Tyres fuel rating

beyond the blue · June 9, 2023

I've never really studied tyres in the past, but having read a few threads about them I looked up the rating of my Dunlop SP Sport Maxx 050 and it shows 'D' for the fuel economy. What would be the difference between 'A' & 'E' is it minimal or substantial?

ColinBarber · June 9, 2023

There is around 1.5 to 2% difference in fuel economy per grade but is dependent on the average speed.

Steven C · June 9, 2023

2 hours ago, beyond the blue said:

I've never really studied tyres in the past, but having read a few threads about them I looked up the rating of my Dunlop SP Sport Maxx 050 and it shows 'D' for the fuel economy. What would be the difference between 'A' & 'E' is it minimal or substantial?

Mine are the Maxx 050 which have been discontinued but I am getting in eco mode 50.7 mpg on local runs with them. I hate the road noise so they are coming off the car next week.

beyond the blue · June 9, 2023

1 hour ago, Steven C said:

Mine are the Maxx 050 which have been discontinued but I am getting in eco mode 50.7 mpg on local runs with them. I hate the road noise so they are coming off the car next week.

Can I ask what you are putting on?

Steven C · June 9, 2023

1 hour ago, beyond the blue said:

Can I ask what you are putting on?

Yes after talking with both Michelin & Hankook technical I have decide to go with these. They are for EV's and according to Hankook work well on hybrids as well. Michelin do E-Primacy Acoustic but don't have stock. Really taking a punt and if they don't help then the car will go back. My previous car a BMW was far quieter. Love the ES but not the motorway noise. https://www.hankooktire.com/uk/en/tire/ion/evo.html

beyond the blue · June 9, 2023

1 hour ago, Steven C said:

Yes after talking with both Michelin & Hankook technical I have decide to go with these. They are for EV's and according to Hankook work well on hybrids as well. Michelin do E-Primacy Acoustic but don't have stock. Really taking a punt and if they don't help then the car will go back. My previous car a BMW was far quieter. Love the ES but not the motorway noise. https://www.hankooktire.com/uk/en/tire/ion/evo.html

So the Hankook tyre is rated at 3db less than Maxx 050. On the db scale that equates to a 50% reduction if I've understood it correctly. I hope you come back on here with your findings, good luck with the swap.

NemesisUK · June 9, 2023

50% spl reduction but just ~18% perceived sound reduction.

Test results are one thing but personal experience, another.

Steven C · June 9, 2023

18 minutes ago, beyond the blue said:

So the Hankook tyre is rated at 3db less than Maxx 050. On the db scale that equates to a 50% reduction if I've understood it correctly. I hope you come back on here with your findings, good luck with the swap.

Thanks. Yes I will let you know after Tuesday when they are being fitted. According to Hankook the db levels are for the noise that is generated as a car passes by. A lower level is a good start but it will still depend on how well the ES is insulated in general as to whether this will resolve the issue. I'm hoping that it will make the cabin noise acceptable.

Paul V · June 10, 2023

If it's of interest, I have Dunlop Sport Maxx 050s. Filled the tank with E5 last time and driven 522 miles, mostly motorway and achieved 57.54mpg. My best result yet, after 6 months with the ES300. Just filled the tank with E10, and will see if that makes any difference, as I shall be doing more motorway driving over the next week.

As for road noise, I can't comment as I have nothing to compare it to. However it doesn't seem unduly noisy.

Steven C · June 10, 2023

1 hour ago, Paul V said:

As for road noise, I can't comment as I have nothing to compare it to. However it doesn't seem unduly noisy.

I'm comparing it with the BMW 530e I traded in which was on 17"wheels and my E Class which is also on 17" wheels. Both far quieter on motorway speeds than the ES.

Las Palmas · June 10, 2023

2 hours ago, Paul V said:

As for road noise, I can't comment as I have nothing to compare it to. However it doesn't seem unduly noisy.

The better insulated the car is the less you will see the difference in noise inside the cabin.

A CT is in the lower end with insulation and the difference between 73db and 70db is absolutely not just notable, but increases comfort a lot, music sounds a lot better and it is not needed to play with as much volume as before. In a big limousine road noise is close to not existing anyway, so noise level outside is of little importance.

Some places in the world braking resistance in wet it of far more importance than where I live.

If fuel economy rating means more or less than Colin writes are the new tyres, we got on about a month ago far too early to say anything about. From C to B.

A thing that will in my opinion means a lot more is how handling is better or worse with different tyres and that can only be experienced. Reading about that will tell very little as driving style and condition of car and roads on which we drive will be different from most if not all of us.

Julncamp54 · June 11, 2023

Just a point to ponder inthese warm days …. Tyre pressures … if the pressure is too high it does increase th road noise and overall ride comfort.

with the sunny weather now and a heat wave. I adjusted my tyre pressures to 33 psi @ 15 degC early morning. Which gives the 2.4 bar once the car has gone a short distance which is what is in the handbook.
has made a difference in ride comfort and noise level, currently running at 56.5 mpg E10. Local only

Last trip of 80 miles with 75% motorway bubbling along at 70 (ish) 58.9 mpg ….ac on and 23 deg C outside temp

NemesisUK · June 11, 2023

4 minutes ago, Julncamp54 said:

Which gives the 2.4 bar once the car has gone a short distance which is what is in the handbook.

