Cable disc and Cable Actuated 'Semi Hydraulic' Discs

[KneesUp]

I'm considering building up another bike, and the frame sets I've settled on all take disc brakes.

To quote Tom Lehrer fictionally quoting Nikolai Lobochevsky - Bozhe moi - this I know from nothing! I have bikes with cantilevers, v brakes, centre pulls and callipers, but have never owned or ridden a bike with discs.

The internets tell me that:

1) Cable discs are ok, but apart from Spyres, all have one piston which makes them a pain to set up and keep aligned and thus take a fair amount of fettling. The nest of the non-Spyre bunch seems to be Avid BB7s

2) Hydraulic discs are good, but you need large, ugly and expensive shifters and may or may not spend the rest of your days bleeding them - I guess this depends to a small extent on luck and a large extent to how well you set them up in the first place

3) Cable actuated hydraulics should overcome both these issues, but Hy:Rds seem to have attracted a large number of disgruntled posters who can't get them to work reliably. When working properly though they sound good - they have two pistons and auto adjust for pad wear. Juin Tech R1s are a closed system so they don't adjust for wear automatically, but they are cheaper and lighter then the Hy:Rds and seem to generally get better reviews.

Would this seem to be a fair summary?

I'm leaning toward the Juin Techs because I can use any old lever, they are relatively cheap and seem easier to live with then pure cable ones, and apparently have better modulation, but any input from anyone else would be much appreciated.

My other 'I've never used discs' before questions are:

1) How long do the pads last?
2) How long do the discs last?
3) How easy is it to change a wheel? I presume that if you have two wheelsets, the discs in theory should just line up (might have to adjust the pads a little for different amounts of wear, but this seems easy on the Juin Techs) but how does this work in practice?
4) Fade - I am about 75-80kg, and ride in reasonably hilly places, sometimes with panniers. I presume fade is not something I need to worry about unless I ride somewhere very hilly with very heavy panniers? Or can it occur in relatively 'mild' conditions?

Obviously the answers to all of these could be 'it depends' but entertain me

 

[Drago]

Cable discs do require fettling, but its not as regular as they'd have you think, and it's pith easy.

 

[Yellow Saddle]

1) Cable discs are ok, but apart from Spyres, all have one piston which makes them a pain to set up and keep aligned and thus take a fair amount of fettling. The nest of the non-Spyre bunch seems to be Avid BB7s

I don't know if they all have one piston, but any with two pistons rely on a hardware yoke to transmit tension to both sides and these yokes like to resonate and vibrate. Mechanical is a compromise.

2) Hydraulic discs are good, but you need large, ugly and expensive shifters and may or may not spend the rest of your days bleeding them - I guess this depends to a small extent on luck and a large extent to how well you set them up in the first place

Expensive and large are subjective, but I find it difficult to say, at a glance, whether a Shimano sifter is hydraulic or mechanical. If you have normal hands, it cannot be a problem. That leaves the matter of your wallet. That's your business.

3) Cable actuated hydraulics should overcome both these issues, but Hy:Rds seem to have attracted a large number of disgruntled posters who can't get them to work reliably. When working properly though they sound good - they have two pistons and auto adjust for pad wear. Juin Tech R1s are a closed system so they don't adjust for wear automatically, but they are cheaper and lighter then the Hy:Rds and seem to generally get better reviews.

Would this seem to be a fair summary?

Another compromise. Just go the whole way and get on with it. The combination of cheaper and lighter worries me. What's the catch?

I'm leaning toward the Juin Techs because I can use any old lever, they are relatively cheap and seem easier to live with then pure cable ones, and apparently have better modulation, but any input from anyone else would be much appreciated.

If anyone were to give me advice on modulation, I'd ask them to first define it. You'll then discover that the advice was just a phrase read in a magazine somewhere.
Nothing with a cable in can modulate better than a pure hydraulic line.

