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I also had to do an emergency braking from ~140 to ~80 mph because some retard changed lanes without looking in the rear view mirror.
That reminds me of a similar situation. Had a delivery van do this trying to overtake another delivery van, when I was coming up at around 150 mph on a slightly damp Autobahn. No fun if you feel the ABS come on at that speed. I had some choice words for him, but I managed to slow down in time. The brakes are actually impressive on this car and how it stays controllable and stable under hard braking, I have the standard brakes, now with the C63 Black Series Brembo full-floating rotors, so even better.
Whoaa 😵
What brakes are on yours? Carbon ceramic or standard red calipers?
I actually have the carbon ceramic. And to be honest I braked real hard at first (because his move "surprised" me) but the deceleration was higher than expected so I had enough room to let off the brake a little and enough time to express how I felt about him and his unnecessary move...
Originally Posted by superswiss
That reminds me of a similar situation. Had a delivery van do this trying to overtake another delivery van, when I was coming up at around 150 mph on a slightly damp Autobahn. No fun if you feel the ABS come on at that speed. I had some choice words for him, but I managed to slow down in time. The brakes are actually impressive on this car and how it stays controllable and stable under hard braking, I have the standard brakes, now with the C63 Black Series Brembo full-floating rotors, so even better.
I can absolutely agree to this statement - the brakes and the suspension setup really are amazing. I've owned a RS3 sedan before the AMG and it was a handful when you had to brake at high speeds. Hard (not emergency) braking in a slight corner at around 120mph actually gave me sweaty palms and wide open eyes because the rear end got very lively. That situation stayed very clearly in my mind and I was more than happy to see/feel that my new C63s is so stable and safe.
Hit 190 mph on straight & 155 twisties mountain road. Dead stable. I find that if your alignment out then this car won’t feel stable above 100mph. Also your tyres psi should be 40 if you going that fast.
im at 38 front and 36 rear. Which I feel like is a pretty good middle ground
I'm living in Germany and I'm driving a 2017 C63s sedan. If the traffic and road rules allow it I would say that 120 to 140 is a manageable cruising speed.
I've been doing 150mph on the Autobahn frequently and the car is absolutely stable. I also had to do an emergency braking from ~140 to ~80 mph because some retard changed lanes without looking in the rear view mirror. Even then the car was stable and felt safe. I've also been doing up to 180mph - of course you do feel the imperfections of the road way more intense when you're that fast but again the car was stable and I had no sweaty palms at all. My wife beside me was actually reading while I was doing around 170mph for several miles.
When going that fast I only suggest to switch the suspension to Sport (not Sport+) and of course make sure that the tire pressure is adjusted accordingly.
So with a 2 person occupancy with a set up of R19/20 and at speed over 155 mph, the tire pressure should be F:44 and R:39 ? And a 2 person occupancy with a set up of R19/20 at speed below 155 mph the tire pressure should be F: 33 R: 32 . I keep mine at F: 34 and R: 33.
So with a 2 person occupancy with a set up of R19/20 and at speed over 155 mph, the tire pressure should be F:44 and R:39 ? And a 2 person occupancy with a set up of R19/20 at speed below 155 mph the tire pressure should be F: 33 R: 32 . I keep mine at F: 34 and R: 33.
Yes, that's how it works. It all has to do with deflection. As the tire comes in contact with the road it bulges. How much it bulges has to do with how much load you put on it. More people and cargo in the car puts more load on the tire so it bulges more. The bulging creates a difference in the loaded radius of the tire vs. the unloaded radius. That difference is called deflection. This deflection or more specifically the bulging of the tire creates heat. The faster you drive the quicker the bulging occurs, so more heat is generated and if not controlled the tire will eventually overheat and the tread will separate and you know what follows then. So the cure to that is to increase tire pressure to reduce the amount of bulging and therefore reduce the amount of heat being generated. The more weight you load into the car and/or the faster you drive the more you need to reduce the bulging in order to avoid overheating, so the required tire pressure goes up with each. For occasional sprints above 155 mph or a short trip with a fully loaded car you don't necessarily need to increase your tire pressure as long as you keep an eye on the tire temperatures. Thankfully our cars have TPMS sensors that measure the temperature, so you can keep that up on the dash.
