97v or 97y or 97H tires
06-29-2015, 06:39 AM
#2
Super Member
I would pay more attention to the weight load rating. I think the E550 has the XL load rating. As for how long tires last - that depends on a lot of variables, including the kind of driving and how often they are roated. I would say usually for OEM tires between 40,000 and 50,000. My wife's 2088 E350 had continental pro contacts OEM and they lasted about 60,000 miles.
06-29-2015, 09:25 AM
#3
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2012 E350 sedan
The last letter stands for speed rating
V, Y, and Z tires are high performance tires that usually have stiffer sidewalls and softer rubber for superior traction and cornering compared to an H tire. The harder rubber on H tires usually means much longer tire life compared to V, Y, and Z. H tires are usually less expensive too. Also, the car's suspension is tuned for using a high performance tire. Most casual drivers can tell the difference in cornering between an H tire and a high performance tire, but may not care because H tires usually have a softer ride.
Some tire stores will not sell you a lower speed rating tire, citing safety and/or liability concerns to try to scare you to a more expensive tire.
I just replaced the rear OEM Pirellis P Zero all season tires at 27K and they were done. I thought their snow performance was abysmal and they hydroplaned in heavy rain. Professional reviews by Tire Rack mirror my complaints. I went with the Continental DWS because they are the best all season tire in snow (I have a cabin in north Arizona) but some folks have had noise issues with them as they wore down. Scroll down to threads about replacement tire discussions
Last edited by VegasE; 06-29-2015 at 09:27 AM.
06-29-2015, 09:44 PM
#4
MBWorld Fanatic!
Check out grand touring tires such as the Bridgestone Turanza Serenity in a "W" rated tire. On my E500 I have the Goodyear Eagle Sport All Season and its handles well and very quiet.
06-29-2015, 10:14 PM
#5
NEVER downgrade the speed rating on a tire. The speed rating is not only for maximum speed, but also defines the strength of the tire. If MB fitted the vehicle and wheels with a V, then you need a minimum of V or higher. Never go lower. Of course you likely won't die from going lower, but it is generally good practice to not do it.
06-30-2015, 12:08 AM
#6
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2011 Mercedes Benz E550
Speed rating is important but tread wear rating is just important, the higher the number the harder the tire, the harder the tire the louder it is but will probably last longer, lower number has a softer ride but wont last as long
06-30-2015, 12:23 AM
#7
NEVER downgrade the speed rating on a tire. The speed rating is not only for maximum speed, but also defines the strength of the tire. If MB fitted the vehicle and wheels with a V, then you need a minimum of V or higher. Never go lower. Of course you likely won't die from going lower, but it is generally good practice to not do it.
Got a laugh out of that. Just wanted you to know... lol
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06-30-2015, 08:25 AM
#8
MBWorld Fanatic!
NEVER downgrade the speed rating on a tire. The speed rating is not only for maximum speed, but also defines the strength of the tire. If MB fitted the vehicle and wheels with a V, then you need a minimum of V or higher. Never go lower. Of course you likely won't die from going lower, but it is generally good practice to not do it.
It is true that the tire with higher speed rating can be stronger but you can also find that a tire from another manufacturer can be stronger for the side wall flex with a lower speed rating. As these cars come from the manufacturer they are equipped for the maximum speed just for the liability reasons.
06-30-2015, 11:07 AM
#9
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2012 E350 sedan
Agree
On these cars the letter for the tires speed rating is based on what these cars are made to drive, i.e. it is based on the maximum speed these cars can go on an Autobahn in Germany. For us it does not have much meaning as the speeds are so much lower.
It is true that the tire with higher speed rating can be stronger but you can also find that a tire from another manufacturer can be stronger for the side wall flex with a lower speed rating. As these cars come from the manufacturer they are equipped for the maximum speed just for the liability reasons.
It is true that the tire with higher speed rating can be stronger but you can also find that a tire from another manufacturer can be stronger for the side wall flex with a lower speed rating. As these cars come from the manufacturer they are equipped for the maximum speed just for the liability reasons.
That said, a car's suspension is tuned to be optimal for a narrow range of tires. Often, manufacturers have a tire specially made so the tire model you get as OEM is not identical to what you buy at your local tire store. As a practical matter, most folks can't tell the difference in handling between the OEM tire and some other quality tire.
