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Is a front 4 pot caliper upgrade worth it?

Scratching The Upgrade Itch.

2357 Views 29 Replies 11 Participants Last post by  epittman
I'm thinking about an SLX M7120 4 pot caliper upgrade for the front. It's going to replace the same 2 pot version that's on there now.

Nothing wrong with the current set up, I just want to replace as I've never properly experienced 4 pot performance before.

I had a quick go of my Buddy's all round Zee brake set up and didn't notice any real difference which is making me think twice about whether it's worthwhile.

Am I going to appreciate and notice the 10-20% power upgrade when the trails get steep or at that point where I may need it?

I keep hearing there isn't a downside and modulation is slightly better too, is that another worthy plus point of going for a 4 pot caliper?

Any thoughts, opinions, feedback is appreciated. Thanks! 馃憤
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I switched my wife鈥檚 bike which had an aging XT 2 piston to the latest SLX 4 piston.
There was a noticeable power increase. She鈥檚 not that great at modulation so can鈥檛 talk about that aspect.
Just replacing an aging component with a new one is an advantage
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I tend to be a "don't fix it if it isn't broke" type of person so I'd probably just leave it if it was me. I am 77kg fully kitted, so my 2 pot XT brakes (2 bikes) and Avid BB-7 brakes (3 bikes) stop me fine with a 185 rotor up front and 160 rotor in back.
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I wouldn't. If you start noticing fade, go with a bigger rotor. In my experience 2 pots are sharper and grabbier (instant bite) while 4 pots are more powerful and have more modulation. This is coming from my testing with Shimano, Magura, and Formula.
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What size rotors and what kind of pads are you currently using? And do you know what condition those Zee brakes were in?
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I switched my wife鈥檚 bike which had an aging XT 2 piston to the latest SLX 4 piston.
There was a noticeable power increase. She鈥檚 not that great at modulation so can鈥檛 talk about that aspect.
Just replacing an aging component with a new one is an advantage
My original calipers both started having sticky piston issues after around the two year mark.

This front (and rear) calipers are now about a year old.

Yes agreed, not so bothered about the modulation side of performance either, it's that bit more power that's tempting me most.

Thanks for the reply @Mick-e .
I tend to be a "don't fix it if it isn't broke" type of person so I'd probably just leave it if it was me. I am 77kg fully kitted, so my 2 pot XT brakes (2 bikes) and Avid BB-7 brakes (3 bikes) stop me fine with a 185 rotor up front and 160 rotor in back.
I'm just over 100kg kitted up, I suppose that extra 25kg makes a difference.

Your right about changing for changing sake and I feel the same.

Looking around and seen a couple of good deals at the moment. I'm considering selling on the 2 pot caliper, if not keeping it for spare parts, either way it deffo wouldn't go to waste.

Lol, wow, lots of bikes @sgltrak! 馃This hardtail is my only bike at the moment, it's running well and happy with the rest of the upgrades on it.
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I wouldn't. If you start noticing fade, go with a bigger rotor. In my experience 2 pots are sharper and grabbier (instant bite) while 4 pots are more powerful and have more modulation. This is coming from my testing with Shimano, Magura, and Formula.
I do like the instant bite feel I get now. Did a really long steep descent a couple of weeks ago and had rear brake fade for the first time but realised it was in need of a bleed so maybe it wasn't brake fade after all?

I've always had Shimano brakes over the last few years. I did look at the Magura 4 pot caliper as really tempted to do the 'Shigura' thing, I've heard it's an unbeatable combo but those calipers are pretty expensive. 馃槵
What size rotors and what kind of pads are you currently using? And do you know what condition those Zee brakes were in?
Yes, good point @2021Mach6 and would have blamed a bad set up or worn pads etc. but Buddy's Zee's are all good. He's not into bike maintenance so I did a lever bleed on them and replaced the pads recently so I'd say they were 'normal' with nothing that would effect their true performance.

Reckon I didn't notice because I only had a quick hour blast around on tame local trails?

I'm running 203mm front and 180mm rear RT66's so pretty decent and nowhere else to go with improving on that side of things.

Trying out ceramic pads for the first time on the front and haven't bothered changing out the stock resin pads that came with the rear caliper. I do usually always go for non finned (cheap) sintered all round.
Brake pad replacement costs may rise, lol.

I am a fairly 'late' braker and rely on an immediate and predictable lever response, so good ole 2-pot XTs with metallic pads on a 180 rotor worked well for me. However I seem to have gained a wee bit of weight and a slightly smaller bit of my old downhill speed back, and found I needed brakes with moar powwwwwwweeerrrrr!