Given the traffic on the German Autobahn it was actually rare to go much above 155 mph, I opted for the lower tire pressures up to 155 mph and simply watched the tire temperatures if I went above 155. They very much started to heat up, but romps above 155 were generally short so they never reached dangerous levels and as soon as I lowered the speed, the tires cooled down again. Having a harsher ride that comes with the higher pressures wasn't worth putting up with given the short duration of speeds that required it.
An important other point is only do these fast speeds with intact tires. A repaired tire loses its speed ratings, so if you wanna keep driving fast, but get a nail or screw in the tire, don't get it patched, instead replace the tire or don't drive at these high speeds if you do get it patched.
Last edited by superswiss; Apr 5, 2021 at 01:05 AM.
I have 18s and my guide inside the door is different then that one
That's how it should be. It's also different between sedan, coupe and station wagon.
The post from superswiss explains why it needs to be different for different tire types/sizes and car types.
2020 s63 amg............2018 e63s amg w213............2017 C63s Coupe W205
Im glad this conversation went to tire pressure, because thats the most noticeable difference I have encountered. Top speed of 203, frequent general driving 90-110mph and commuting 70-90mph all in mexico of course. I run much lower tire pressures now than I did when I first purchased the vehicle. In stock form, I lowered the tire pressure from factory to 32-34 all around within 3 weeks of purchase. Anything over 36/37 made the vehicle feel loose and unstable. I hit a patch of grooves pavement going 70 and the car was out of control. Same patch after lowering pressure was totally normal. High speed driving on normal pavement had similar results. Coming from an f80 m3, the car just felt dangerous at high pressures. I have since installed KW HAS kit with a 1" drop and 20" wheels all around. The ride is obviously stiffer, but the car feels much more "planted" with the more aggressive camber and handles much better. Only downside is the faster tire wear, especially up front, but replacing tires is cost of business with this car. Aside from that, the only other issues I have encountered were with race mode, both before, and after stage 2 tune. The car would go into limp mode after "spirited" driving and would immediately need to pull over, cool and restart. Once I updated the factory ecm and retuned it, its been a non-issue.
BTW, the car speedometers typically read high. Can be 5-10% higher than actual speed. 5% is more typical with German cars at those speeds. Common radar detectors with GPS read about 10% higher, so for accurate speed you have to use a GPS speedometer that doesn't deliberately add a margin.
for what its worth, my modified c43 sedan with the c63s brake setup (390mm/360mm), c63 forged wheels with 255/35 and 285/30 michilin 4s feels extremely planted above 120 up to 183. Our rear suspension is same as c63 and front is different a bit due to awd. i would say the car is very confident and no problem reaching 150 with ease. i keep my tires at about 36-40 psi. I am not driving at those speeds for an extended period so i can't comment on curves or what not. but the brakes felt confident as well. If anything feels unstable, id check suspension, alignment, tires and brakes for wear or broken pieces. also on windy days car could feel more unstable if you are getting cross winds. at those speeds you are approaching jets take off speeds so wind speeds needs to be considered to some level for safe driving.
Im curious what everyone feels is a safe top speed before the rear end gets light and sketchy in our cars?
at what point do we need a bigger spoiler for more downforce?
I installed a Carbahn tune so my 120mph limiter is gone now....
He bought a tune to remove a 120 mph limiter that doesn't exist...
Im curious what everyone feels is a safe top speed before the rear end gets light and sketchy in our cars?
at what point do we need a bigger spoiler for more downforce?
I installed a Carbahn tune so my 120mph limiter is gone now....
Mine is limited to 174mph. The previous owner paid extra for the factory higher speed limit.
