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Need more information. Post pics of the rotors with part numbers and year of your vehicle.
2014 E350 Don't have the part numbers as already on the car when I bought just yesterday.
The first pic is the passenger and the spiral holes are going with the rotation of the wheel which I think is incorrect. The highest holes contacts the pad first.
The second pic is the drivers side and the spiral pattern is going against the rotation. The highest holes contact the pad last.
I understand the confusion if any on my explanation. I hope I was somewhat clear.
Is this correct which I'm having a hard time phathoming?
Oh I'm not trying to argue just trying get clarification.
It looks like a left side rotor was used on the right side.
I have a M2 CS getting ready for the track for comparison. L/R
Notice the spiraling is consistent.
Both are interchangeable left and right but it would defeat the purpose. .
I could use two left side rotors and it would like what's on the Benz.
I find MB rotors hole-orientation weird too
Only 1 P/N on my rotor, can't order L or R version.
I do not know if a true AMG cars would be this weird too or not ?
I surely hope MB non AMG would set these rotors hole-orientation like your M2
I find MB rotors hole-orientation weird too
Only 1 P/N on my rotor, can't order L or R version.
I do not know if a true AMG cars would be this weird too or not ?
I surely hope MB non AMG would set these rotors hole-orientation like your M2
If this is the way MB do things fine. Just wanted to make sure someone didn't put to a left side rotor on the right side. And, I wasn't going nuts.
Ah dayum I guess I typed before I looked and did not think MB would be weird and have the same PN and rotor for both sides when drilled in spiral pattern.
Brembo Xtra discs are not directional. The hole pattern does not have a mandatory direction of rotation as it is designed to work correctly and deliver precisely the same performance and comfort irrespective of the side of the vehicle the disc is mounted on.
This is a solution that has been adopted in recent years by many carmakers for the sports versions of their road cars, as it allows the use of cross-drilled brake rotors to improve initial bite and disc cooling without having to use specific discs for the left and right hand sides.
Well, according to some race parts shops, if the vane is slanted like my rotor, direction of rotation will help better cooling.
But to how much cooler in a non race scenario ? Need a thermal gun and drive+brake the car hard.... LOL.
Above image, many shops are using as reference. I wonder who made it originally.
Also thermal gun is not accurate on shiny surfaces, need to know emissivity compensation.
This archive was from 16th May 2020.
REAR RIGHT, like 10-15 minutes after I enter the pit. Having fun at the race track and this is when my original MB-Akebono pads overheated during 16th and 25th May 2020 session.
I was more abusive on 25th May, because I got more familiar with the track. So 25th May was probably the brake pad killer.
FRONT RIGHT
Now both RIGHT side front and rear calipers, only calipers, I have thermocouple temperature sensors.
The idea was to log if my brake fluid ever got heated at the calipers, because I worried my piston seal can get damage.
Something like this heat-logger sticker for calipers. https://www.rogueengineering.com/Bre...Pair_p_22.html
Temperature Warnings
For those running fixed, multi-piston calipers (Brembo GT, for example), recommended working temperature is < 200°C (392F), whereas the maximum acceptable working temperature is 220°C (428F);
Over 240°C (464F), the seals fitted into the calipers can be overheated and they will not guarantee the right performances of the caliper (sealing, roll back, fluid absorption,…);
======
However, calipers itself are slow to heat up. Brake rotor heat first goes to the brake pad, a bit isolated by the thin double side tape of brake pad >> travel to the caliper pistons >>
>> heat up brake fluid inside calipers >> heat up calipers metal body>>> read by thermocouple.
Engine bay heat actually heat up front calipers more in a normal driving scenario but at traffic jam. 55C usually for front calipers.
I have not abused much my new under 3,000KM today, rotors and pads....yet. Soon, as my tires are now near 3 years old and still thick due to low mileage, I will bald them at the track before I buy new ones.
By then I can provide the calipers temperature data.
Bye bye brake pad. I did not realize this until next year March 2021. when I was inspecting it.
9,000KM old track overheated pads before being cleaned for better visual and a used 21,000KM pads removed from service in Oct 2019
I ended up re-using my 20,100KM old pads....LOL. When I got new front rotors, I use new brake pads for a fresh virgin start 100% new both rotors and pad.
To be clear, I don't care how the holes are oriented in relation to the rotation as long as it's the same for both sides. .
Does it make a difference, probably not. Vanes and brake cooling would be the bigger factor here. Although on an E series, I don't many of us are racing these things around.
This is probably done to lower costs.
Been racing cars and working on them for almost 30 years now and pick up on things like this.
To be clear, I don't care how the holes are oriented in relation to the rotation as long as it's the same for both sides. .
Does it make a difference, probably not. Vanes and brake cooling would be the bigger factor here. Although on an E series, I don't many of us are racing these things around.
This is probably done to lower costs.
Been racing cars and working on them for almost 30 years now and pick up on things like this.
IMHO, those holes are purely cosmetic. They slightly reduce the surface area of the brakes, and increase brakepad wear without any benefit (contrary to common belief, they do nothing for rotor cooling, far more air is moving from the inside to the outside of the rotor between the two disks). They don't do squat for cooling. you can in fact use the non-drilled rotors on a 'sport' E350 that came with the drilled rotors, as the brake calibers and pads are the same on both.