The concept that buying a tire with lower speed rating is dangerous by definition is pure bull. You are perfectly safe from a speed perspective with any tire with a speed rating of 100mph or higher. As Arrie said, there are dramatic variations in sidewall flex and cornering performance among tires with identical sped ratings. The only thing speed rating implies is that a tire can be driven at the rated speed continuously without generating sufficient heat to cause a blowout. So buy a quality tire that meets your cornering and ride comfort requirements. Enthusiasts like myself will buy high performance tires because we like good handling and will take the car to those limits at times, but I would argue that the average driver could not tell much of a difference between an S-rated tire and a Z-rated tire except that most would think the Z tire had a stiffer ride.
06-30-2015, 07:15 PM
#10
On these cars the letter for the tires speed rating is based on what these cars are made to drive, i.e. it is based on the maximum speed these cars can go on an Autobahn in Germany. For us it does not have much meaning as the speeds are so much lower.
It is true that the tire with higher speed rating can be stronger but you can also find that a tire from another manufacturer can be stronger for the side wall flex with a lower speed rating. As these cars come from the manufacturer they are equipped for the maximum speed just for the liability reasons.
It is true that the tire with higher speed rating can be stronger but you can also find that a tire from another manufacturer can be stronger for the side wall flex with a lower speed rating. As these cars come from the manufacturer they are equipped for the maximum speed just for the liability reasons.
Munich's post was dead on. The most important factor is load rating. You get a tire with insufficient load rating and you risk a blow-out.
That said, a car's suspension is tuned to be optimal for a narrow range of tires. Often, manufacturers have a tire specially made so the tire model you get as OEM is not identical to what you buy at your local tire store. As a practical matter, most folks can't tell the difference in handling between the OEM tire and some other quality tire.
The concept that buying a tire with lower speed rating is dangerous by definition is pure bull. You are perfectly safe from a speed perspective with any tire with a speed rating of 100mph or higher. As Arrie said, there are dramatic variations in sidewall flex and cornering performance among tires with identical sped ratings. The only thing speed rating implies is that a tire can be driven at the rated speed continuously without generating sufficient heat to cause a blowout. So buy a quality tire that meets your cornering and ride comfort requirements. Enthusiasts like myself will buy high performance tires because we like good handling and will take the car to those limits at times, but I would argue that the average driver could not tell much of a difference between an S-rated tire and a Z-rated tire except that most would think the Z tire had a stiffer ride.
That said, a car's suspension is tuned to be optimal for a narrow range of tires. Often, manufacturers have a tire specially made so the tire model you get as OEM is not identical to what you buy at your local tire store. As a practical matter, most folks can't tell the difference in handling between the OEM tire and some other quality tire.
The concept that buying a tire with lower speed rating is dangerous by definition is pure bull. You are perfectly safe from a speed perspective with any tire with a speed rating of 100mph or higher. As Arrie said, there are dramatic variations in sidewall flex and cornering performance among tires with identical sped ratings. The only thing speed rating implies is that a tire can be driven at the rated speed continuously without generating sufficient heat to cause a blowout. So buy a quality tire that meets your cornering and ride comfort requirements. Enthusiasts like myself will buy high performance tires because we like good handling and will take the car to those limits at times, but I would argue that the average driver could not tell much of a difference between an S-rated tire and a Z-rated tire except that most would think the Z tire had a stiffer ride.
Even if two tires from two different manufacturers have different strength sidewalls, both tires are still qualified to go on your vehicle if they meet the designated speed rating. Doesn't mean you should go with the strongest version of the next lowest speed rating. So again, if the manufacturer puts a V on that car, that means that tire is designed to handle the maximum speed and weight of that vehicle with passengers. I would not put a lesser tire on the car even if I was only driving a max of 40 mph. But it's your car, do what you want.
Last edited by DJ Hellfire; 06-30-2015 at 07:19 PM.
06-30-2015, 10:02 PM
#11
MBWorld Fanatic!
Speed rating and load rating are practically directly related. A tire rated at lower speed will have a lower load rating and weaker sidewall that will buckle under high speeds and cornering quicker than a higher speed rated tire. And in fact, on older tires, these two ratings were combined into one rating (many years ago). Newer tires have them separated. Of course what I'm referring to is related to passenger tires only, not actual special grade load-bearing tires (classifies as C, D, or E range, etc).