BTW, the car speedometers typically read high. Can be 5-10% higher than actual speed. 5% is more typical with German cars at those speeds. Common radar detectors with GPS read about 10% higher, so for accurate speed you have to use a GPS speedometer that doesn't deliberately add a margin.
Ive been thinking this forever. That I wasnt going as fast as the speedometer said
Yes, that's how it works. It all has to do with deflection. As the tire comes in contact with the road it bulges. How much it bulges has to do with how much load you put on it. More people and cargo in the car puts more load on the tire so it bulges more. The bulging creates a difference in the loaded radius of the tire vs. the unloaded radius. That difference is called deflection. This deflection or more specifically the bulging of the tire creates heat. The faster you drive the quicker the bulging occurs, so more heat is generated and if not controlled the tire will eventually overheat and the tread will separate and you know what follows then. So the cure to that is to increase tire pressure to reduce the amount of bulging and therefore reduce the amount of heat being generated. The more weight you load into the car and/or the faster you drive the more you need to reduce the bulging in order to avoid overheating, so the required tire pressure goes up with each. For occasional sprints above 155 mph or a short trip with a fully loaded car you don't necessarily need to increase your tire pressure as long as you keep an eye on the tire temperatures. Thankfully our cars have TPMS sensors that measure the temperature, so you can keep that up on the dash.
Given the traffic on the German Autobahn it was actually rare to go much above 155 mph, I opted for the lower tire pressures up to 155 mph and simply watched the tire temperatures if I went above 155. They very much started to heat up, but romps above 155 were generally short so they never reached dangerous levels and as soon as I lowered the speed, the tires cooled down again. Having a harsher ride that comes with the higher pressures wasn't worth putting up with given the short duration of speeds that required it.
An important other point is only do these fast speeds with intact tires. A repaired tire loses its speed ratings, so if you wanna keep driving fast, but get a nail or screw in the tire, don't get it patched, instead replace the tire or don't drive at these high speeds if you do get it patched.
how do you check the tire temp or is that something that was introduced in the facelift? I only see the air pressure on my screen
how do you check the tire temp or is that something that was introduced in the facelift? I only see the air pressure on my screen
They are shown along with the tire pressure, engine and transmission temp on the same screen complete with color coding of the tires and the powertrain. Not sure if this is new in the FL.
Driving that speed in rain or a drizzle with traffic? Totally insane in my book. Even if this clown is a professional driver, he is still putting other people's lives in danger!
Driving that speed in rain or a drizzle with traffic? Totally insane in my book. Even if this clown is a professional driver, he is still putting other people's lives in danger!
I'm guessing you've never been to Germany. This is absolutely normal over there and no big deal. Been there, done that many times. People in Germany understand that they need to stay on the right and expect fast traffic on the left. Occasionally, there is somebody who misjudges the speed of an oncoming car, but they quickly change back into the right lane if they see you approach in their rearview mirror. You certainly have to be alert no question. There's also no standing water on the German Autobahn like is very common in the USA. The asphalt is porous so that water drains. If you've never been to Germany and driven on the German Autobahn this is hard to comprehend. Consider that Germany has far smaller per capita fatal accident rate on the Autobahn than the USA has on their highway system with relatively low speed limits. Speed is often not the problem. The problem are distracted and poorly educated drivers, but it's more lucrative to issue speeding tickets than invest in the infrastructure and proper drivers education and training. It costs several thousand Euros to get a driver license in Germany and most of Europe and you have to attend mandatory classes. In Switzerland where I'm from for example and where we have speed limits on the Autobahn you get three chances to pass your road test, after the third time you have to go see a shrink to assess if you should be permanently banned from obtaining a driver license. It's just at a completely different level. Here in the USA every idiot gets a driver license and all they have to do is drive around the block and can just keep taking the road test until they pass. Many think driving is a right, even though it's clearly a privilege even here. What amazes me is that you can take the road test in most every language in the USA, even though the road signs are in English. There are people on the road that don't speak English, especially older generations and they have to be accompanied by their kids to the DMV so they can translate for them. Absolutely insane, IMO!
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