Over the past few years, its seems like more and more regular cars have multi-piston brake calipers like the new subaru impreza. 10 or 15years ago, even performance oriented cars didn’t frequently have those until you went pretty far up market. And it doesn’t seem like it is for marketing, since it isn’t often advertised. If single piston calipers were good for an audi s4, why does a new subaru impreza need multi-piston calipers? have there been developments in cost or technology?
Like everything…as better technology becomes cheaper it becomes more common.
My car from 1969 has 4 wheel, 4-piston brakes and it always seems anachronistic as heck considering I had a rental Versa with rear drums a few years ago.
Most stuff was already written but this: Modern Cars brake an awful lot by themselve. Early Cruise Control let you go above your set speed if engine braking wasnt enough, now the Car constantly brakes whenever it reaches a Threshold. Lane assist brakes single discs to keep the Car where it should be, same for torque vectoring.
Most often the rear brakes are used for these systems, so pads in the back get replaced way more than the front, where the big braking power is happening.
Mutli piston calipers have better performance than a single piston caliper through more pad area and more even clamping force. Cars are faster and heavier than they were 10-15 years ago. Technology is better and costs are cheaper as well.
Brakes turn kinetic energy into heat, the rotor then dissipates that heat. Multiple pistons dont necessarily improve the braking performance. My thought on this was because of the weight and because aluminum is less energy intensive to cast (cheaper). A lot of dampers are also aluminum now, and so are uprights, so mass has for sure been a large factor in the decision making process for most car manufacturers.
I just discovered my '09 Lincoln Town Car has huge two piston calipers in front. It’s a 4300 pound barge. It needs the stopping power.
I can speak to experience that panther brakes are absolutely nothing to write home about. A 4000+lbs car with 12" rotors up front and I believe 11.8’s in the rear.
I went with 13" wilwoods all around, 6 piston up front 4 piston in the rear.
I think a lot of it is marketing and this point. Oh, the competitor has 4 pistons? We’ve got six
bladespistons!This is exactly it. Most people just think bigger brake = better, but 99% of people aren’t tracking their cars and it doesn’t make a lick of difference in any standard driving situation (just about the only time it does matter is towing a heavy trailer down a big hill)
Marketing
This is the answer, and the responses this thread is getting is proving how effective it is.
People think fancy brakes = shorter stopping distance even though that isn’t really true.
Unless you’re talking about the rear single piston brakes on some smaller cars I can’t think of one car that doesn’t have more than one piston calipers. I’ve never heard of one with less than two on the front.
My 2006 STI had 4 pistons in the front. This isn’t necessarily new tech.
Hi, big brake and racecar dork here. I feel compelled to add to this because I feel like the top answers are missing a degree of complexity in this.
While yes, in general, multi-piston calipers are going to provide more stopping power, it’s not quite as simple as heavier cars = need more brakes, therefore more pistons more brakes! My 3/4 ton pickup is heavier than any passenger car save maybe a model Y or a wagoneer, yet it has simply huge single piston brakes that will happily lock the tires up.
Brake torque is a function of pad mu, piston area, brake diameter, and the pressure generated by the master cylinder. The main advantage of multi-piston brakes is that you can more efficiently utilize the pad area for pistons. This leads to more even pad wear and more piston area for a given caliper size/diameter than you would otherwise manage. They are also much stiffer than single-piston calipers.
So, I have a couple of theories, as it’s hard to know exactly what decisions are being made behind closed doors.
First, for a given brake size and diameter, more piston area does improve the amount of brake torque generated per pedal effort at a given master cylinder size. I acknowledge that this is restating the whole “stops better” idea in a much more convoluted way; however I think part of the motivation is that at some point larger brakes get very heavy and unsprung weight is pretty awful for mileage and performance. Multi-piston brakes let them hit brake torque and feel targets without going with huge brakes.
Second, I think the feel aspect is likely the larger motivation. Like I said, you can spec huge single piston brakes that will absolutely still lock the tires up, but they won’t feel very good, and they’ll need a bunch of pedal effort due to the smaller piston area. Consumers of performance road cars simply don’t know much about what makes good brakes, and so the brakes feeling “grabby” is what they think good brakes feel like. Lots of piston area creates grabby brakes with short pedal travel without a ton of effort - this is the key thing in my estimation. The stiffer calipers also contribute to a stiffer and more confident pedal.
Finally, I really don’t think you should underestimate the appeal of big performance brakes under nice wheels. It’s one of the most obvious signals of a “performance” car, especially luxury cars that want to communicate fast but not overly flashy. That might be my bias, but I think that’s something people absolutely pick up on and it influences their opinion on the appearance.
Very well written! Great info.
Giant wheels, overly touchy/grabby brakes, over-sprung and under-damped suspension, there’s lots of attributes of modern “performance” cars that don’t do a damn thing for performance but people have somehow associated these visuals or feelings with it. Definitely makes me appreciate the approach Mazda took for the ND Miata in spite of all that
Multi piston hydraulic brakes are big in the mountain bike community and offer not just more braking capability but also the ability to feather the brakes better, improving what’s I’d call “braking accuracy. Simply put, if I only want to apply 20% of total braking capability I can do that by feel in a much more intuitive fashion
Yup, we call that “brake modulation” and on track cars that largely comes from the ability to use larger brake masters, lower mu pads, and stiffer calipers that all come with the multi-piston monoblocks. I sort of referred to this off hand when talking about how road cars actually are not set up for what real racing brakes require. In a race car you’ll actually find the pedals are pretty stiff and require a *lot* of effort, because it’s easier to modulate when the force spectrum is say 0-100 lbs as opposed to 0-20.
Heavier bigger cars. Engines with more power. My 16 Colorado is just as big and has just as much HP and more torque than my mom’s 99 f150. It can tow just as much as well.
Cars got heavier and cars share more parts. Really those two big things I think have led to the increase
weight
Lots of good answers already, one more is the increase in the size of wheels. Its hard to fit a multi-piston caliper inside a 93 civic’s 14” wheels