My other 'I've never used discs' before questions are:

1) How long do the pads last?
2) How long do the discs last?
3) How easy is it to change a wheel? I presume that if you have two wheelsets, the discs in theory should just line up (might have to adjust the pads a little for different amounts of wear, but this seems easy on the Juin Techs) but how does this work in practice?
4) Fade - I am about 75-80kg, and ride in reasonably hilly places, sometimes with panniers. I presume fade is not something I need to worry about unless I ride somewhere very hilly with very heavy panniers? Or can it occur in relatively 'mild' conditions?

Obviously the answers to all of these could be 'it depends' but entertain me

It depends.
Resin pads don't last as long as metal pads. Neither pad lasts as long as a good rubber pad.
The discs last forever.
Easy
Fade - another thing I'd ask for a definition, but just for kicks, since fade is just not an issue unless you tick all the "dont" boxes.

 

[KneesUp]

Another compromise. Just go the whole way and get on with it. The combination of cheaper and lighter worries me. What's the catch? .

As far as I can tell the Hy:Rds are 'open' which means they adjust for pad wear automatically, but as a result they have a reservoir of hydraulic fluid. The Juin Techs are closed, so they don't adjust automatically for wear, but as a result don't need the reservoir, hence they weigh less.

 

[PlanB]

I have a CaadX with cable disc brakes that are average at best.
I too looked at converting them to semi or fully haudraulic setups, but in the end just bought another bike with Shimano disc brakes.
The Shimano RS685 brakes are just fantastic, even if the hoods are a bit big and loose fitting.
I took my old road bike out last night, and having to go on to the drops to grab a handful of wooden brakes just felt weird.
But those Dura-Ace shifters sure did feel nice again .... infact I sat on the sofa watching the Vuelta last night whilst fondling them!

 

[Pale Rider]

I doubt you will have any fade problems from your proposed use.

Leaving the calliper aside, a good way to increase performance is a larger rotor, particularly at the front.

A quick google suggest the Juin Tech brakes are supplied with 160mm rotors, which is the smallest size.

A 180mm or 203mm at the front would significantly improve performance.

 

[KneesUp]

A quick google suggest the Juin Tech brakes are supplied with 160mm rotors, which is the smallest size.

A 180mm or 203mm at the front would significantly improve performance.

And I guess if I ever want to do that, there is an adaptor that simply moves the calliper to fit the larger disc? Or is it more complicated than that?

 

[Cycleops]

My Tektro cable cheapies are as sharp as hell, especially at the front with 180 rotors. The 160 rears were rather soft but changing the pads fixed them.

 

[PlanB]

a good way to increase performance is a larger rotor

Which is exactly what I did on the CaadX to improve the Cannondale cable brakes!

 

[Yellow Saddle]

And I guess if I ever want to do that, there is an adaptor that simply moves the calliper to fit the larger disc? Or is it more complicated than that?

Yes, there are adapters for different disc sizes.

However, bigger isn't always better. The best rule to decide whether or not your disc are too small is to look and see if they overheat. One buys larger discs not for better stopping force but for better heat dissipation. A large or small disc can produce enough force to make you go over the handlebars and you won't even know you to squeeze slightly harder on the small-disc bike to kill yourself, that's how little difference there is in required lever force.

Brake pads come in two types, resin (sometimes called organic) and metal (called all sorts of things from syntered to ceramic to god-alone-knows). These perform different functions. A resin pad is for operating at low temperature. I'm not talking ambient temperature but heat generated from stopping. Resin pads brake predictably, smoothly and silently within their lowish operating temperature. If you exceed that, they will squeal, smoke, fade and deposit gunk onto your discs.
Metal pads need much higher temperatures to operate at and are not suitable for low-performance jobs. Their co-efficient of friction increases once they reach operating temperature and from there on they can get hotter and hotter without fading. Use them at low temps (low performance everyday riding) and they are grabby, noisy and slightly unpredictable as they go into their hot and cold bands.

