Jipe

For me, cable actuated hydraulic disc brakes combine the drawback of the full hydraulic and full cable actuated disc brakes:
- For the weight, they are at least at the same level as average full hydraulic, there are ultra light hydraulic that weight less and have the same weight as cable actuated like the TRP.
- For the braking performances, they suffer from the same sensitivity to the quality and routing of the cables+housing.
- For the service, they have the same needs than full hydraulic.
- For the price, they are more expensive that average full hydraulic and than high end full cable actuated.

The fully cable actuated disc brakes cannot compete in terms of braking performances and progressiveness with full hydraulic, even with low end ones and are more expensive. Their only advantage is a lower weight than full hydraulic at he same or lower price level (ultralight full hydraulic are very expensive).

For the maintenance and reliability, my experience with full hydraulics from Shimano and Magura (both with mineral oil, I hate DOT) is very positive: very reliable, very low maintenance required. But I had a lot of problems with Avid and SRAM (which are very similar, Avid belongs to SRAM, both brands use DOT oil).

All this explain that most bike with disc brakes are equipped with full hydraulic and that there is a huge amount of types of full hydraulic and a small number of full cable actuated and cable actuated hydraulic.

Duragrouch

Well, not a surprise, from what I know of automotive pads. Metal pads, used on trucks and high-performance vehicles, were notorious for noise, in addition to wear of drums/discs, but conduct heat great, sometimes desired, sometimes not. Ceramic pads are the opposite, don't conduct heat, nice and quiet. There's been a lot of development in new materials in recent decades, but I haven't kept up with it. GM truck rotors started coming with gas-nitrided surface from the factory starting a few years back, that sounds great for both rotor durability and some corrosion resistance. I read that bike rotors are unique in using stainless steel, which conducts heat horrible, but preferred due to the (thin) thickness of bike rotors. I'll have to study this stuff before buying a disc system.

Ron Damon

There are bike rotors with Al-alloy sandwiched between the steel and with Al-alloy spiders, both for improved heat dissipation. The downside? The potential for warping.

Jipe

Indeed, most bike discs are made of stainless steel.

And they do the job pretty well because a bike with a cyclist on it weight much less than a car or a motorcycle (excepted on very heavy bikes like tandem and cargo bikes were due to the high weight there is a lot of heat to dissipate but heat dissipation is not the only problem, pads area and thickness is another, they are too small and too thin, and pads wear very fast)..

Shimano has Ice Tech discs with aluminum in the center between two layers of stainless steel.

I have those discs on some of my bikes and I didn't notice a real difference in heat dissipation but well in noise: when these discs become very hot they deform and rub against the pads until they cool down. The biggest the disc diameter, the biggest the problem.

Hope has ventilated discs, i.e. like on car discs, two layers with a gap in-between and fins that force air cooling.

Duragrouch

I just read that when researching whether bike discs were carbon or stainless steel. Shimano apparently does sandwich. Yes, warping potential, tell me about it; Aluminum has 3X the coefficient of thermal expansion than steel, something's gotta give! All the time I see triply cookware, nice stuff, in goodwill, warped, generally convex if overheated (sag, delaminate), or concave (wobbles on burner) if heated up or cooled too quick. Not as bad if thicker aluminum core, and heated up slow, but they keep making this stuff thinner. Original Al-Clad was thick. I used to have access to a hydraulic press and got good at flattening these back out with different diameter blocks. Now, I gotta pass on the warped ones.

If the cost comes down, I could see bikes going with carbon/carbon brakes like on a Porsche GT3 or C8 Z06, if the friction is not too much; No corrosion, lightweight, no fade, and I don't think they warp.

Ron Damon

Metal pads on bicycle disc brakes are also prone to noise.


Shimano Deore M6100 caliper & SLX RT66 180mm resin/metal-compatible rotor

When is heat conduction undesirable?

Duragrouch

Noise: Yeah I guessed, especially since bike discs are so thin.

Heat conduction: Good for discs, bad if conducts through the pad to the caliper piston, which has rubber/viton seals, and can boil the fluid if not great fluid and if it has absorbed water. I thought Corvettes decades ago (C4) went to DOT5 (silicone-based) brake fluid, because it didn't absorb water, stable over wide temp range, and high boiling point, but wiki indicates DOT5 is incompatible with ABS because it can foam under ABS activation, and ABS came only two years into the C4 generation, so that may be wrong. They now have DOT5.1 which is supposed to do all and leap tall buildings in a single bound.

I think my memory is wrong, I think C4s used DOT4.

Ron Damon

Shimano hydraulics use hydrophobic mineral oil rather than nasty DOT fluid so water absorption is less of an issue.

Duragrouch

Citroen developed a special hydraulic mineral oil (LHM green), hydrophobic (unlike earlier LHS "red" fluid they used which absorbed water), for their hydropneumatic suspension, and I think this was also adopted by Mercedes-Benz for their 6.9 (see movie Ronin), and I think the same stuff is used on Audi brakes, as well as others. Expensive! I'd bet that Shimano uses the same stuff, rather than reinvent the wheel.

