Issue 144 Kit Essentials - 4-Pot Brakes

Curas deserve a shout out for value for money also, RRP there is £175 but they are available for a lot less.

hope tech E4s for me all day long, just feel great, plenty of bite and modulation.
that said i've liked the sheer power of sxl/xt, never liked sram guides, trp spyre.
and got some magura SL, power is ridiculous, but along way off the feel of hope for me.

along way off the feel of hope for me.

Funny how brake feel is so subjective.

In an ideal world I'd like brakes with almost zero travel. Just the force applied to the lever multiplied to generate the braking force. There's still the ability to modulate (that's more a question of whether the pad+rotors coefficient of friction follows an ideal relationship with regard to speed/force/heat/time), but completely different to some peoples brakes where they prefer lever travel to be proportional to the braking force.

That said I'll ride anything. I don't dislike the feel of SRAM Guides enough to want to spend hundreds replacing perfectly good brakes.

I've got Curas and they've been fantastic, I can't fault them.

@honourablegeorge any tips on where to look for lower Cura prices? They don't seem to be stocked in as many places as the usual suspects.

Interesting what's happening at TRP. Thats 2 reviews saying you cant pull them in far enough on the reach adjust, and that the throw is really short. I've just taken off some Quadiems (well, to be accurate I've kept the calipers and made TRimanos) as they pulled a full centimetre more than my Deores before biting, and then had to be pulled a lot further again to get full power.

On the note of the Deores - amazing brakes for the money. Make SLX a bit pointless, at least with XT you get the nice dimples on the levers and cant pretend the reach point adjust does something

Anyone find it odd that not all brakes are mentioned in the verdict?

My new Orbea Rise has 2 pot Deores ,usual showroom sleight of hand, XT rear mech while downgrading more important stuff. Though on saying that and the bike shop guy planting the seeds of doubt in my head suggesting Hope or an XT 4 pot upgrade ( complete with wandering bite point 🙄)so far so stoppy perfect 👍
On the subject I was always a Hope brake fanboy until I bought a bike with Shimano brakes , then it was hello one finger braking ! 😎
Finally genuine Shimano pads under a tenner genuine SRAM double that so it's Shimano for me plus if I find the 2 pots lacking as the pads wear down I know for £100 I can swap the calipers to 4 pots .

Not had to bleed my SLX since 800 miles and 4 sets of pads. When they get low you do have to wind out the reach and give them a pump up I find. Then re set reach. Front is almost back plate to disc (running metallic pads). That’s with discs and pads both approaching minimum.

Only other maintenance is to check pads and pistons stay balanced and centralised as they wear. Again not had to do that on 3 sets of rears. Compared to my Tech 3s. They seem pretty fit and forget to me.

I like my tech 3 but do seem to need a bit more care.

Fitted Cura 4's last month after years of Hope T3 E4. I'm very happy with them.

Happy with my Dominions here, not entirely consistent to how the STW team found them it seems. I've commented on that specific review.

Could we stop defining brakes by the number of pistons? It's just daft. You can have lightweight xc 4 pots, you can have mighty dh 2 pots, I know it's the current hype to add pistons to everything but it's just not a defining characteristic. Always annoying when pushbikes insist on repeating mistakes motorbikes made decades ago. Must! Upgrade! To! 6! Pots! That perform worse in every way than the 4 pots I already have! But! 2! More!

Especially since half the industry struggles to produce a reliable brake anyway. But instead of having seals that don't leak, or brakes that can be bled without a phd, let's add more adjusters or more pots or magic rotors or propellors or 2 more of something, more things to go wrong and cost more. it's one thing if all the problems with brakes have been solved, but they haven't. Or rather, they have but it's unequally distributed, my 12 year old brakes are light for xc, powerful enough for dh, and reliable enough to be still going 12 years on but we've gone backwards more than forwards.

TBF I don’t think anyone has added more adjusters than when Juicy 7s came out in 2001*

*total guess

Recently installed the Tech 4 E4’s and found them to be a massive improvement over the Tech 3’s! I still have the tech 3’s just moved them across the other other bike. Nearly went with the Curas but didn’t want different pads and bleed kits etc

@P20

<< Anyone find it odd that not all brakes are mentioned in the verdict?>>

Yep thought the same.

keppoch

@honourablegeorge any tips on where to look for lower Cura prices? They don’t seem to be stocked in as many places as the usual suspects

146 Euro here, in stock... r2-bike had them at 129 not long ago.

https://www.bike-discount.de/en/formula-cura-4-disc-brake

I find the cheap brake pad comment funny. As if somehow paying 10x the price for pads actually means they’re really different. I’ve run Ali Express semi metallic pads on Shimano, Magura and Formula brakes and never noticed a difference between them and oem.

It’s packaging and branding that you pay the extra for. Same with bike wash, brake oil, fork oil etc. Motorbike fork oil is cheaper and works the same for example.

Just bought SLX as I managed to snap off the pad retainer housing on one side and they’re about 4 years old and were looking pretty worn!

Re: pads
After a pandemic-induced purchase of Trickstuff pads for my M8120 XTs, I'll say there's a difference (which makes me wonder how much of the Trickstuff magic could be down to pad compound). So much so that I ordered up another set to have on hand. And at the risk of tempting fate, I'm not experiencing Shimano's trademark wandering bite point with Trickstuff 2mm rotors.

YMMV

<< Anyone find it odd that not all brakes are mentioned in the verdict?>>

Yep thought the same.

Yeah theres surely a paragraph missing?

