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Brembo have launched their GR Pro MTB brakes.
Apparently with all the adjustments they have you can make them feel like your favourite brakes......
At around £1k - yes, 1000 of your finest English Pounds - including rotors and bleed kit..... I think I'll stick with my favourite brakes as they're a fair bit cheaper lol
Also a decent review here:
Brembo have launched their GR Pro MTB brakes.
Apparently with all the adjustments they have you can make them feel like your favourite brakes......
At around £1k - yes, 1000 of your finest English Pounds - including rotors and bleed kit..... I think I'll stick with my favourite brakes as they're a fair bit cheaper lol
Also a decent review here:
Yeah, but they’re red so obviously faster at slowing down…….or something like that.
Saw that review and the brakes are interesting but price, another mineral oil, another bleed kit and being noisy all put me off. I guess I'm a little jaded and already have brakes that work well enough that I'm inclined to stick with what I have unless something utterly ground breaking comes out.
Yeah, but they’re red
bet the red doesn't match my Zebs though
If I was paying that much for brakes I think I'd prefer Trickstuff because at least they look expensive.
another mineral oil,
Brembo, of all manufacturers, you would have thought would have gone with DOT fluid.
For me, DOT is always going to be the best solution, both for practical reasons and performance. On the practical side you can go to any Halfords and pick it up. No wondering just how compatible various mineral oils are if you can't get the fairy tears oil that Shimano/Magura/Brembo make.
And on the practical side, if any moisture does get into the system it is absorbed into the rest of the DOT fluid. With mineral oil it separates and normally ends up pooling in the caliper which can lead to 'interesting' performance issues.
Still, if you're spending £1000 on brakes I'm sure you can also pay your mechanic to perform a weekly bleed...
You’d do well to spend £300 on rotors and a bleed kit, no?
They come with 2 extra sets of pads, too
They're not the only brake at that price point. My preference is the intend Trinity. Brembo have tried MTB brakes before and then didn't. No sure what spares availability would be like. They look like maguras from 1998 though.
Comparable price to Hel brakes as well.
not for me and my budget but let’s not pretend they’ll not sell alright
You’d do well to spend £300 on rotors and a bleed kit, no?
They come with 2 extra sets of pads, too
I mean, I certainly wouldn't be spending that sort of money on rotors, but I've no idea how much Brembo ones will be and people are gonna want the full set aren't they? Their website even says the "Caliper and disc are designed to work in perfect synergy..."
There are definitely other rotors out there that cost £80 each.
For that sort of money, I'd at least want them to look nice.
All my "good" vehicles have / had Brembo brakes. I wouldn't let them near a bicycle.
Also for the company that invented the monoblock calliper to be making a split MTB calliper seems a bit odd. Is it actually theirs?
Also a unique pad shape which could make replacements challenging when your on a trip
Brembo, of all manufacturers, you would have thought would have gone with DOT fluid.
For me, DOT is always going to be the best solution, both for practical reasons and performance. On the practical side you can go to any Halfords and pick it up. No wondering just how compatible various mineral oils are if you can't get the fairy tears oil that Shimano/Magura/Brembo make.
And on the practical side, if any moisture does get into the system it is absorbed into the rest of the DOT fluid. With mineral oil it separates and normally ends up pooling in the caliper which can lead to 'interesting' performance issues.
And all that would equally apply to what you refer to as "DOT" fluids.
1) Not all "DOT" is equal, even ignoring DOT5. 4 and 5.1 just give minimum specifications, there are also low viscosity versions for ABS systems.
2) Not all Glycol based brake fluids are DOT compliant. The best ones aren't.
3) Not all brake fluids that are compatible with glycol/DOT4/5.1 systems are even glycol based, methyl borate ester is used in motorsport, but again we're outside the realms of the DOT specifications and closing in on your belief that you can't get good brake fluid in Halfords, only that argument might as well apply to mineral oil or DOT/Glycol/Ester based formulations.
4) If water gets in, the "if" is doing some really heavy lifting there. If your seals are worn then fluid will pass both ways and you have problems whatever the fluid is. If your seals aren't worn, your glycol based fluid is still drawing moisture through them. No one is bleeding their mineral oil brakes weekly to get rid of free water.