You regulate the temperature you want by changing disc size. It's no use having a huge 205mm disc with metal pads if you can't get it hot enough to perform and likewise, no use if your resin pads heat up the small disc too much.

Horses for courses.

 

[Banjo]

Which is exactly what I did on the CaadX to improve the Cannondale cable brakes!

Is there a bracket you can buy to move the brake unit up the fork to accomodate a bigger diameter rotor?

 

[Pale Rider]

And I guess if I ever want to do that, there is an adaptor that simply moves the calliper to fit the larger disc? Or is it more complicated than that?

Is there a bracket you can buy to move the brake unit up the fork to accomodate a bigger diameter rotor?

Spacers are available to mount the calliper further away from the rotor, although I've seen it done with a column of washers.

You may also need longer mounting bolts.

 

[PlanB]

Is there a bracket you can buy to move the brake unit up the fork to accomodate a bigger diameter rotor?

Yes there is, but I had a couple of 10mm spacers and longer bolts knocking around.
There is a noted improvement, but I think better pads helped also.

 

[Yellow Saddle]

Yes there is, but I had a couple of 10mm spacers and longer bolts knocking around.
There is a noted improvement, but I think better pads helped also.

How did you notice that improvement?

 

[paraffinlamps]

I had a Boardman CX Team that came with BB5 mechanical brakes . These are my thoughts and experiences using the bike as a winter bike .
The BB5 s did seem to need a lot of adjustment as the pads wore and seemed to rub or catch no matter how well you adjusted or fitted them . ( I followed the advice of loosening the bolts pulling the brake on to centre it and then tightening the bolts ) . After adjustment they would be ok for a few miles and then start to rub again . It was noticeably worse in wet weather when small bits of grit would caught , I suspect because the pads had to be so close to the disc .
I decided to try the Juin Techs as they were reasonably cheap and seemed the answer to all my problems . In fairness the front one wasnt as bad as the BB5 for adjustment but would still rub now and then and you would have to adjust after most wet rides due to minor pad wear .
The rear one was okish but seemed to take a lot of lever movement to come on ( I had compressionless cables as advised ) . It did however seem to keep sticking and not return properly . I put up with it for a while but one winters night , when it was about -5 , the rear brake locked on after I had braked to turn right . Further investigation revealed that it was not the brake but the cable that was not returning smoothly if at all .
The problem with a lot of disc bikes IMHO is the rear brake cable runs down under the bike and then along the chain stay and up towards the brake . This allows water/crap coming off the wheel to seep inside the inner and outer cables ( most likely by capillary action ) and cause sticking which in turn stops the brake returning to its rest position .
In the end I bit the bullet and went for the Shimano RS685 Hydraulic shifters and brakes . ( I paid around £380 from PX about a year ago ) They were fairly easy to fit and trimming the hydraulic lines was easy enough . Bleeding took a while and it seemed to take forever to get all the air out , but I persevered and to be honest the lever travel is no where near as far as mechanical / mechanical hydro .
I cant honestly say that the braking is noticeably any better . I have 160 mm rotors front and rear and all types stopped me just fine . ( Im 97 Kg ) , The beauty of the hydraulic ones is there is not need to constantly adjust the pads , they are fit and forget . I would say that you perhaps dont have to squeeze the hydraulic levers as hard to brake . ( for example braking from the hoods seems easier with hydraulic ) however there is not a huge amount in it and as I said all brakes stopped my just fine .
As for hood size , yes they are larger but I have large hands and havent really noticed the extra bulk . I have the other extreme of Di 2 levers on another bike and I can adapt to either without really noticing it .
Yes when there is heavy rain and grit in the country lanes upi occasionally hear scraping of the disc and pad .
If I had my time again with what I know now I would have gone straight from the BB5 to Hydraulic and saved a few bob . Yes they are expensive , but they just work .