set up rim brakes. For me, discs have a whole load of advantages, and I have them on 3 bikes, but for outright performance and dependability I'll take a well set-up rim brake.

That's the most bizarre thing I've read in a long time. I believe, also, that it flies in the face of accepted wisdom. I'd love to hear why some rubber blocks squeezed against the edge of a rotating rim has better "outright performance and dependability" than the modern standard for all types of vehicular braking (and pretty much every other type of braking). What have you discovered that generations of engineers have missed?

My logic is as follows:
1. Disc brakes on my commuting bike seem prone to the pads getting polished. Brake performance deteriorates to the point where they barely work, and then I have to take the pads out and sand them. Hopefully I'll get to the bottom of this problem, but as yet I haven't. I've experienced this issue with three different models of brake, and numerous pad manufacturers and materials.
2. Caliper brakes don't do this. They just work, and carry on working until the pads wear out.

Given the above, which would you take to the Alps for a week? When you're heading towards a hairpin at 80kph, would you rather have the brakes that are theoretically superior, or the ones you know will work?

And yes, you're probably going to give me some guff about bedding in the pads and then braking in the correct way to avoid polishing the pads. You may well have a point. However I have no interest in changing the way I ride, just to nurse a set of brakes which is supposed to be technically superior, but clearly isn't.

1 have you changed the rota? My wife's bike ended up with a polished rota, which is a cheap fix.

2 calipers brakes need to be adjusted as they wear, or need new cables or just new pads, disks in my experience just work.

I've never bedded in pads but equally they have always just worked.

some hard braking in the Alps would improve rather than worsen disk brakes.

My experience when going down reasonably big lumps in the uk, is that roadies have a much harder time once the speed ramps up, braking for harepen bends looks any thing but controled!

elbowloh

meanredspider wrote:

Well - all I can give you is some "guff" about the fact that you have a problem that none of the rest of the cycling community has yet you want to blame the equipment. It's an interesting position. And, yes, I'd happily hurl myself down a mountain (repeatedly, as it happens) at 80kmh (I've actually done it at nearly 100kmh previously) on disc brakes. In fact, I know I wouldn't have done the descents anything like as effectively on rim brakes judging by the number of people I passed in the braking zones - in the dry and even in the cool/cold parts of the day. With the temps in the 30's on the middle of the day, discs were in a different league as the rim braked bikes managed (or didn't judging by the "pops") the heat in the rims. Front tyre blow outs must be exciting as you approach a hairpin surrounded by fellow cyclists and other traffic. And I haven't even touched on what rain would have been like. But carry on believing that rim brakes are more effective.

Sounds to me that TGOTB is saying it's an issue of trust rather than purely just braking ability.

He has personally had a few problems with discs, that he has not had with rim brakes. Therefore he puts more trust in his rim brakes and that would be his brake of choice on a big descent.

wgwarburton

Hi,
I think part of the problem is that, from my perspective at least, we are making progress in the wrong direction.

We have moved on quite a bit since the eighties. If you look at an eighties bike and compare it to a current model there have been quite a few changes and it seems there are more coming... so, step back a little- look again at that eighties bike again and ask yourself what needs to change. Where are the weak points?

Is the the gears? The Frame material? The brakes? The shifters? The stem? Are the wheels too strong and therefore heavy?

No. For commuting purposes, all might benefit from an incremental improvement, as long as is doesn't compromise reliability, maintainability and longevity but they all pretty much work OK. Maybe some have.

The weak point is the chain, and the wider drivetrain. That's the thing you need to keep oiling, adjusting and replacing as it wears out. What's needed is a longer-lasting chain that doesn't rely on constant lubrication and a clean environment and which doesn't destroy the chainring and sprockets as a result of wearing out.

So, does our nice new bike have a better chain? Does it b******! It's thinner, as are the sprockets it runs on, more expensive and wears out just as fast, if not faster. The only alternative I've seen is belt-drive, which is also not backwardly-compatible and has it's own compromises...

If this is progress, it's in the wrong direction. Bikes as toys (or sports equipment, if you prefer).

Cheers,
W.

Initialised

roger merriman wrote:

TGOTB wrote:

meanredspider wrote:

TGOTB wrote:

Jonny_Trousers wrote:

For me, rim brakes have always been fine, but then I've never tried braking on carbon rims in the wet. Nor have I ever thrown myself down an Alp.

In the mountains, I'd be far happier with well-set up rim brakes. For me, discs have a whole load of advantages, and I have them on 3 bikes, but for outright performance and dependability I'll take a well set-up rim brake.