Also for the company that invented the monoblock calliper to be making a split MTB calliper seems a bit odd. Is it actually theirs?
IIRC Shimano dropped the one-piece design when they found that two part calipers were substantially stiffer?
I'm guessing there's probably a difference there between a tiny little bike caliper and the big chunky things on cars.
All irrelevant to their point. Make a brake that uses DOT 5.1 (or 4) and the end user will be able to pick up some fresh fluid just about anywhere that'll work in their brakes.
IIRC Shimano dropped the one-piece design when they found that two part calipers were substantially stiffer?
Shimano's two part calipers are the weak link in their system. But when buying a cheap deore brake I'll take that trade off. At the price these sell for I'd expect once piece, otherwise it looks very much as if someone is trading on the Brembo name rather than offering a true Brembo product in the mountain bike market.
4) If water gets in, the "if" is doing some really heavy lifting there. If your seals are worn then fluid will pass both ways and you have problems whatever the fluid is. If your seals aren't worn, your glycol based fluid is still drawing moisture through them. No one is bleeding their mineral oil brakes weekly to get rid of free water.
Not really.
There is a common misconception that because a hydraulic system seals well with high pressure it must seal even better in low pressures. This is seldom the case.
Also, if a system is designed to primarily seal when the pressure is positive then it doesn't necessarily follow that it will seal when the pressure is negative. Handlebars go from side to side and suspension goes up and down which creates constant opportunities for the brake system to experience negative pressure.
And if moisture/air getting into the system is a freak occurrence, why do all brake manufacturers recommend regular bleeding?
And why did Shimano redesign their calipers so that the new fluid flushed the entire caliper rather than leave a pocket next to the piston untouched?
As to the rest of your points about DOT fluid, I don't understand what you are saying. As far as I know, I can go into any Halfords and pick up a bottle of DOT 4 or DOT 5.1 and put it in my Sram brakes. Unless you're telling me I can't?
All irrelevant to their point. Make a brake that uses DOT 5.1 (or 4) and the end user will be able to pick up some fresh fluid just about anywhere that'll work in their brakes.
By the same argument, baby oil works in Shimano brakes and is even more widely available?
The other point I missed was that the calipers on your car have 2 seals, one seals the fluid in, the other keeps water and dust out. It's a very different design to mountainbikes where we only have one seal to do both.
Shimano's two part calipers are the weak link in their system. But when buying a cheap deore brake I'll take that trade off. At the price these sell for I'd expect once piece, otherwise it looks very much as if someone is trading on the Brembo name rather than offering a true Brembo product in the mountain bike market.
That's an individual manufacturers fault, not the overall design idea. Those Chinese trickstuff/hope copies are one-piece designs and reputedly have flexy calipers. Which raises the question has anyone ever measured the deflection in the calipers they allegedly copied?
I don't disagree, these look like they should say Tektro or Clarks on them. But there's sound reasoning why a 2 part caliper would be better.
Presumably someone at Brembo sat down with a blank sheet of paper, and without the preconception that expensive brakes must look like Trickstuff/Hope/Chinese knock-offs and figured that this is what the best bike brakes are.
As to the rest of your points about DOT fluid, I don't understand what you are saying. As far as I know, I can go into any Halfords and pick up a bottle of DOT 4 or DOT 5.1 and put it in my Sram brakes. Unless you're telling me I can't?
You can, but your point was that you didn't think the mineral oil in the bottle next to it on the Halfords shelf would be optimal because not all mineral oil is created equal.
I just pointed out that not all DOT4/5.1 is created equal either if you're worried about the minute of performance between them.
And why did Shimano redesign their calipers so that the new fluid flushed the entire caliper rather than leave a pocket next to the piston untouched?
Most calipers have this problem to some degree, even if they have the bleed and hose ports separately connected to the cylinders they don't actually flush the old fluid out. It's why the first step of changing pads in a car is to put a clamp on the hose and push the pistons back with the bleed open to force out the old fluid behind the piston.
By the same argument, baby oil works in Shimano brakes and is even more widely available?
Which comes back to my original point that Shimano (and almost every other manufacturer) says to only use its own special mineral oil. If I sent my Shimano brakes off for warranty inspection and they found it full of baby oil (or possibly even Magura oil) do you think the warranty would be accepted?
