I find myself in the happy position of being able to justify a new set of boots. I love tyre shopping.

I'm planning to go for 245/70 17 in an AT pattern.

However, I have found that the tyres I'm looking at have speed ratings of R, S, or T. That's quite a way from the H rating of my current tyres. The patterns I most like are only R rated. Indeed, one is Q rated, but I'm not prepared to go that low.

Do you have experience with tyres with these low maximum speed ratings? They are legal to run here, so that's not a consideration.

What is the max speed of the diesels?

All opinions welcome. MY11 SD4 SE Auto

SD4 has a top speed of 118 mph. Tyres should have a greater capability of speed to allow margin of safety.

From AA:
What’s a tyre speed rating?
The speed rating of a tyre shows you the top speed that the tyre can safely be driven at. It’s a legally approved limit and tyres are only rated after they’ve been tested in a lab. The safest top speed applies as long as the tyre isn’t being driven with too much weight loaded.

Often, the tyre speed rating will be a faster speed than your car's able to go. That’s mainly for safety reasons, to make sure that you tyre performance is never worse than the car’s performance.

Find out more about tyre law.


Does the tyre speed rating matter?
Choosing the right tyre speed rating for your car’s important for the safety of yourself and other road users.

If the tyre speed rating’s too low for your car, it might not be able to cope with the heat of high speeds. That could cause the tyre to lose performance and the car to lose control. It could even lead to a tyre blow-out.

But it’s not just about speed. The rating also relates to:

Ride comfort
Tread wear
Traction
Cornering ability
It’s important to choose the right speed rating for your vehicle and the conditions. Tyres with higher speed ratings may give better grip and stopping distances, but they might not perform as well in the cold and could wear out faster.

Tyre speed rating and insurance
The tyre speed rating’s also important for legal reasons. If you have a lower tyre speed rating than you should, it might invalidate your car insurance.


Where can I find the tyre speed rating?
You can check the tyre speed rating on the sidewall of a car. There's a group of letters and numbers on the side. The final letter is the speed rating.

The speed rating letter comes after the load rating. It’s important to look at both together because the speed rating depends on driving with the right load Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

118 mph! Who'd have thought. That's torn it - 190 km/h - that's a T rating tyre. Really cuts down the options. , because I must use a tyre with a speed rating equal to or higher than the max speed of the vehicle - which makes sense.

I just hope that I have such an emergency I can try the Freeo at 190. Could be fun. Or interesting.

Thanks Bob.


Keep voting folks. MY11 SD4 SE Auto

90 vs 140kph you are using twice the fuel & in NT you will not reach the next petrol station.

It's why everyone is driving 90 to 100 in the outback. Then factor in headwinds (going from QLD to NT there is a sign headwinds increase fuel consumption, it's 471km from Camooweal to Tennant Creek & you really do not want to run out of fuel).

A lot of 4WDs are using LT (light truck) tyres because our roads eat tyres for breakfast & both your spares for morning tea! I doubt LT tyres have a high speed rating. Procrastination, mankind's greatest labour saving device!

Acoustic insulation ARB TPMS 3xARB air compressors After cooler Air tank On-board OCD pressure air/water cleaning Additional 50L fuel Carpet in doors ABE 2x1kg Waeco 28L modified fridge Battery 4x26ah Solar 120w Victron MPPT 100/20 DC-DC 18amps 175amp jumper plug Awning 6x255/60R18

If it’s not illegal there to use a tyre with a lower rating than the vehicle (sounds stupid to me that legislation) and your sure you will be driving always within the rating, go for it I guess…….it’s your funeral

 Regards

David

Lovely i6 has now gone, but not me......

Please let me know if anything in my post offends you, as I may wish to offend you again......

Not illegal no but an insurance company may take a different view in the event of a claim. Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

Very possibly…..of course before fitting they could always ask. Regards

David

Lovely i6 has now gone, but not me......

Please let me know if anything in my post offends you, as I may wish to offend you again......

Boxbrownie wrote:

If it’s not illegal there to use a tyre with a lower rating than the vehicle (sounds stupid to me that legislation) and your sure you will be driving always within the rating, go for it I guess…….it’s your funeral

That’s better, I couldn’t understand why the AusGov would let you get away with that, and they don’t

Thanks for the clarification. Regards

David

Lovely i6 has now gone, but not me......

Please let me know if anything in my post offends you, as I may wish to offend you again......

If you have ever been it the outback cars without poodle rims are using LT tyres.

As far as car registration my mechanic over the decades uses his hand to create the braking deceleration rate & if not too much smoke come out of the exhaust to worry about it's not an issue & this is NSW. I could upgrade my brakes to leather & it's ok in NSW.


This is a road registered car outside NSW, it doesn't matter what tyre you have on the car as long as it has 1psi of air in it. Quite frankly I have seen worse road registered cars in central Australia, but it was life threatening to take a photo.

Click image to enlarge