Front and Rear 4 Piston Brakes

[Jay Kay]

My SD Mountain has a 2+4 piston brake set up, which I would describe as good, but not great. On steep roads, it takes me a while to come to a controlled (I.e. no skidding) stop, even at lower speeds. has anyone converted to a 4 piston brakes system front and rear, and did it noticeably improve controlled stopping power?

 

[Stefan Mikes]

My SD Mountain has a 2+4 piston brake set up, which I would describe as good, but not great. On steep roads, it takes me a while to come to a controlled (I.e. no skidding) stop, even at lower speeds. has anyone converted to a 4 piston brakes system front and rear, and did it noticeably improve controlled stopping power?

Are you telling me your front brake is 2-piston only?

 

[Jay Kay]

4 front and 2 rear from memory - my bike is at my LBS getting serviced.

 

[Stefan Mikes]

It makes sense. The bike dynamics allocates at least 70% of the stopping power at the front. If you upgrade the rear to 4-pistons, you won't gain much. Moreover, excessive rear braking leads to rear wheel skidding.

All e-bikes I rode in mountainous areas had four-piston brakes front/rear, and at least 180 mm rotors. After brake pad inspection, it turned out the front pads were heavily worn while the rear ones were almost as new.

Not sure if this information helps you.

 

[Jay Kay]

It does thanks. My high school physics tells me this also. I suspect changing pads will be more effective but I thought it wouldn’t hurt to ask as I know there are some old heads on this forum.

 

[Merle Nelson]

I'm not an old head but, I have heard there are choices possible when it comes to brake pads. Some longer lasting (metalic?) Some grippier but shorter lived.

 

[Stefan Mikes]

It's semi-metallic.

 

[fooferdoggie]

first you need to make sure everything is really clean the pads may be contaminated. so get out the alcohol and clean it all well. if that does not work get out the sandpaper and sand the discs lightly and the pads. changing pads may be needed. the pad makeup wont really effect the amount of braking you get.

 

[rich c]

The biggest improvement you can make is to increase the diameter of the rotor. If you can lock up the brakes now, more pistons will not help.

 

[TForan]

I put a four piston hydraulic on the front and left the rear stock. Plenty of stopping power without the hassle of the rear installation.

 

[RunForTheHills]

I agree with rich c . Going from 180mm rotors to 203mm rotors will increase your stopping power by about 12%.

 

[JVBulman]

I see a suggestions of upgrading your pads and rotor, but something many people don't consider is that getting better tires can do wonders for improving your braking.

As @Stefan Mikes mentioned - 4-piston in the rear is overkill in my experience, often locking the wheel into a skid more than anything. It's also worth noting that R&Ms come equipped with MT2s with a straight hose fitting in the rear, while all 4-piston Magura brakes require a banjo fitting, meaning that you have to replace the hose as well as the caliper and that gets really expensive really fast given the internal routing on these bikes.

 

[theemartymac]

The biggest improvement you can make is to increase the diameter of the rotor. If you can lock up the brakes now, more pistons will not help.

Except for potentially improved modulation (control - through less sustained effort), and heat management. Big 4-piston blocks can absorb a lot of heat and still provide a consistent brake force with less fade - if you are running into that.

 

[m@Robertson]

Don't R&M use Magura brakes? That 4+2 setup sounds like the MT Trail they sell and that no doubt R&M buys and plants on the bike. I've never considered it to be a smart option. @Jay Kay your experience personifies why.

My braking technique is to engage the rears first, as the primary caliper, then ease into the fronts, progressively tightening both down until desired velocity is reached, or full stop. Build this into muscle memory and super powerful brakes won't send you over the bars in a panic grab on the levers. This bias towards the rear also creates more even brake pad and rotor wear. So I typically load up on the rear rotor size. I put 203's front and rear.

My brakes are Magura MT5's with MT7 4-piece pads (MT5 and 7 systems have the same caliper, and the 4-pc pads provide more torque).

Before you upgrade your rear caliper, first look at the pads on the back. What are they? The electric 7.S's? The green ebike ones? Try the 7.P (performance) compound. It'll grab harder without the sturm und drang that the gold 7.R race pads will deliver. Not satisfied after this incremental improvement? Upsize the rotor next. Ignore the limit of 180mm if such a rule exists. 203mm in back will be fine. Only then if you aren't happy, spend the money on the 4-piston caliper (and maybe downgrade back to the green pads).

Lastly, the motor/crankarms doesn't make the bike go. The brakes do not make it stop. The tires do all these things. Look at those as well if you are at your traction limits.

 

[theemartymac]

...The brakes do not make it stop. The tires truck bumpers do all these things...

lol

 

[Jay Kay]

Thanks team. Braking fade could be part of my problem as my rides often include 800m elevation gain and then loss on my ride home, meaning I am spending a lot of time on the brakes. Some really good suggestions above which I will look into.

 

[fooferdoggie]

Thanks team. Braking fade could be part of my problem as my rides often include 800m elevation gain and then loss on my ride home, meaning I am spending a lot of time on the brakes. Some really good suggestions above which I will look into.

if thats it the rotors like the ice tec or such would help. out shimano 4 piston pads have fins too so between them and the ice tech rotors we don't have overheat issues anymore on our tandem.

 

[rich c]

Thanks team. Braking fade could be part of my problem as my rides often include 800m elevation gain and then loss on my ride home, meaning I am spending a lot of time on the brakes. Some really good suggestions above which I will look into.

LOL elevation gain is never a braking issue for me.

 

[fooferdoggie]

LOL elevation gain is never a braking issue for me.

cause your too slow

 

[JVBulman]

if thats it the rotors like the ice tec or such would help. out shimano 4 piston pads have fins too so between them and the ice tech rotors we don't have overheat issues anymore on our tandem.

Sadly, Shimano pads are a different shape and their rotors a different thickness than those used by Magura.