Interesting Aliexpress finds! - good deals, interesting stuff, new products etc!

[Fat Larry]

Anyone tried these? https://www.aliexpress.com/item/1005010063774995.html?

Six pot mtb/ebike brakes.

[pushpush]

Anyone tried these? https://www.aliexpress.com/item/1005010063774995.html?

Six pot mtb/ebike brakes.

Pointless. Most people don't even need 4pot brakes. It is just more moving parts and seals to fail.

[JJx]

Pointless. Most people don't even need 4pot brakes. It is just more moving parts and seals to fail.

Agreed, generally, more pistons just add thermal capacity, braking force is more pad/rotor diameter dependent (Though variable leverage like servowave can also change this). I've ran 2 pot calipers on on DH bikes before, with semi metallic pads and enough rotor it isn't a problem.

I only run shimano brakes these days cause they are so reliable, and so easy to bleed. I have a set that I've had for over a decade, only needing 1 lever bleed.

In My opinion, best value for brakes:

Shimano mt200, I can typically get these for 40-50$ CAD, replace the stock pads, and these are very capable. The lever is a not ideal for 1 finger braking, but it can be adjusted inboard to work fine.

Shimano MT420, I can typically get these for 90-100$ CAD, I'll spring for these for bikes that will see more lift service, or if their for someone with small hands (the lever is a bit more comfortable)

[Tijoe]

Anyone tried these? https://www.aliexpress.com/item/1005010063774995.html?

Six pot mtb/ebike brakes.

Why stop at 6 pistons,   Instead go right to 8 pistons!   

https://lewistech.store/products/ep8-with-ep6-brake-set?srsltid=AfmBOoqDqK8_VSYpoxUVs8tKXDqDIeNwW-fTFLWX8gd256usgLRlMN_W

[jonathanf2]

How about go 8x2 for 16 piston stopping! 

https://www.aliexpress.us/item/3256809253308501.html

[Tijoe]

How about go 8x2 for 16 piston stopping! 

https://www.aliexpress.us/item/3256809253308501.html

Personally I would go with your proposed 8X2, 16 piston stopping, but I would pair it with a Hope Tech 3 E4 Duo Hydraulic Lever Set.

https://www.rei.com/product/221062/hope-tech-3-e4-duo-hydraulic-disc-brake-and-lever-set?sku=2210620002&store=&CAWELAID=120217890015923531&CAGPSPN=pla&CAAGID=101279516296&CATCI=pla-1049460956044&cm_mmc=PLA_Google%7C21700000001700551_2210620002%7C1049460956044%7Cbrand_flag%7C10012059830&gclsrc=aw.ds&gad_source=1&gad_campaignid=10012059830&gclid=CjwKCAjwr8LHBhBKEiwAy47uUnohSD0WL3yyW0NojRBN-G1TJ16Ol9igG8KF5UkCIo1_ATtWt0M1GRoCvJIQAvD_BwE

[amacal1]

Personally I would go with your proposed 8X2, 16 piston stopping, but I would pair it with a Hope Tech 3 E4 Duo Hydraulic Lever Set.

For those times when you need to stop a runaway city bus using only your road bike.

[jonathanf2]

I've been watching videos from MTB parks in China, these dual caliper adapters appear to be quite popular over there. Someone on here should try them out!

[Tijoe]

I've been watching videos from MTB parks in China, these dual caliper adapters appear to be quite popular over there. Someone on here should try them out!

In Japan, I think these types of brake set-ups are called "Sumo Brakes"   

[gribs]

Anyone tried these? https://www.aliexpress.com/item/1005010063774995.html?

Six pot mtb/ebike brakes.

Those look like an exact copy of the Hope Tech Evo lever from years ago paired with a close copy of the M6 calliper. I'll bet they take the same pads.

[Tijoe]

Back to a more serious perspective.  Does anyone know if these larger 6 and 8 piston calipers and brake lever hydraulics use the same standard ID hydraulic hoses as more common 2 and 4-piston brake hoses, or do they have a larger hose ID.   One would think that to get proportionally the same brake response, feel and modulation of these huge calipers, one would want a hose with a larger ID, especially for a rear long hose.   
You know, line pressure, flow rate, and fluid velocity  P =F/A : Q = V/T and V = 0.3208 X Q/A. 
What effect does the hydraulic fluid's viscosity and pressure drop / head loss have inside the line? 
(Perhaps why these larger brake are using DOT fluid instead of mineral oil? -  DOT fluid has lower viscosity than mineral oil?)

