Tyre speed rating
Discussion
I thought I had understood the speed rating until I read the excerpt below from Toyos web site.
Let's use the Proxes T1-S 265/40ZR17 96Y above as an example
Proxes T1-S- The Toyo pattern name.
265 - The nominal section width of the tyre in millimetres.
40 - The aspect ratio of the tyre, (the ratio between the section height and section width). If no figure is shown it is normally 82.
R - Radial construction. All Toyo’s car tyres sold in the UK are radial except for certain special tyres such as space saver spares.
17 - The diameter of the rim shown in inches.
96 - The load capacity of the tyre shown as an index. which should be looked up on the load index scale table here. In this case the load capacity of the tyre at the correct inflation pressure is 710kg.
Y - The speed symbol, i.e. the maximum sustainable speed for the tyre at the load capacity given - in this case 186.4mph. View the Speed Table here
SYMBOL GUIDE (NORMAL USE)
SYMBOL-SPEED (kph)- SPEED (mph)
S 180 111.8
T 190 118.1
U 200 124.3
H 210 130.5
V 240 149.1
W 270 167.8
Y 300 186.4
VR* 210+ 130+
ZR* 240+ 150+
Now my tyres are Toyo Proxes
T1S 225/50ZR15 91W and T1R 245/45ZR16 94W
According to the example given above by Toyo, this makes them rated for 167.8 mph. I thought the ZR in the middle rated them at 150 +
They will need changing soon, and I face the perennial problem of correct size and speed rating, so I want to understand what I have got at the moment.
Can anyone enlighten me please?
Let's use the Proxes T1-S 265/40ZR17 96Y above as an example
Proxes T1-S- The Toyo pattern name.
265 - The nominal section width of the tyre in millimetres.
40 - The aspect ratio of the tyre, (the ratio between the section height and section width). If no figure is shown it is normally 82.
R - Radial construction. All Toyo’s car tyres sold in the UK are radial except for certain special tyres such as space saver spares.
17 - The diameter of the rim shown in inches.
96 - The load capacity of the tyre shown as an index. which should be looked up on the load index scale table here. In this case the load capacity of the tyre at the correct inflation pressure is 710kg.
Y - The speed symbol, i.e. the maximum sustainable speed for the tyre at the load capacity given - in this case 186.4mph. View the Speed Table here
SYMBOL GUIDE (NORMAL USE)
SYMBOL-SPEED (kph)- SPEED (mph)
S 180 111.8
T 190 118.1
U 200 124.3
H 210 130.5
V 240 149.1
W 270 167.8
Y 300 186.4
VR* 210+ 130+
ZR* 240+ 150+
Now my tyres are Toyo Proxes
T1S 225/50ZR15 91W and T1R 245/45ZR16 94W
According to the example given above by Toyo, this makes them rated for 167.8 mph. I thought the ZR in the middle rated them at 150 +
They will need changing soon, and I face the perennial problem of correct size and speed rating, so I want to understand what I have got at the moment.
Can anyone enlighten me please?
Edited by WokingWedger on Friday 21st November 08:10
Edited by WokingWedger on Friday 21st November 08:11
Not absolutely sure, but as ZR is an old rating of 150+, and W is a newer rating of 167max, then they could both be correct, with the W being the most important part. If I remember in olden times, the rating was where you have the ZR, but they now do in at then end where the W is.
Of course it could mean that you need to keep the between 150 and 167 
Of course it could mean that you need to keep the between 150 and 167 Gassing Station | Chimaera | Top of Page | What's New | My Stuff