Generally you don’t need power on the rear brake, it’ll just lock up, you need heat dissipation because the rear tends to get dragged down long descents. The front brake is the one you rely on when you really need to stop so I would stick with the conventional wisdom and put the 4-pots on the front and 2-pots on the back (I have two bikes set up that way). If you do find that you are overheating the rear, a larger rotor will probably help more than a 4-pot caliper.

Still, there’s no harm in trying it to see what it’s like. It’s your bike, set it up to suit what you do.

The calliper and pads are one great big heat sink.

The rotor is the main heat sink. Brakes generate enough heat the they would literally melt if you rode in a vacuum – they are cooled by air. To cool the pads, you need to allow air to flow between the pad and the rotor. This is why continually dragging the brake is so bad – the pads are continually in contact with the rotor and don’t have time to cool off. If you brake hard then ease off the brakes for a second or two, it gives the pads time to cool off and you’ll get less heat transferred into the caliper. Yes, I know that on some descents that’s not possible, especially if you are racing. In that case a larger rotor and 4-pot calipers make sense, but for most people, most of the time, a 2-pot on the rear with a 180 mm rotor should be perfectly fine.

Setting oneself up for the uncontrollable skid of death.

you can alternate front and rear as well to reduce the problems from dragging

I ran my Cotic with 4-pot front and 2-pot rear, both on 203 discs – works well.

I’ve now an eeb and that’s got 4-pots both ends with a 223 front and 203 rear – works well

In the early days of teeny tiny power meters, say (c. 10 years ago?) SRAM did a decent piece of research into mtb braking. It’s on the internet somewhere, although I don’t care to find it right now.

They stuck power meters on Fr and Rr discs to see whats going on.

Points for summary were that most riders, even the pros, use their rear brakes for speed moderation more than they realise and that the outcome for better control of this was to have modulation – They fell short of stating a 4 pot would be optimal, I guess because individual brake characteristics cloud the point, but they did say bigger discs for modulation, and if you’re chasing subtlety of control, a 4 pot on the back seems to make sense to me, irrespective of its other heatsinking benefits.

Read of that what you will. I happily rode 4 pot front, 2 pot rear, with a smaller disc on the rear for a number of years and actually increased disc size and went 4 pot due to ‘in extremis’ heat management concerns, but I do think there is an improvement in subtle control, which is useful if you’re they type of rider that can use it.

Whether that is the larger disc or the four pot I couldn’t tell you because I did them both at the same time.

It’ll be fine. You probably won’t notice any difference. Most people tend to drag their rear brake so it might even be beneficial.

 it seems to me 4 pot on the rear would make more sense.

No, the more powerful brake on the front makes more sense, that’s why everyone does it that way. If you need more power on the back, run 4 pots front and rear. If you’re a chronic brake dragger, run bit rotors and 4-pot calipers front and rear.

I ended up with a 2 front and 4 pot rear set after Chiggle sent me the wrong item.  I agreed to keep it after they sent me pack of bars/olives so I could swap them round.  Regret it now as I need spare pads for about 9 types of brake instead of 8, and when bikepacking long trips things like extra sets of pads adds up (especially when a single set fits into your puncture kit)  I don’t notice any difference with the 4 pot!

4 pot F & 2 pot R on my xc bike. I’ve set up my R so it bites first to scrub a bit of speed before the F bites. Then when the stronger F bites the bike is more controllable. Reason for me is I find R wheel skids easier to control then F one’s. I’m sure someone will be along soon to say that’s a stupid thing to do but it works for me….

So, in my head reading the comments, I need to bin my 180mm and matching 4-pot Deores.

Edit: I just read that Enduro article!

I need 200mm front on a 4-pot organic (less cooling, heat up quicker, but more ultimate power and initial bite) and 220mm rear on a 2 pot sintered (better cooling for about the same power, less fade when pads get hot, more controllable)?