Even if two tires from two different manufacturers have different strength sidewalls, both tires are still qualified to go on your vehicle if they meet the designated speed rating. Doesn't mean you should go with the strongest version of the next lowest speed rating. So again, if the manufacturer puts a V on that car, that means that tire is designed to handle the maximum speed and weight of that vehicle with passengers. I would not put a lesser tire on the car even if I was only driving a max of 40 mph. But it's your car, do what you want.
Even if two tires from two different manufacturers have different strength sidewalls, both tires are still qualified to go on your vehicle if they meet the designated speed rating. Doesn't mean you should go with the strongest version of the next lowest speed rating. So again, if the manufacturer puts a V on that car, that means that tire is designed to handle the maximum speed and weight of that vehicle with passengers. I would not put a lesser tire on the car even if I was only driving a max of 40 mph. But it's your car, do what you want.
Man, speed and load ratings on the tires are totally different things.
Load rating tells about the load the tire can carry. Load carrying comes from the air pressure inside the tire so the max load the tire can carry is based on the max pressure you can put inside the tire. This basically tells about the strength of the side wall of the tire, i.e. how much pressure the tire can take before it burst.
Speed rating is for the speed, i.e. how well the tire can hold against the centrifugal forces with high speed. This has nothing to do with the load rating. You can have the highest load rating tire but it could not be good at all for speed, like a common semi truck tire. These surely can carry load but none of them can go 130 mph without exploding under the centrifugal forces generated by the speed.
06-30-2015, 10:20 PM
#12
MBWorld Fanatic!
Man, speed and load ratings on the tires are totally different things.
Load rating tells about the load the tire can carry. Load carrying comes from the air pressure inside the tire so the max load the tire can carry is based on the max pressure you can put inside the tire. This basically tells about the strength of the side wall of the tire, i.e. how much pressure the tire can take before it burst.
Speed rating is for the speed, i.e. how well the tire can hold against the centrifugal forces with high speed. This has nothing to do with the load rating. You can have the highest load rating tire but it could not be good at all for speed, like a common semi truck tire. These surely can carry load but none of them can go 130 mph without exploding under the centrifugal forces generated by the speed.
Load rating tells about the load the tire can carry. Load carrying comes from the air pressure inside the tire so the max load the tire can carry is based on the max pressure you can put inside the tire. This basically tells about the strength of the side wall of the tire, i.e. how much pressure the tire can take before it burst.
Speed rating is for the speed, i.e. how well the tire can hold against the centrifugal forces with high speed. This has nothing to do with the load rating. You can have the highest load rating tire but it could not be good at all for speed, like a common semi truck tire. These surely can carry load but none of them can go 130 mph without exploding under the centrifugal forces generated by the speed.
+1
07-01-2015, 06:03 AM
#14
First, I did not say they were the same thing. I said they were related. A tire with a higher speed rating will in face be a stronger tire with a stronger side wall and be able to support more of a load. This is a fact.
As I stated in my post above, I am not referring to load bearing truck tires. No one would put them on a passenger sports vehicle and it is a completely different subject. Regardless, all tires have this rating and it will be higher on passenger tires with higher speed ratings, or at minimum, meet the manufacturers requirements for both load and speed.
You are missing the point. That is that SPEED is not the only factor in the choice of tire speed rating for a car. Strength/Load is also considered. You are not going to have a high speed rated tire that is not strong enough to support the speed and load and cornering of the vehicle, nor would any manufacturer choose a tire like this. And regardless of the speed you drive, you want to ensure you have a tire that will fully support the weight of the vehicle properly, especially when cornering hard. Choosing tire with a lower speed rating just to save a few bucks because you don't drive 150 mph is not the way to do that.
Load rating tells about the load the tire can carry. Load carrying comes from the air pressure inside the tire so the max load the tire can carry is based on the max pressure you can put inside the tire. This basically tells about the strength of the side wall of the tire, i.e. how much pressure the tire can take before it burst.