As far as I know, no DOT fluid brake manufacturer has said you have to use our own brand DOT fluid in our brakes or you might die.
2 piece calipers have long steel bolts holding them together.
I'm no engineer but it's not hard to imagine that's a stiffer setup than a block of alloy with the guts milled out then sliced almost in half.
Especially at tiny MTB caliper sizes.
True, but then SRAM didn't fix my brakes under warranty, even though they're made of plastic that swells up in DOT4/5.1 fluids. So that hypothetical argument isn't particularly sound 🤣
There is a common misconception that because a hydraulic system seals well with high pressure it must seal even better in low pressures. This is seldom the case.
I didn't say it wasn't. But if you have fluid passing in either direction then your brakes are f***** regardless of fluid type.
And your point is that the seal is less perfect when the seals are relaxed, but under that scenario the hydrophobic mineral oil is repelling water out, the hydroscopic glycol is drawing it in. Like I said, car systems use a double seal for that reason, mountain bikes don't.
By the same argument, baby oil works in Shimano brakes and is even more widely available?
Which comes back to my original point that Shimano (and almost every other manufacturer) says to only use its own special mineral oil. If I sent my Shimano brakes off for warranty inspection and they found it full of baby oil (or possibly even Magura oil) do you think the warranty would be accepted?
As far as I know, no DOT fluid brake manufacturer has said you have to use our own brand DOT fluid in our brakes or you might die.
SRAMs support site says to use SRAM DOT 4 or 5 brake fluid and even gives the part number. It doesnt say you can use any DOT fluid
2 piece calipers have long steel bolts holding them together.
I'm no engineer but it's not hard to imagine that's a stiffer setup than a block of alloy with the guts milled out then sliced almost in half.
Especially at tiny MTB caliper sizes.
You're not an engineer.
Those steel bolts are about 3x stiffer than the aluminum they replace, which is a significant amount of the caliper in tiny MTB calipers.
Compared to the huge Monoblock calipers made for cars where the caliper is almost closed at the ends because it's so much bigger than the disk.
Why do they need to be any stiffer? I'll take fewer places to leak (in or out) any time.
I didn't say it wasn't. But if you have fluid passing in either direction then your brakes are f***** regardless of fluid type.
And your point is that the seal is less perfect when the seals are relaxed, but under that scenario the hydrophobic mineral oil is repelling water out, the hydroscopic glycol is drawing it in. Like I said, car systems use a double seal for that reason, mountain bikes don't.
But with DOT fluid, any moisture entering the system isn't really a problem. What you will see is the boiling point of the fluid gradually reducing from very high to still pretty high. This is because any moisture is distributed throughout the system.
Any moisture that is present in a mineral oil system tends to pool at the caliper. This means that instead of a gradual reduction in boiling point you suddenly find that the boiling point of your system is 100 degrees.
There's also the related issue of mineral oil brakes mysteriously failing in sub-zero conditions. Again, even tiny quantities of water can destroy a brake if ice crystals start to form at the pistons.
Everyone has different priorities, but if I have the choice I will pick DOT fluid brakes every time.
SRAMs support site says to use SRAM DOT 4 or 5 brake fluid and even gives the part number. It doesnt say you can use any DOT fluid
Does it say to ONLY use Sram fluid and if you use other manufacture's fluid your bike might explode?
And more to the point, will they be able to tell the difference between their own fluid and the stuff I picked up from Halfords if I send them in for warranty?
Why do they need to be any stiffer? I'll take fewer places to leak (in or out) any time.
A decent idea, but there's still plenty of other places for it to leak (and it's only Shimano that I've ever heard of having this problem, and seemingly only on certain calipers/generations as none of mine ever did it.
Any moisture that is present in a mineral oil system tends to pool at the caliper. This means that instead of a gradual reduction in boiling point you suddenly find that the boiling point of your system is 100 degrees.
So the hypothetical water, which is repelled by the oil, would boil if there's enough of it?
I'm not even convinced you'd ever get free water in the caliper, whenever I've stripped them it's usually a gunky black emulsion whether it's mineral oil or glycol, I've never encountered free water in there.