Is the left and right drilled rotors interchangeable?
The drivers looks correct but the passenger looks like it's reversed or the same as the drivers.
Is this correct?
Thank you.
I'm not a brake disk expert, just a mechanical engineer, but when I see something like the cross drilled or slotted disks it makes me think that why is this done to start with?
In hogger453's and S-Prihadi's pictures and the Brembo drawing we can see the holes. What is the "secret" of the hole patterns is that they overlap, i.e., every other row of holes is further away from the center.
A slotted disk does the same effect with just one slot, and I bet there are less slots that rows of holes in comparable brake disks.
Like LCG says, the holes (or slots) probably have very little to do with disk coolin though they may do "something" for that but the main purpose of the holes or slots IN MY OPINION is brake pad conditioning. The edge of a hole or a slot provides a microscopic "shaver" tool for the brake pad surface keeping them clean and this is why the hole pattern MUST overlap so the whole surface of the pad is cleaned. Slot, of course, provides a continuous edge across the pad so you can make only half of them compared to rows of holes to provide the same cleaning effect as holes.
Why make holes instead of slots? Again, IN MY OPINION, this is purely for saving money during manufacturing the disks. It is far faster to drill holes compared to machining the slots with an end mill or similar. Slots must be machines to provide the good quality edge thru the wear of the disk.
What comes to the inner fin direction, I don't think this has much to do other than for race cars it may where just a marginal cooling improvement can be critical.
Fins being in spiral shape may have more to do with preventing the warping of the disk.
I'm not a brake disk expert, just a mechanical engineer, but when I see something like the cross drilled or slotted disks it makes me think that why is this done to start with?
......
To start with, the road test proved those things to be efficient when race-style braking from speeds above 130 mph (200 kph).
Why they made it to luxury sedans? I think it is the culture, where sellers will brainwash customer to spend money on something they absolutely don't need. (vide AGM batteries).
Coming to the design, the holes suppose to improve venting and in result cooling of rotors. Not too many owners ever notice, but MB wheels do have venting holes in them as well. On my car with higher mileage, I found those holes completely plug with pads dust and other stuff. I drilled them clean during the service, but who does that?
The slots are design to shave glazed pads for better performance. You are sacrificing pad life for better performance. Again, it all happens if you brake from speeds above 130 mph...
All I was asking that if both side rotors were the same? That's all.
I prefer slotted rotors than over drilled. Drilled rotors actually cause more rotor and pad wear.
The hole or slots is where hot brake gases can escape. But honestly if your not carving the canyons or the track, it's meaningless.
I've raced long enough open and closed wheel to make up my own determination on pad and rotor wear.
All I was asking that if both side rotors were the same? That's all.
I prefer slotted rotors than over drilled. Drilled rotors actually cause more rotor and pad wear.
The hole or slots is where hot brake gases can escape. But honestly if your not carving the canyons or the track, it's meaningless.
I've raced long enough open and closed wheel to make up my own determination on pad and rotor wear.
Thank you.
Yet, you still don't understand that slots don't vent anything...
Alpha European Autotech here, uh so Mercedes only prints one rotor, it keeps parts cost down, the directional ones that Porsche produces are godawful expensive and you often run into a scenario where one of the two are out of stock. For example stocking two separate rotor part numbers would take twice as much infrastructure to produce, vs just making the one. If you drive a Porsche, buy the Pagid rotors and you save a ton of money and they're always available.
The direction of the holes actually makes no difference, in most scenarios except the extreme cases the holes barely make a difference, as for why it doesn't matter, it's because the discs are vaned symmetrically internally.
As for the comments about slotted rotors, I'm wearing the Powerstop extreme slotted rotors on the S550 5.5L, they bite hard but the noise has become sort of annoying over time and I'm over it. You hear a growling noise on the particularly hard stops. The slots don't cool, they "scrape" the pads and bite harder and the dust/hot gas have somewhere to go so the pad keeps biting. I've been told they're hard on pads but considering my ceramic Brembo pads have outlasted the OEM metallic compound (I use Pagid) by two sets so far, I'm ok with them as far as performance/longevity goes. Stick to the drilled ones honestly, and run a ceramic pad.
You gotta drive REAL fast to wonder what else is out there in terms of brake rotors. The OE mercedes design spec on these rotors are phenomenal and far far superior to the stupid ones BMW installs with the riveted-on aluminum hats which are a nightmare to procure if you dont know which ones to get and Mercedes braking force is often superior to actual supercars in my experience over the years. They don't mess around. I've installed the Girodisc rotors on the AMG cars and they're cool looking and they weigh much less but when my life is on the line and you drive triple digits fairly often, Zimmerman, Brembo, ATE, or Pagid every time. Zimmermans get a bad rap because the OE metallic compounds chew through them on the E and S class within 20k miles, but it's the pads, they have huge chunks of metal in them.
I can see that this would matter if the car was tracked. But considering that on a car like an E350, the drilled rotors serve very little purpose in cooling, and are mostly cosmetic, I wouldn't imagine that it is going to matter which way the drilled holes and vanes run.
When I was shopping for new rotors for my E350, I didn't see any of the brake companies who offered LH/RH drilled rotors. But I wasn't looking for it either.
05-12-2023 | 06:32 PM
when I was inspecting it.