Speed rating and load rating are practically directly related. A tire rated at lower speed will have a lower load rating and weaker sidewall that will buckle under high speeds and cornering quicker than a higher speed rated tire. And in fact, on older tires, these two ratings were combined into one rating (many years ago). Newer tires have them separated. Of course what I'm referring to is related to passenger tires only, not actual special grade load-bearing tires (classified as C, D, or E range, etc).
Speed rating is for the speed, i.e. how well the tire can hold against the centrifugal forces with high speed. This has nothing to do with the load rating. You can have the highest load rating tire but it could not be good at all for speed, like a common semi truck tire. These surely can carry load but none of them can go 130 mph without exploding under the centrifugal forces generated by the speed.
You are missing the point. That is that SPEED is not the only factor in the choice of tire speed rating for a car. Strength/Load is also considered. You are not going to have a high speed rated tire that is not strong enough to support the speed and load and cornering of the vehicle, nor would any manufacturer choose a tire like this. And regardless of the speed you drive, you want to ensure you have a tire that will fully support the weight of the vehicle properly, especially when cornering hard. Choosing tire with a lower speed rating just to save a few bucks because you don't drive 150 mph is not the way to do that.
Last edited by DJ Hellfire; 07-01-2015 at 06:42 PM.
07-01-2015, 03:51 PM
#15
Super Member
I just replaced my OEM rubber with a XL rated set featuring a speed rating of V or 149mph.
I wouldn't have flinched if they had a lower speed rating but maintained the XL load rating. IIRC, non-AMG cars in NA are limited to ~130mph.
For those that don't want to take a suspect physics course online, I recommend you instead hit up a knowledgeable source for tire research before buying anything. Check out tirerack.com or a local shop.
http://www.tirerack.com/tires/tirete....jsp?techid=35
I wouldn't have flinched if they had a lower speed rating but maintained the XL load rating. IIRC, non-AMG cars in NA are limited to ~130mph.
For those that don't want to take a suspect physics course online, I recommend you instead hit up a knowledgeable source for tire research before buying anything. Check out tirerack.com or a local shop.
http://www.tirerack.com/tires/tirete....jsp?techid=35
Last edited by Johnny Rad; 07-01-2015 at 03:53 PM.
07-01-2015, 11:34 PM
#16
MBWorld Fanatic!
First, I did not say they were the same thing. I said they were related. A tire with a higher speed rating will in face be a stronger tire with a stronger side wall and be able to support more of a load. This is a fact.
As I stated in my post above, I am not referring to load bearing truck tires. No one would put them on a passenger sports vehicle and it is a completely different subject. Regardless, all tires have this rating and it will be higher on passenger tires with higher speed ratings, or at minimum, meet the manufacturers requirements for both load and speed.
You are missing the point. That is that SPEED is not the only factor in the choice of tire speed rating for a car. Strength/Load is also considered. You are not going to have a high speed rated tire that is not strong enough to support the speed and load and cornering of the vehicle, nor would any manufacturer choose a tire like this. And regardless of the speed you drive, you want to ensure you have a tire that will fully support the weight of the vehicle properly, especially when cornering hard. Choosing tire with a lower speed rating just to save a few bucks because you don't drive 150 mph is not the way to do that.
As I stated in my post above, I am not referring to load bearing truck tires. No one would put them on a passenger sports vehicle and it is a completely different subject. Regardless, all tires have this rating and it will be higher on passenger tires with higher speed ratings, or at minimum, meet the manufacturers requirements for both load and speed.
You are missing the point. That is that SPEED is not the only factor in the choice of tire speed rating for a car. Strength/Load is also considered. You are not going to have a high speed rated tire that is not strong enough to support the speed and load and cornering of the vehicle, nor would any manufacturer choose a tire like this. And regardless of the speed you drive, you want to ensure you have a tire that will fully support the weight of the vehicle properly, especially when cornering hard. Choosing tire with a lower speed rating just to save a few bucks because you don't drive 150 mph is not the way to do that.
You also need to think about the fact that tire makers post a load rating and a speed rating separately. Reason for this is that they really are two different things.
For your info, the main component of the tire`s speed rating comes from the strength of the belt and not the side walls. It is true that tires rated for faster speeds often also have stronger side walls but not always especially with some budget tires that sell with strong belts for speed but are pure trash for other properties.
Last edited by Arrie; 07-01-2015 at 11:36 PM.
