Hey all,

I did a search looking for speed ratings on tires, and going over them. My arctic alpins have a max of 160km's which is around 100 miles an hour i think?

Speed Rating - Miles/Hour - Kilometers/Hour - Typical Use N=87 MPH, 140km/h, Spare Tires U=124 MPH, 200km/h
P=93 MPH, 150km/h H=130 MPH, 210km/h, Sport Sedans
Q=99 MPH, 160km/h, Winter, LT Tires V=149 MPH, 240km/h, Sports Cars
R=106 MPH, 170km/h, LT Tires Z=149 MPH, 240km/h and over, Sports Cars
S=112 MPH, 180km/h W=168 MPH, 270km/h, Exotic Sport Cars
T=118 MPH, 190km/h Y=186 MPH, 300km/h, Exotic Sport Cars

Sometimes late night i just burn it down a highway thats brand new, extremely flat, and usualy always empty. I reach 160km's which is the tires speed rating and never go higher. If i did decide to go above the intended rating. For how long could i do it for? like if i decided to try out 200km's/124 miles an hour with these tires. For how long could i do it for, if at all?

Not that i'm intending to do this on winter tires, mainly i'm just curious if did could go over 160 without worrying.

In my search of the board i read some peoples threads who wrote 10 minutes, 10 miles, 1 hour. Which is the actual number?


Thanks a bunch

 

there is no actual number. It's very subjective and depends on factors such as inflation pressure, ambient temperature, vehicle loading, tire condition, etc...

 

I wouldn't exceed the rated speed at all. At high speeds, there is a tremendous amount of stress on the tire. If you get separation of the tread (which I think is what the tire max speed is rated against)at high speed , you could lose control.

 

the speed rating is how long a tire at optimal inflation and such can maintain that speed for 2 HOURS. so ya your safe for like 10-20mph.

 

you mean i'd be able to go 10-20 mph safely above the tire rating?

or, i can go 10-20 mph above (in my case) 160mph for about 2 hours.

 

yeah, those speed ratings are for maximum *sustained* speed. So if you go over for a short period of time they should be fine. Just be sure your tires are inflated properly. If you drive on the highway a lot you might want to boost the tire pressure 2-4 psi above the normal rating. This will make the tire "harder" and have a smaller rolling resistance which will help prevent heat buildup.

 

The rating is designed with regards to the heat a tire is exposed to at whatever rated speed, for a certain amount of time. I thought it was for one hour, but someone else said two. Either way, as long as you aren't going 140 on the autobahn on tires rated at 110 for any period of time you should be fine, but you take a risk at any speed. I've gone 130-140 many times on my winter tires (not snow tires), I don't even know what they are rated at. I'd guess S rating.

 

An interesting note...

My mom drives a GS400. In the owners manual it says to add 10psi to the tires when you will be sustaining speeds over 100mph for long periods.

 

That's why I ride at about 40 psi on my 18's