Tire Load rating
Thread Starter
Intermediate
Joined: Sep 2006
Posts: 39
Likes: 0
From: Harlington Bedfordshire
Tire Load rating
Greetings from the other side of the pond where I am having a little difficulty getting information as to the load rating of tires. I have no difficulty with size and speed rating but when I try and find the load rating (service rating) my manuals appear silent; as do a lot of the posts.
So, can you please help?. I need the load rating for a 1994 C4 convertible front tires 255x45x17. Some guides say have 98, some 95 and some 91. So which is it?
Thanks
Graham
So, can you please help?. I need the load rating for a 1994 C4 convertible front tires 255x45x17. Some guides say have 98, some 95 and some 91. So which is it?
Thanks
Graham
Team Owner
Joined: Sep 2003
Posts: 25,394
Likes: 2,741
Greetings from the other side of the pond where I am having a little difficulty getting information as to the load rating of tires. I have no difficulty with size and speed rating but when I try and find the load rating (service rating) my manuals appear silent; as do a lot of the posts.
So, can you please help?. I need the load rating for a 1994 C4 convertible front tires 255x45x17. Some guides say have 98, some 95 and some 91. So which is it?
Thanks
Graham
So, can you please help?. I need the load rating for a 1994 C4 convertible front tires 255x45x17. Some guides say have 98, some 95 and some 91. So which is it?
Thanks
Graham
Thread Starter
Intermediate
Joined: Sep 2006
Posts: 39
Likes: 0
From: Harlington Bedfordshire
Tire Load Rating
Many thanks for the prompt reply.
Please find attached a chart of tyre (tire) load ratings from which you will see what I am on about. Do I simply take the all up weight of my C4 convertible with 2 occupants and divide by 4 to get the load on each wheel and thus the load rating of the tire? Or, does anyone have a view on what load rating it should be for the front tires?
Thanks
Graham
Please find attached a chart of tyre (tire) load ratings from which you will see what I am on about. Do I simply take the all up weight of my C4 convertible with 2 occupants and divide by 4 to get the load on each wheel and thus the load rating of the tire? Or, does anyone have a view on what load rating it should be for the front tires?
Thanks
Graham
Le Mans Master
Joined: Aug 2015
Posts: 6,118
Likes: 1,994
From: St. Charles MO
In theory, since a C4 is close to 50/50 weight distribution, you could take the gross vehicle weight rating (this should be on a placard on the door frame and is different than the curb weight) and divide it by 4 to get the load range you need for your car. In practice, every 255/45/17 I see has a load range of at least 98 (750kg) and a couple have a range of 102 (850kg), all of which are waaaaaay more than your GVWR/4. Your C4's GVWR is probably a little less than 1850kg, and divide that by 4 and you'll see that the most load a single tire will ever see is around 213kg. Even during a 1G braking event, that will only double to 425kg, which is way less than any tire currently sold in your size. In other words, you really don't need to worry about load rating at all: every tire in that size is way over spec for a C4.