07-02-2015, 05:47 PM
#17
1. You also need to think about the fact that tire makers post a load rating and a speed rating separately. Reason for this is that they really are two different things.
2. For your info, the main component of the tire`s speed rating comes from the strength of the belt and not the side walls. It is true that tires rated for faster speeds often also have stronger side walls but not always especially with some budget tires that sell with strong belts for speed but are pure trash for other properties.
2. For your info, the main component of the tire`s speed rating comes from the strength of the belt and not the side walls. It is true that tires rated for faster speeds often also have stronger side walls but not always especially with some budget tires that sell with strong belts for speed but are pure trash for other properties.
1. Again, these two ratings were once combined in one on older tires. They are only separated on more modern tires. They are still related whether separate or not.
2. Again, the strength of sidewall on an expensive tire vs a budget tire of the same speed rating is irrelevant. The point I'm making is (and always was) that a tire that matches the speed rating the manufacturer specifies will meet the strength requirements of the vehicle. Doesn't matter if the tire is expensive or cheap, the proper rating will ensure that either tire is qualified for the vehicle beyond any shadow of doubt and you should not downgrade that rating, period.
07-03-2015, 10:10 PM
#18
MBWorld Fanatic!
This explains load and speed ratings. I worked for Goodyear Tire and Rubber Co. for several years and in my opinion this link best explains the ratings.
http://www.tirerack.com/tires/tirete....jsp?techid=35
http://www.tirerack.com/tires/tirete....jsp?techid=35
07-03-2015, 11:47 PM
#19
MBWorld Fanatic!
1. Again, these two ratings were once combined in one on older tires. They are only separated on more modern tires. They are still related whether separate or not.
2. Again, the strength of sidewall on an expensive tire vs a budget tire of the same speed rating is irrelevant. The point I'm making is (and always was) that a tire that matches the speed rating the manufacturer specifies will meet the strength requirements of the vehicle. Doesn't matter if the tire is expensive or cheap, the proper rating will ensure that either tire is qualified for the vehicle beyond any shadow of doubt and you should not downgrade that rating, period.
2. Again, the strength of sidewall on an expensive tire vs a budget tire of the same speed rating is irrelevant. The point I'm making is (and always was) that a tire that matches the speed rating the manufacturer specifies will meet the strength requirements of the vehicle. Doesn't matter if the tire is expensive or cheap, the proper rating will ensure that either tire is qualified for the vehicle beyond any shadow of doubt and you should not downgrade that rating, period.
My car came from the factory with all season Pirelli P Zero Nero 245/40R18 97V XL tires. Speed rating V (149 mph), load rating 97 (1609 lbs).
By your logic I could go and buy tires from Tire Rack that are: All season Contiprocontact 245/40R18 93V , i.e. speed rating the same as the OEM tires but load index only 93 (1433 lbs).
Would you install these under your car? I certainly would not as I think it is more important to maintain the load index here in the U.S. as the lowest speed rating is high enough for our speeds.
07-05-2015, 04:37 PM
#20
My car came from the factory with all season Pirelli P Zero Nero 245/40R18 97V XL tires. Speed rating V (149 mph), load rating 97 (1609 lbs).
By your logic I could go and buy tires from Tire Rack that are: All season Contiprocontact 245/40R18 93V , i.e. speed rating the same as the OEM tires but load index only 93 (1433 lbs).
Would you install these under your car? I certainly would not as I think it is more important to maintain the load index here in the U.S. as the lowest speed rating is high enough for our speeds.
By your logic I could go and buy tires from Tire Rack that are: All season Contiprocontact 245/40R18 93V , i.e. speed rating the same as the OEM tires but load index only 93 (1433 lbs).
Would you install these under your car? I certainly would not as I think it is more important to maintain the load index here in the U.S. as the lowest speed rating is high enough for our speeds.
07-05-2015, 06:16 PM
#21
MBWorld Fanatic!
Yes I would install them on my car because the speed rating matches what the manufacturer recommends. Just because the Conti has a lower load index doesn't mean that load index is not qualified for the vehicle. It just means it's not as strong as the more expensive Nero. You're always gonna have comparable tires that will not have the exact same specs even though they all may meet the manufacturers requirements.