Handbook recommendations are for cold pressure i.e. before the car has been driven any distance. If you are only reaching the recommended pressure after driving a distance your tyre pressures are below those recommended.

That all said these are only recommended and the difference you measured is easily within accuracy error in the devices used.

Julncamp54 · June 11, 2023

Point taken .. just to clarify. Short distance is when the TPMS registered the pressure reading from start up which is probably less than 500 m.

Also a TPMS reading of 2.4 bar actually could be 2.41 bar or 2.49 bar as display is only Tom 1 decimal place.

therefore measure tyre pressures when cold with a separate accurate tyre pressure gauge .

Dippo · June 11, 2023

25 minutes ago, Julncamp54 said:

Point taken .. just to clarify. Short distance is when the TPMS registered the pressure reading from start up which is probably less than 500 m.

Also a TPMS reading of 2.4 bar actually could be 2.41 bar or 2.49 bar as display is only Tom 1 decimal place.

therefore measure tyre pressures when cold with a separate accurate tyre pressure gauge .

I would hope it was between 2.35 and 2.44 bar.

Las Palmas · June 12, 2023

Just read this today:

What are the tyre ratings for fuel efficiency?

Each tyre can be categorized for its fuel efficiency. Tyres are rated between A – E; A being the most fuel efficient, E bring the least fuel efficient. The difference between each category means a reduction or increase in fuel consumption of 3-4%.

If difference between A and C rating is only 2 - 4% fuel efficiency there is little reason to have this value at all. 6 - 8% would mean something.

Noise from 71 to 69db gave a very notable difference in the CT. Very notable.

Passengers in a big limousine with tons of insulation will probably not even hear the difference.

Steven C · June 14, 2023

On 6/9/2023 at 9:59 PM, beyond the blue said:

I hope you come back on here with your findings, good luck with the swap.

Hi Neil, Have now got the new Hankooks on and yes it has made the cabin / road noise far less. In fact you can now hear the wind noise on motorways whereas before I couldn't. I would say the ride is slightly harder as the tyre walls are stronger for the EV's that use them. What I have noticed is the MPG. I was getting around 53mpg as I ride it around in Eco mode but today on a long run I was getting 64 mpg which seems over the top but the car display said that as did the app. These tyres are supposed to reduce the rolling resistance hence greater MPG. Could be that it's just a hot day but I would say I am pleased I have changed them. Now have four new Dunlops to get rid of.

ColinBarber · June 14, 2023

16 minutes ago, Steven C said:

I would say the ride is slightly harder as the tyre walls are stronger for the EV's that use them.

what is the load index on these new tyres?

beyond the blue · June 14, 2023

19 minutes ago, Steven C said:

Hi Neil, Have now got the new Hankooks on and yes it has made the cabin / road noise far less. In fact you can now hear the wind noise on motorways whereas before I couldn't. I would say the ride is slightly harder as the tyre walls are stronger for the EV's that use them. What I have noticed is the MPG. I was getting around 53mpg as I ride it around in Eco mode but today on a long run I was getting 64 mpg which seems over the top but the car display said that as did the app. These tyres are supposed to reduce the rolling resistance hence greater MPG. Could be that it's just a hot day but I would say I am pleased I have changed them. Now have four new Dunlops to get rid of.

Thanks for getting back. Glad you're happy with them. Can I ask is there a rim protector profile at all?

Steven C · June 14, 2023

4 minutes ago, ColinBarber said:

what is the load index on these new tyres?

Originals were 94Y these are 98W

Steven C · June 14, 2023

8 minutes ago, beyond the blue said:

Thanks for getting back. Glad you're happy with them. Can I ask is there a rim protector profile at all?

Yes but smaller than the Dunlops.

Las Palmas · June 14, 2023

56 minutes ago, Steven C said:

Originals were 94Y these are 98W

Does load index affect ride quality?

The tire load index is not directly correlated to ride quality. While major increases in load index will often mean taller, stiffer sidewalls and higher PSIs, and therefore a stiffer ride, there are many other factors such as suspension, tread, and correct inflation that have more noticeable effects on ride quality.

94 has a load index of 670kg while 98 has 750kg.

How much it changes comfort will be different between different brands.

Most often you get no more than you pay for.

Did you feel any difference?

Steven C · June 14, 2023

1 hour ago, Las Palmas said:

Did you feel any difference?

It's just more noticeable with these tyres that the bumps in the road have a harder feel to them on the same stretches of road. Tyre pressures are the same as previous tyres. The ride on the Dunlops were softer. But at least the cabin is quieter.

beyond the blue · June 15, 2023

12 hours ago, Steven C said:

It's just more noticeable with these tyres that the bumps in the road have a harder feel to them on the same stretches of road. Tyre pressures are the same as previous tyres. The ride on the Dunlops were softer. But at least the cabin is quieter.

Nothing is perfect! There's always a dammed trade off.🤕