That's the most bizarre thing I've read in a long time. I believe, also, that it flies in the face of accepted wisdom. I'd love to hear why some rubber blocks squeezed against the edge of a rotating rim has better "outright performance and dependability" than the modern standard for all types of vehicular braking (and pretty much every other type of braking). What have you discovered that generations of engineers have missed?

My logic is as follows:
1. Disc brakes on my commuting bike seem prone to the pads getting polished. Brake performance deteriorates to the point where they barely work, and then I have to take the pads out and sand them. Hopefully I'll get to the bottom of this problem, but as yet I haven't. I've experienced this issue with three different models of brake, and numerous pad manufacturers and materials.
2. Caliper brakes don't do this. They just work, and carry on working until the pads wear out.

Given the above, which would you take to the Alps for a week? When you're heading towards a hairpin at 80kph, would you rather have the brakes that are theoretically superior, or the ones you know will work?

And yes, you're probably going to give me some guff about bedding in the pads and then braking in the correct way to avoid polishing the pads. You may well have a point. However I have no interest in changing the way I ride, just to nurse a set of brakes which is supposed to be technically superior, but clearly isn't.

1 have you changed the rota? My wife's bike ended up with a polished rota, which is a cheap fix.

2 calipers brakes need to be adjusted as they wear, or need new cables or just new pads, disks in my experience just work.

I've never bedded in pads but equally they have always just worked.

some hard braking in the Alps would improve rather than worsen disk brakes.

My experience when going down reasonably big lumps in the uk, is that roadies have a much harder time once the speed ramps up, braking for harepen bends looks any thing but controled!

1: I noticed this when I first switched to discs, I changed how I clean the bike to avoid getting things like GT85 or chain clearer any where near the discs or calipers. But even if I did I'd notice it straight away and go through the motions to clean them up by doing the bedding in procedure. For a polished rotor wire wool and isopropyl works and is cheaper than a new rotor.

In case you find the standard bedding in procedure a tiresome chore here are some really fun ways to sand you discs, ride them in the wet, ride them in mud or dusty gravel, brake hard on a fast descent, emergency brake as the car/van/lorry/bus you are drafting slows down, take them off road, it doesn't have to be a MTB park, any off road trail will do.

2: That only really applies to cable based single pull disc brakes and applies equally to all forms of cable actuated brakes. Twin piston hydraulic brakes are self adjusting and automatically adjust as the pad wears out so you don't need to keep tightening the cable to compensate.

My reasoning behind getting disc brakes was that in heavy rain and sub-zero conditions it can take a wheel rotation or more before rim brakes (even really good ones like XTR Linear Pull) can take a full revolution of the wheel or more if your rim has iced up, before the braking starts making them unpredictable and inconsistent.

tgotb

elbowloh wrote:

He has personally had a few problems with discs, that he has not had with rim brakes. Therefore he puts more trust in his rim brakes and that would be his brake of choice on a big descent.

Exactly, thank you :-)

I'm never going to be *racing* down an Alpine descent, and I should imagine very few people on this forum ever will. For that reason, I don't really need the extra few percent of performance a disk setup might give me. What I do want is a system which will work predictably, 100% of the time; for me, calipers tick this box, but discs don't (yet). 99.5% of the time isn't enough; I'll always take a small drop in performance over a small drop in reliability. I've never had issues with overheating rims (never even made them more than slightly warm to the touch) and never had issues descending in the wet.

Of the bikes I ride regularly, 3 have disc brakes, 2 have caliper brakes, and one has no brakes at all. I'm not anti-discs, but I don't yet trust them enough to take them to the mountains.

Thanks for the suggestions, guys, will add them to the list of things to try.

ugo.santalucia

TGOTB wrote:

1. Disc brakes on my commuting bike seem prone to the pads getting polished. Brake performance deteriorates to the point where they barely work, and then I have to take the pads out and sand them. Hopefully I'll get to the bottom of this problem, but as yet I haven't. I've experienced this issue with three different models of brake, and numerous pad manufacturers and materials.
2. Caliper brakes don't do this. They just work, and carry on working until the pads wear out.

Given the above, which would you take to the Alps for a week? When you're heading towards a hairpin at 80kph, would you rather have the brakes that are theoretically superior, or the ones you know will work?

And yes, you're probably going to give me some guff about bedding in the pads and then braking in the correct way to avoid polishing the pads. You may well have a point. However I have no interest in changing the way I ride, just to nurse a set of brakes which is supposed to be technically superior, but clearly isn't.

I took my Fugio to the Alps for the first time in June... it was my first trip to Italy on discs in summer... didn't notice any deterioration... brakes did perform as well as usual

To be honest I have never experienced the problems you describe... the only time when pads feel weak is after washing the bike... but it's a matter of minutes before the original performance is restored