So you go with the speed rating that has no meaning in U.S. but will install lower load rating tires on car. I think it would make more sense to follow the load rating and let speed rating be what ever they come with unless you plan on doing some heavy speeding on our roads.
07-06-2015, 07:02 AM
#22
So you go with the speed rating that has no meaning in U.S. but will install lower load rating tires on car. I think it would make more sense to follow the load rating and let speed rating be what ever they come with unless you plan on doing some heavy speeding on our roads.
Now of course, the vehicle may be available with optional wheels that do come with lower speed ratings or they may offer other tire choices from factory (summer or all season) that you may be able to get away with by matching those ratings. But I personally would just rather match or exceed what came on the car.
Last edited by DJ Hellfire; 07-06-2015 at 07:05 AM.
07-06-2015, 10:56 AM
#23
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2014 E550-sold 😩
My car came from the factory with all season Pirelli P Zero Nero 245/40R18 97V XL tires. Speed rating V (149 mph), load rating 97 (1609 lbs).
By your logic I could go and buy tires from Tire Rack that are: All season Contiprocontact 245/40R18 93V , i.e. speed rating the same as the OEM tires but load index only 93 (1433 lbs).
Would you install these under your car? I certainly would not as I think it is more important to maintain the load index here in the U.S. as the lowest speed rating is high enough for our speeds.
By your logic I could go and buy tires from Tire Rack that are: All season Contiprocontact 245/40R18 93V , i.e. speed rating the same as the OEM tires but load index only 93 (1433 lbs).
Would you install these under your car? I certainly would not as I think it is more important to maintain the load index here in the U.S. as the lowest speed rating is high enough for our speeds.
In any event, I'm on the side of a load rated tire as opposed to speed rated. I have the ControlContact Sport AS, which is a 97Y XL tire and good to 186 mph as well. I have only been to 185, so I'm ok.
Last edited by KEY08; 07-06-2015 at 11:21 AM.
07-07-2015, 04:49 PM
#24
MBWorld Fanatic!
Load rating is FAR more important than speed rating. Buying a speed rated tire does not ensure the load rating will be proper.
For Example
I can buy BFG g-Force R1 S or Hoozier R7 in 245/40/ZR18 with an 88W (speed rating 186MPH and a light load of 1235lbs.) These do not meet the recommended load index for our cars load index of 97 (1609lbs) and up.
An E550 has a curb weight of 4400lbs add passengers and luggage (manual indcates up to 1400lbs of additional weight as an example, but B-pillar indicates about 900) and your pushing 5300-5800lbs which exceeds 1235lbs X4 = 4940lbs the 88W tires provided. To make this worse the car is most overloaded and tires prone to failure at high speeds.
Things get even worse if your running 19"+ wheels & tires. This example used stock 245/40/18 tires if you're running aftermarket wheels in 19+ the load index usually decreases with the loss of sidewall. A Michelin PSS 245/40/18 has a 97 load rating 245/35/19 is 93 and a 245/30/20 is only 90 - all are 186MPH Y rated. I'm sure some other tires have even lower loads in these sizes.
For those that don't know extra load XL tires (commonly used) achieve their max load at 41PSI whereas traditional load tires reach their at 35PSI. As tire pressure decreases below these thresholds so too does their load index.
OK - so 4 97Y rated tires can carry 1609x4=6436lbs which is far in excess of what an E might really weigh fully loaded down. Basically Mercedes are over-engineered and that's fine by me. That is the max a tire is rated for and things like negative camber and other variables can lower the limit. The 1609lbs is also on each tire and hills, potholes, cornering can put a greater % of the weight on a given wheel than just 25%.
Be safe out there.
For Example
I can buy BFG g-Force R1 S or Hoozier R7 in 245/40/ZR18 with an 88W (speed rating 186MPH and a light load of 1235lbs.) These do not meet the recommended load index for our cars load index of 97 (1609lbs) and up.
An E550 has a curb weight of 4400lbs add passengers and luggage (manual indcates up to 1400lbs of additional weight as an example, but B-pillar indicates about 900) and your pushing 5300-5800lbs which exceeds 1235lbs X4 = 4940lbs the 88W tires provided. To make this worse the car is most overloaded and tires prone to failure at high speeds.