Are you not getting this idea from criticisms of DOT5 fluid which behaves very differently and does legitimately form bubbles of water in the lines and calipers if you're not careful?
And even SRAM recommend their mineral oil brakes for people who don't want to bleed them as often.
Yeah, but they’re red
bet the red doesn't match my Zebs though
Even if it did to begin with Brembo red often ends up pink eventually. 😂
So the hypothetical water, which is repelled by the oil, would boil if there's enough of it?
Yes.
It takes a lot to get brakes up to 100 degrees but it can happen. See Kelly McGarry's crash in the 2015 Red Bull Sky Gate race for an example.
I don't even think there has to be much water. Water expands 1600 times its original volume when it boils (although obviously a pressurised environment would change that). Even trace amounts could cause brake failure if it boils.
2 piece calipers have long steel bolts holding them together.
I'm no engineer but it's not hard to imagine that's a stiffer setup than a block of alloy with the guts milled out then sliced almost in half.
Especially at tiny MTB caliper sizes.
You're not an engineer.
Those steel bolts are about 3x stiffer than the aluminum they replace, which is a significant amount of the caliper in tiny MTB calipers.
Compared to the huge Monoblock calipers made for cars where the caliper is almost closed at the ends because it's so much bigger than the disk.
Isn't that exactly what I said?
I said the bolts create a stiffer setup.
Isn't that exactly what I said?
I said the bolts create a stiffer setup.
Ahh sorry, my brain skipped over the word almost and read that as
"but it's not hard to imagine that's [a monoblock] a stiffer setup than a block of alloy with the guts milled out then sliced almost in half. [and bolted back together again]"
I don't even think there has to be much water.
Yes, but there still has to be some, which there generally isn't because the big advantage of mineral oil is that unlike glycol it doesn't transport the water past the seals in the first place.
Yes, but there still has to be some, which there generally isn't because the big advantage of mineral oil is that unlike glycol it doesn't transport the water past the seals in the first place.
As anyone who has run Shimano brakes in freezing conditions will probably be able to tell you, even if there shouldn't be any water in there it is still somehow in there.
And, like I said at the very beginning, just because a hydraulic system is very good at sealing at high positive pressures, it doesn't mean that it is very good at sealing in low positive pressures or low negative pressures. And low pressures caused by the movement of the handlebars and suspension, is exactly the state brakes spend most of their time in.
The idea that water can't find its way into a mineral oil braking system is wrong, imo. Even with all seals apparently in good condition.
Started out as a thread about some new brakes Bruni has been running for the past year but slipped into pedants corner. How did that happen?
Because the internet is full of experts who know better than one of the world's largest Motorsport brake manufacturers.
Started out as a thread about some new brakes Bruni has been running for the past year but slipped into pedants corner. How did that happen?
We've been discussing the engineering decisions that Brembo made when they were designing these brakes.
Apart from the colour, what would you like us to be saying about them?
Because the internet is full of experts who know better than one of the world's largest Motorsport brake manufacturers.
It's not so much that I'm saying I know more about designing brakes than Brembo (although I perhaps have more experience with pressurised hydraulic systems than many folk) but rather, whatever specifications Brembo prioritised were perhaps not the ones I would have focused on.
For an out and out racing brake, going with your own brake fluid makes sense. You can optimise the design around a very tightly specced fluid rather than support off the shelf commonly available alternatives.
A race bike is going to be maintained in optimal condition at all times and you don't have to worry about sourcing a particular fluid.
For the average consumer, I just don't see these advantages being worth the downsides. Like many other things I have opinions on, I'm more and more finding myself in the minority as time passes and manufacturer specified mineral fluid becomes the norm. C'est la vie.
By the way, who is derailing the discussion more. People who like to get into the minutia of engineering decision and their trade offs or the people whose sole contribution to the discussion is to slag off those of us who like to discuss things in detail?
Boy those brakes are red, aren't they!
Do Brembo use mineral oil in any other brake instead of DOT 4 style fluid? I suspect they're using mineral oil as it effectively now the standard for bike brakes with only Hope and Hayes? left using DOT.
I imagine those with bikes with motorsport livery inspired paint will be banging the door down to get some…
"I suspect they're using mineral oil as it effectively now the standard for bike brakes"
This is the reason Brembo gave.