So I just* upgraded my rotor and swear I got at least that paltry +10% in braking power that switching to 4-pot gets you.
It's also a consumable that was fraction of the cost of new 4-pot brakes without the built-in added cost and potentially reduced reliability of 2x the pistons/seals and pads.
I'm running a Magura 203 MDR-P rotor now, so it's a Mag-mano setup.
Stopping power is noticeably improved, and I am getting zero fade over some fairly lengthy descents.
Plus it looks pretty bad-a$$, imo!
Wheel Tire Bicycle Crankset Bicycles--Equipment and supplies

*I also 'just' flushed my lines and installed fresh metallics with the fancy fins. But it was really all about the rotor!

Edit: Qualifying my 'nah don't bother' poll response to acknowledge that if you are on the biggest rotor your fork can take and are using metallic pads and still want more brake, then 4 pot may be the last best option.
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Brake pad replacement costs may rise, lol.

I am a fairly 'late' braker and rely on an immediate and predictable lever response, so good ole 2-pot XTs with metallic pads on a 180 rotor worked well for me. However I seem to have gained a wee bit of weight and a slightly smaller bit of my old downhill speed back, and found I needed brakes with moar powwwwwwweeerrrrr!

So I just* upgraded my rotor and swear I got at least that paltry +10% in braking power that switching to 4-pot gets you.
It's also a consumable that was fraction of the cost of new 4-pot brakes without the built-in added cost and potentially reduced reliability of 2x the pistons/seals and pads.
I'm running a Magura 203 MDR-P rotor now, so it's a Mag-mano setup.
Stopping power is noticeably improved, and I am getting zero fade over some fairly lengthy descents.
Plus it looks pretty bad-a$$, imo!
View attachment 1967667
*I also 'just' flushed my lines and installed fresh metallics with the fancy fins. But it was really all about the rotor!

Edit: Qualifying my 'nah don't bother' poll response to acknowledge that if you are on the biggest rotor your fork can take and are using metallic pads and still want more brake, then 4 pot may be the last best option.
馃槅 Yes it's a month after Christmas, it's winter so I've not been putting as many miles in so my 100kg is a conservative estimate. That time of year when pads wear down quicker and brakes feel less powerful. 馃槂

After all the usual Shimano brake issues it's going to add another set of pistons and seals to contend with at some point. Thinking just bad luck as those Zee's never seem to have problems and they've just kept on going, trouble free for at least four years now.

Yes that's a bling set up you got there @CyNil_Rider... looks nicce! 馃

Thanks for your comment and vote, you've given me an alternative to consider... or maybe a new 4 pot and bad#ss rotor too. 馃槻
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Nope... unless you have overheating or other issues.

I built up a 150mm FS 29er a few months ago and put XTR 9020 2-piston (with 180mm Ice Tech rotors and metallic pads) on both front and rear. 2-piston are lighter in general. These brakes, a set of older XTR 8020's plus SRAM ones I run on other bikes slow down my ~200 lb / 91 kg jolly carcass quite effectively. With a fluid replacement on occasion (couple years or longer) none of gotten sticky or wear pads unevenly.
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Nope... unless you have overheating or other issues.

I built up a 150mm FS 29er a few months ago and put XTR 9020 2-piston (with 180mm Ice Tech rotors and metallic pads) on both front and rear. 2-piston are lighter in general. These brakes, a set of older XTR 8020's plus SRAM ones I run on other bikes slow down my ~200 lb / 91 kg jolly carcass quite effectively. With a fluid replacement on occasion (couple years or longer) none of gotten sticky or wear pads unevenly.
Your right of course and this upgrade would be the first time I've contemplated replacing a fully working component without really having a good reason to.

I'm not bothered about weight, not much point saving a few grams here and there as I'm certainly no athlete. I tend to go for durability over all else.

Another option I've looked at is the equivalent XT caliper which I'd be happy with for the quality aspect but hard to see how the XT is better than the SLX in this instance.

Nothing against them and not much first hand experience but not a fan of Sram brakes in general.

Thanks and appreciate your honest, no nonsense input @edubfromktown. 馃憤馃挴
I wouldn't. If you start noticing fade, go with a bigger rotor. In my experience 2 pots are sharper and grabbier (instant bite) while 4 pots are more powerful and have more modulation. This is coming from my testing with Shimano, Magura, and Formula.
I tend to agree with this (2 pots sharper than 4). I've swapped XT 2 pots for XT 4 pots and experienced exactly that on two different bikes.

As for needing 4 pots over 2... depends on just that... need. I have 4 pots, but to be honest, I can easily go over the bars grabbing 2 pot XT's. So do I need 4 pots? Well heck yeah, 'cause they're cool! 馃榿
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Another good reason and plus point @fredcook! 4 pots are cool, maybe it's juvenile and no one else will even notice, but I'll know. 馃檪

I suppose losing the instant grab feel is a minus point or slight compromise which I'll get used in no time?

Going off votes, I should go for it, comments are mixed but on the whole, a positive move and worthwhile upgrade.