Things get even worse if your running 19"+ wheels & tires. This example used stock 245/40/18 tires if you're running aftermarket wheels in 19+ the load index usually decreases with the loss of sidewall. A Michelin PSS 245/40/18 has a 97 load rating 245/35/19 is 93 and a 245/30/20 is only 90 - all are 186MPH Y rated. I'm sure some other tires have even lower loads in these sizes.
For those that don't know extra load XL tires (commonly used) achieve their max load at 41PSI whereas traditional load tires reach their at 35PSI. As tire pressure decreases below these thresholds so too does their load index.
OK - so 4 97Y rated tires can carry 1609x4=6436lbs which is far in excess of what an E might really weigh fully loaded down. Basically Mercedes are over-engineered and that's fine by me. That is the max a tire is rated for and things like negative camber and other variables can lower the limit. The 1609lbs is also on each tire and hills, potholes, cornering can put a greater % of the weight on a given wheel than just 25%.
Be safe out there.
07-07-2015, 05:54 PM
#25
MBWorld Fanatic!
Load rating is FAR more important than speed rating. Buying a speed rated tire does not ensure the load rating will be proper.
For Example
I can buy BFG g-Force R1 S or Hoozier R7 in 245/40/ZR18 with an 88W (speed rating 186MPH and a light load of 1235lbs.) These do not meet the recommended load index for our cars load index of 97 (1609lbs) and up.
An E550 has a curb weight of 4400lbs add passengers and luggage (manual indcates up to 1400lbs of additional weight as an example, but B-pillar indicates about 900) and your pushing 5300-5800lbs which exceeds 1235lbs X4 = 4940lbs the 88W tires provided. To make this worse the car is most overloaded and tires prone to failure at high speeds.
Things get even worse if your running 19"+ wheels & tires. This example used stock 245/40/18 tires if you're running aftermarket wheels in 19+ the load index usually decreases with the loss of sidewall. A Michelin PSS 245/40/18 has a 97 load rating 245/35/19 is 93 and a 245/30/20 is only 90 - all are 186MPH Y rated. I'm sure some other tires have even lower loads in these sizes.
For those that don't know extra load XL tires (commonly used) achieve their max load at 41PSI whereas traditional load tires reach their at 35PSI. As tire pressure decreases below these thresholds so too does their load index.
OK - so 4 97Y rated tires can carry 1609x4=6436lbs which is far in excess of what an E might really weigh fully loaded down. Basically Mercedes are over-engineered and that's fine by me. That is the max a tire is rated for and things like negative camber and other variables can lower the limit. The 1609lbs is also on each tire and hills, potholes, cornering can put a greater % of the weight on a given wheel than just 25%.
Be safe out there.
For Example
I can buy BFG g-Force R1 S or Hoozier R7 in 245/40/ZR18 with an 88W (speed rating 186MPH and a light load of 1235lbs.) These do not meet the recommended load index for our cars load index of 97 (1609lbs) and up.
An E550 has a curb weight of 4400lbs add passengers and luggage (manual indcates up to 1400lbs of additional weight as an example, but B-pillar indicates about 900) and your pushing 5300-5800lbs which exceeds 1235lbs X4 = 4940lbs the 88W tires provided. To make this worse the car is most overloaded and tires prone to failure at high speeds.
Things get even worse if your running 19"+ wheels & tires. This example used stock 245/40/18 tires if you're running aftermarket wheels in 19+ the load index usually decreases with the loss of sidewall. A Michelin PSS 245/40/18 has a 97 load rating 245/35/19 is 93 and a 245/30/20 is only 90 - all are 186MPH Y rated. I'm sure some other tires have even lower loads in these sizes.
For those that don't know extra load XL tires (commonly used) achieve their max load at 41PSI whereas traditional load tires reach their at 35PSI. As tire pressure decreases below these thresholds so too does their load index.
OK - so 4 97Y rated tires can carry 1609x4=6436lbs which is far in excess of what an E might really weigh fully loaded down. Basically Mercedes are over-engineered and that's fine by me. That is the max a tire is rated for and things like negative camber and other variables can lower the limit. The 1609lbs is also on each tire and hills, potholes, cornering can put a greater % of the weight on a given wheel than just 25%.
Be safe out there.
Thank You very much for your post!!!