I agree about a firmer lever feel on the Tech4s being nice, BUT for me the much lighter action has meant much less hand fatigue & I wouldnt want to lose that, I really love these brakes

Worth mentioning that deore 6120 4 pots are £160 a pair at merlin at the moment? I’ve just ordered some.
https://www.merlincycles.com/shimano-deore-m6100-m6120-front-rear-disc-brake-set-213641.html

Could we stop defining brakes by the number of pistons? It’s just daft. You can have lightweight xc 4 pots, you can have mighty dh 2 pots, I know it’s the current hype to add pistons to everything but it’s just not a defining characteristic. Always annoying when pushbikes insist on repeating mistakes motorbikes made decades ago.

Agreed. I've moaned about this before. I've also seen 2 pots called "single piston" in the same paragraph as "4 pot" which seems like deliberate marketing speak to make them seem twice as bad again. Unless they were meaning brakes where only one side moves. I remember Avid BB5 cable brakes doing this, unaware of any hydro brakes that act in this way.
Pistons need to be circular, pad area is useful (but not the sole determiner of power). And yet the width of the braking surface on a rotor remains constant.

I suggest the way to go is 2 pot, larger pistons, larger square pads; and disks with a wider brake track to match.
Its the sort of thing Hope would do to raptuous applause, but if Sram did it, the internet would crucify them.

After a pandemic-induced purchase of Trickstuff pads for my M8120 XTs, I’ll say there’s a difference

I think there's probably 2 difference in most cases. And at least one other reason why.

1) All new pads feel better than a set a few months old, covered in all sorts of crap, overheated, glazed, etc etc.

2) Most people swapping pad brands looking for something better are probably swapping types as well. Of course Galfer, Trikstuff or Hope Organics will feel subjectively better to you if you hated sintered eBay specials. If you hate the feel of organic pads on the other hand....

Other point) eBay, Ali-Express, Amazon all get lumped together in these discussions as if they're one shop/brand. Just because you had a crap set of DodgyDave6969 brake pads off eBay, doesn't mean that all pads on all platforms are worse than the OEM's.

I suggest the way to go is 2 pot, larger pistons, larger square pads

Larger piston will travel less distance for the same lever travel. Which will either mean tighter running clearances or greater lever throw.

You can tweak the variables but in a system like this there is not much you can do to signifcantly change the clamping force of the calipers.

Larger piston will travel less distance for the same lever travel. Which will either mean tighter running clearances or greater lever throw.

when compared to a current style 2 piston, yes. But compared to a 4 piston - this is purely a funcion of total piston area isn't it?

Worth mentioning that deore 6120 4 pots are £160 a pair at merlin at the moment? I’ve just ordered some.

CRC are doing them for just under £60 and end at the moment too, so long as you don't mind swapping hoses over to get away from the euro/us configuration.

EDIT: linkey

https://www.chainreactioncycles.com/shimano-deore-m6120-oe-disc-brake/rp-prod213215

Ah yes saw those on CRC. I CBA with the faff but a bargain for those that can😂

when compared to a current style 2 piston, yes. But compared to a 4 piston – this is purely a funcion of total piston area isn’t it?

It depends on the total wetted area of the pistons/pistons and therefore the volume of fluid required to take up the running clearance, As this gets bigger the volume required to take up the running clearance increases, the lever has to travel further, or the running clearance needs to be made smaller

It depends on the total wetted area of the pistons/pistons and therefore the volume of fluid required to take up the running clearance, As this gets bigger the volume required to take up the running clearance increases, the lever has to travel further, or the running clearance needs to be made smaller

So am I understanding this right? -
using Hope as an example:
cross country brake - X2 has 2 22mm pistons - area = 242(pi)
Enduro brake - E4 has 4 14mm pistons - area = 196(pi)
Downhill brake - V4 has 2 14mm and 2 16mm pistons - area = 226(pi)

All are compatible with the same levers - in theory pushing the same volume of fluid for a given lever pull.

So am I understanding this right? –
using Hope as an example:
cross country brake – X2 has 2 22mm pistons – area = 242(pi)
Enduro brake – E4 has 4 14mm pistons – area = 196(pi)
Downhill brake – V4 has 2 14mm and 2 16mm pistons – area = 226(pi)

All are compatible with the same levers – in theory pushing the same volume of fluid for a given lever pull.

The amount of fluid pushed is the area of the pistons x the distance from the rotor. The seals enable a degree of compensation they can allow the pads to run closer to the disk. If you continued to increase the piston size you will reach a point where the lever cannot move enough fluid, or the pads would be so close that the brakes you rub like crazy. If you upsize the lever piston to move enough fluid you lose the force multiplication effect.

reeksy
Full Member

I find the cheap brake pad comment funny. As if somehow paying 10x the price for pads actually means they’re really different. I’ve run Ali Express semi metallic pads on Shimano, Magura and Formula brakes and never noticed a difference between them and oem.

Yeah, I got some super cheap aliexpress pads basically for a laugh, but they're now my favourite pads, not just because they're cheap but because they're excellent. Tested in the alps, at Fort William, the Mega... And on my obsolete 2 pot brakes 😉 I'd bet money that the same pads are for sale with different brands on for 5 times as much somewhere.

ayjaydoubleyou
Free Member

Pistons need to be circular

Nah. Formula's R0 had oval pistons. There's obvious downsides to it- they can't rotate at all in the bores so thta has servicing implications.

And at the risk of tempting fate, I’m not experiencing Shimano’s trademark wandering bite point with Trickstuff 2mm rotors

I think wandering bite point is down pistons not completely retreating back into the caliper between pulls, so thicker rotors should in theory reduce this.

When I have had wandering bite point, cleaning and lubing the pistons sorts it.

XT 4 Pot user with 203mm shimano rotors and Disco brakes sintered pads - they have been incredibly confidence inspiring this week in the Tweed Valley dust and heat even with my brake dragging tendencies.

Northwind
Full Member
Could we stop defining brakes by the number of pistons? It’s just daft.

Yep.