I read or heard somewhere that less grabby feel is by design, as in the smaller leading edge pistons moving just before the bigger pistons start taking effect or is that design element only to do with avoiding brake squeal? 馃

I've just put a bid in on a brand new SLX caliper, obviously if I win (for a below average price) it's happening, if I don't then maybe I'll wait until I need to change a caliper for a legitimate reason.
I don鈥檛 think you will notice a night and day difference. I think the biggest gain is heat management given double the pad area to absorb and dissipate heat. I often wonder about the physics: given same master piston and two different sizes of slave piston, force should be the same? How does more friction surface area play in if at all? I鈥檇 like to hear analysis on this.

to this point i have magura trail sports on my fat bike with 160 rotors. I run 203s on other bikes but don鈥檛 get going nearly as fast on my rigid fat bike plus mainly winter/ snow riding conditions. They have 4 pot front/ 2 pot rear and i never notice a difference. Although the recent magura interview on Down Time claimed 4 pot has more power and 2 pot has more modulation. Maybe i am not sensitive enough to notice.

final thought: i love my 8000/mt5 shigura setups (so much i run it on 2 bikes). But discovered the hard way, if you buy magura calipers only they don鈥檛 come with hoses and more importantly no banjo. That adds $100 to the pair so it鈥檚 probably more expensive to buy magura mt5 calipers and brake lines (to get the banjos) a la carte than it is to just buy the entire brake assembly.
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I don鈥檛 think you will notice a night and day difference. I think the biggest gain is heat management given double the pad area to absorb and dissipate heat. I often wonder about the physics: given same master piston and two different sizes of slave piston, force should be the same? How does more friction surface area play in if at all? I鈥檇 like to hear analysis on this.

to this point i have magura trail sports on my fat bike with 160 rotors. I run 203s on other bikes but don鈥檛 get going nearly as fast on my rigid fat bike plus mainly winter/ snow riding conditions. They have 4 pot front/ 2 pot rear and i never notice a difference. Although the recent magura interview on Down Time claimed 4 pot has more power and 2 pot has more modulation. Maybe i am not sensitive enough to notice.

final thought: i love my 8000/mt5 shigura setups (so much i run it on 2 bikes). But discovered the hard way, if you buy magura calipers only they don鈥檛 come with hoses and more importantly no banjo. That adds $100 to the pair so it鈥檚 probably more expensive to buy magura mt5 calipers and brake lines (to get the banjos) a la carte than it is to just buy the entire brake assembly.
Could be wrong but more piston surface area pushing on bigger pads with more friction material is the only reason for the small power gain and better heat dissipation?

I think your right that any difference won't be that noticable overall.

I don't think excess heat build up is much of an issue for me either.

The caliper I'm looking at doesn't come with pads so planning on my fitting normal sintered choice, no Icetech fins or rotors required.

Yes, same here, mildly irritating that these caliper only purchases don't come with a banjo bolt and is going to add cost. Don't know if my 2 pot banjo bolt is compatible with the 4 pot caliper.

I guess Shigura's are a possibility at some point in the future but not now considering the upgrade costs. 馃槵
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^^
I always thought it was because, compared to 2-pot calipers, it takes 4-pot calipers 2x the force (or is it 2x^2?) over 2x the surface area of 2x pistons/brake pads to get roughly the same clamping force on the rotor - but the levers are not equivalently leveraged/powerful enough e.g. you do not get 2x lever throw with 4-pot.

So a smaller surface (2-pot) area builds pressure more easily which provides grabbier stopping, and heats up faster as all the braking energy passes through a smaller surface. The converse would be true then of 4-potters, by relative comparison.

Just to muddy the water, but carry on a theme... A larger rotor, say 201 vs 180mm would have the effect of increasing the rotational speed of the disk, but decreasing the force needed to slow it. = more grabby and more heat generated, but you get greater heat dissipation from the greater mass and surface area of the larger rotor.

Final thoughts: Heat management is critical. 4-pot may generate less and dissipate heat better than 2 pot. Larger rotors may also generate less and dissipate heat better than a smaller one. Which then, caliper count or rotor size, is more significant in managing heat?
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馃槅 Lol, huh? Too complicated for me. Hopefully I'll watch this physics lesson unfold with interest but it's beyond my scope of understanding or desire to get my head around. 馃憤
Your right of course and this upgrade would be the first time I've contemplated replacing a fully working component without really having a good reason to.
That's some willpower right there. I wish I had you discipline! Couple unnecessary splurges, but mostly tires and brake pads.

The one thing I'm completely unreasonable with is grips though. Maybe it's OCD, I don't know, but anytime I get dirt underneath them, which is fairly often cause I crash a lot, I replace them. Just knowing there's even a chance there's dirt under my grips keeps me up at night. It's very bizarre behavior and there's no reasonable explanation.
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