Ron Damon

Under $13 for half a liter from an official Shimano store in my parish.

Duragrouch

(above) Nope, not same as LHM. In the early 1990s, LHM green was over $20 for I think 1 liter, which was over 4X the cost of standard brake fluid for cars. Looking now, LHM is $37/liter, unless you buy Bentley branded stuff (Rolls and Bentley both use LHM green) which is $115/500ml(!). So yes, the Shimano stuff looks like a bargain. I would say, weird, inventing their own, but not now, seeing current price of LHM green. But I'll bet it's darned similar in spec.

Jipe

Not only Shimano uses mineral oil in their bike disc brakes, Magura also use mineral oil.

SRAM and Hope use DOT.

But anyway, this comparison between car disc brakes and bike disc brakes is nonsense because there are about two orders of magnitude between the amount of energy to dissipate by bike brakes and car brakes:
- A classic bike is rated for a max total weight of about 125kg (bike+cyclist+baggage) while the empty weight of a typical car (not a huge SUV) is between 1500kg and 2000kg to which the weight of the driver, passengers and baggage must be added, so at least 20 times higher that the weight of the bike.
- And a car rides much faster that a bike, at least two times in cities about 5 times on highways (in most EU countries).

ChiapasFixed

😂 you guys are absolute geeks

who has had a hydraulic disc brake failure on a bike?

Jipe

I had problems with both Avid Code and SRAM Guide disc brakes.

No leakage but the brake caliper blocked when the ambient temperature is very high: in such condition, the oil expand and part of the oil should go back to the internal small oil tank located in the brake lever but this doesn't work well with those brake with as consequence that the brake pads constantly rub on the disc and heat up what makes the oil heat up and expand even more and eventually block the brake.

SRAM eventually replaced a pair of Avid Code for this problem under warranty but the new one had the same problem.

As said, never had any problem with both Shimano and Magura.

ChiapasFixed

Triple butter - yum 🤤

mi FnHon Storm frame set just cleared Mexican customs! Looking forward to starting that build. Ordered a very similar wheelset to what you have there, Litepro 32 spoke 2x lacing. That’s the part that should take the longest to arrive.
I have a Ruction Howitzer BB and crankset lying around that I think I’ll throw in there just to save buying something new although eventually I’ll probably replace with a hollow one. But the 34t chainring will probably need to be replaced right away. Would 50t be too much? Would that even work with a Shimano Altus 9 speed cassette and rear derailleur?
I guess we shall see!

Ron Damon

That Altus RD of yours is long-cage SGS and is rated for 34T max cog. Are you certain that's what you want to use?

Once again, there is no Shimano RD capable of spanning a wide range cogset (> 36T) below Deore and 10-speed. The Shimano entry point to wide range cogset is the Deore RD-M6000-GS, 10-speed part.

34T in the front is much too low.

IMO, a 50T chainring in the front is gonna be too tall for touring and climbing unless you've got no less than 46T in the back.


47T x 11-46T, 10-speed, Shimano Deore RD-M6000-GS

ChiapasFixed

yes, I have the 11-34 cassette and the shifter as part of the Altus group. Those groups sell used for cheap around here because they came stock on mid level Mexican mountain bikes and all the kids are upgrading to Sram 1x12.
So… something like a 46t with the 11-34 could work yes?

Ron Damon

You need to figure out what gear range in gear inches you want/need and learn how to calculate this on your own based on part (wheel/tire, cog and chainring) size. On 20" wheels, you want a medium-cage GS or short-cage SS RD, not a long-cage SGS job which is gonna come perilously close to the ground. The Shimano website is a wealth of information on RD and component specs. Use it.

Seeing that you may be bringing quite a bit of stuff, I should think you want no higher than 22GI on the low end for climbing.

Ron Damon

And back to Maxxis Grifter, 53-406.







BB height: 29.5cm

ChiapasFixed

My proposed setup gives me a range of about 20 to 78 gear inches. I may go with a 48t though…

Ron Damon

What are your doing about disc brakes? You may wish to create a stand-alone, separate thread about your bike builds titled, eg, "Bonkers in Bangkok: my Asian tour extravaganza bike builds" or "From Chiapas to Chiang Mai: my bodacious bike builds "

ChiapasFixed

Well so far I’ve ordered these, but I’m running out of time to do too many upgrades with shipping to Chiapas being what it is. Not a bad idea to consolidate everything into one thread as right now I have mostly invaded other threads 😆

Ron Damon

Fyi, the rotor bolts are Torx head. Also, the brake levers are I-SPEC EV mount so you'll need a narrow-band shifter to play nice with the levers. I use and can recommend the Deore M4100, 10-speed part.


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Jipe

The same levers exists at a similar price in I-spec type to be mounted on the handlebar with/under the collar of the brake lever.

ChiapasFixed

Would you happen to know if this brake levers would work well with Alfine 11 trigger shifter?

https://bike.shimano.com/en-US/produ...0/SL-S700.html

can’t find anything about brake lever compatibility