Perhaps it is a non-issue for little bicycle hydraulic brakes versus automotive vehicle brakes.

Edit:  I know that in larger calipers that the fluid volume inside the caliper required to move the pistons is larger, and that the lever hydraulics will match this volume.  The ID of the line will move this volume, either at higher pressure, and/or at a slower speed.  This can be compensated for by a master cylinder sizing ratio to caliper volume, or by the lever action.    Seems to me that the hose ID has an effect on how the brakes ultimately perform.

[gribs]

Hope use the same hose over all their brakes and the levers can be used with any of the callipers. That's been the case for a very long while. There's generally enough adjustment to set the feel as you'd like to a certain degree. My V4's (longer travel, soft, bite close to the bar) feel very different to a mates (Short travel, firm and away from the bar) and my E4's are somewhere between. As a long term Hope user (I started on C2's) I've never seen the need to use anything other than DOT fluid for brakes as from a performance point of view it does the job and the environmental concerns are insignificant compared to automotive use. Only the French use mineral oil for Automotive braking so it's clearly wrong.

[Tijoe]

Researching a little more, I find there are 3, ID hose diameters that are used on the majority of disc brakes.

2.0 mm: Some manufacturers use this size.
*2.1 mm: Commonly used for Shimano BH90 systems.  (17% more area than 2.0mm)
2.5 mm: Often used for Shimano BH59 systems and some older Tektro models.  (29% larger area than 2.0mm)

* 2.1mm ID is the most common ID hose.

A smaller ID creates higher fluid pressure for a firmer, more direct feel, while a larger ID requires more fluid volume per lever pull, resulting in a softer feel and potentially less responsive power if the system is not designed for it.

[Fat Larry]

Why stop at 6 pistons,   Instead go right to 8 pistons!   

https://lewistech.store/products/ep8-with-ep6-brake-set?srsltid=AfmBOoqDqK8_VSYpoxUVs8tKXDqDIeNwW-fTFLWX8gd256usgLRlMN_W

I've watched a bunch of brake reviews lately. Lewis are supposed to be as good as Trickstuff in terms of stopping power/reliability/no fade etc. Might get a set at some point.

Agreed, generally, more pistons just add thermal capacity, braking force is more pad/rotor diameter dependent (Though variable leverage like servowave can also change this). I've ran 2 pot calipers on on DH bikes before, with semi metallic pads and enough rotor it isn't a problem.

I only run shimano brakes these days cause they are so reliable, and so easy to bleed. I have a set that I've had for over a decade, only needing 1 lever bleed.

In My opinion, best value for brakes:

Shimano mt200, I can typically get these for 40-50$ CAD, replace the stock pads, and these are very capable. The lever is a not ideal for 1 finger braking, but it can be adjusted inboard to work fine.

Shimano MT420, I can typically get these for 90-100$ CAD, I'll spring for these for bikes that will see more lift service, or if their for someone with small hands (the lever is a bit more comfortable)

Ali has what i think are grey market shimano brakes for pretty good prices. MT420 sets around $130nzd and MT520 calipers are $115nzd to me. Haven't seen any mt520 sets but the levers are available for around $100nzd.

Where are you getting your prices?

How about go 8x2 for 16 piston stopping! 

https://www.aliexpress.us/item/3256809253308501.html

That is hilarious. I can see the adapter failing at the lower bolt though given it has all the force of a calliper going through it. 

Also wouldn't you need to double the size of the piston in the lever?

[Tijoe]

Also wouldn't you need to double the size of the piston in the lever?

Yes, or have the pistons travel 1/2 as far, or pull the lever 2X further down for the same pressure to be applied on the pads.

This is why I posted the Hope Tech dual levers, you could run 2 sets of calipers on the rear with that doubling bracket.  One could crunch the numbers or spend a lot of money experimenting to see if there is any way to achieve better stopping overall.  I suspect that your rear tire would become the limitation trying to grip that much braking power to the ground.   

OTOH,  I have often thought that having 2 independently operated calipers on the back could double the cooling effect on the calipers, where I literally discolored/cooked the rotor because it became too hot during very long steep high-speed descents.   (But this has happened perhaps 3 times over the past 5 years.) 
If I was a high speed downhiller I might want 220 rotors with dual calipers in back.
What I have found is that my DH fiends just go faster and use less brakes overall than I do.  Their age is much younger, they weigh less, when they crash they bounce and don't brake bones, therefore they just hang it out farther on the trails, using less brakes than I do, so why do they need more braking power?