Poor Fuel Economy With New Tyres

[Grumpy Cabbie]

Just fitted some new Bridgestone ER300 Ecopias to my car (which are the correct tyres) and found that my tank average has dropped to 45 mpg! This is one of the lowest I've ever had. I do know from past experience that this will increase back to normal once the tyres are bedded in.

So quick bit of advice. The mpg's will take a hit when you put new tyres on BUT make sure you get the correct low rolling resistance tyres, such as Bridgestone Ecopia's, otherwise the mileage hit will never recover.

[dwilson]

Just fitted some new Bridgestone ER300 Ecopias to my car (which are the correct tyres) and found that my tank average has dropped to 45 mpg! This is one of the lowest I've ever had. I do know from past experience that this will increase back to normal once the tyres are bedded in.

So quick bit of advice. The mpg's will take a hit when you put new tyres on BUT make sure you get the correct low rolling resistance tyres, such as Bridgestone Ecopia's, otherwise the mileage hit will never recover.

Was this your first set? About 33k miles?

If so that is very good!

[Grumpy Cabbie]

Oh I wish it was! This is my second set of tyres. The first lot were replaced at 14k miles and these at 33k miles. To be honest, I'd be lucky to get more than 16k out of a set of front tyres in my job due to all the turning, starts stops, roundabouts etc.

[Chris Dance]

On the Gen3 Prius do you have to do a tyre reset after tyre change like you have to on the Gen 2 Prius?

[fuel miser]

On the Gen3 Prius do you have to do a tyre reset after tyre change like you have to on the Gen 2 Prius?

That's only on the T-Spirit gen 2, my T4 doesn't have it. Out of interest, what does it actually do?

[ian rooke]

Hi the re-calibration is used to make the Sat Nav more accurate when it is in a tunnel where it cannot receive a signal it will still know where you are.

[fuel miser]

Hi the re-calibration is used to make the Sat Nav more accurate when it is in a tunnel where it cannot receive a signal it will still know where you are.

That would explain why T3/T4 doesn't have it (no sat-nav). So presumably it must recalculate the circumference of the tyres (front only?). Does it also continue to adjust during the life of the tyres?

(I assume it must or it wouldn't need to be reset!)

[Seamaster73]

Hi the re-calibration is used to make the Sat Nav more accurate when it is in a tunnel where it cannot receive a signal it will still know where you are.

Really? On my current car the reset is simply to ensure the tyre pressure warning indicator is accurate.

[Doesn'tExist]

Just fitted some new Bridgestone ER300 Ecopias to my car (which are the correct tyres) and found that my tank average has dropped to 45 mpg! This is one of the lowest I've ever had. I do know from past experience that this will increase back to normal once the tyres are bedded in.

So quick bit of advice. The mpg's will take a hit when you put new tyres on BUT make sure you get the correct low rolling resistance tyres, such as Bridgestone Ecopia's, otherwise the mileage hit will never recover.

OEM Tyres are now Michelin Premacy HP, not even low rolling resistance tyres. That seems pretty bad what you get. I'd change the tyres again ;-)

[Dave R.]

Just fitted some new Bridgestone ER300 Ecopias to my car (which are the correct tyres) and found that my tank average has dropped to 45 mpg! This is one of the lowest I've ever had. I do know from past experience that this will increase back to normal once the tyres are bedded in.

So quick bit of advice. The mpg's will take a hit when you put new tyres on BUT make sure you get the correct low rolling resistance tyres, such as Bridgestone Ecopia's, otherwise the mileage hit will never recover.

OEM Tyres are now Michelin Premacy HP, not even low rolling resistance tyres. That seems pretty bad what you get. I'd change the tyres again ;-)

Currently gutted by increased fuel consumption, and confused over tyres....

To explain...

Last week had the Gen III T-Spirit serviced (30,000 miles) & was told I needed 3 new tyres (2 front worn, 1 rear damaged). It's a lease car, so I didn't really get any say over type of tyre. Went to KwikFit - they had just 3 tyres of the right size in stock.... 2 x Bridgestone Potenza REO50, 1 x Continental Contisport Contact 3.

Since then, fuel consumption is through the roof. I've just done a 400 mile return trip cruising down the motorway at speeds between 55 & 70, some on cruise control but generally not thrashing it - last time I did the journey, I averaged between 57-59mpg (by Fuelly reconing!); this time it was 49mpg.

The original tyres on the car were Michelin Primacy HP (which I now find are NOT low-resistance "Eco" tyres...so much for that theory!).

Pressures are by the book.

Now, I DO have an issue following the serivce of the "wrong oil" in the engine - but it turns out they've been putting the wrong oil in the car since its first service... perhaps this explains why my MPG over the life of the car has been in the mid to low 50's! After conversations with Toyota customer service, I'm still waiting for the service manager to get back to arrange for the oil to be replaced with 0W20.... So, all considered, it looks like the tyres have just added 10-15% to my fuel consumption! I just hope that, as GrumpyCabbie says, they will bed in & I'll get something approaching reasonable consumption again! I suppose the only other thing to try will be to slightly over-inflate the tyres (but I don't like the sound of this on the grounds of a)safety, b)ride and c)road noise)

[Grumpy Cabbie]

It might also be the sudden change in weather we've had too. The problem with my tyres has been resolved so I now have 4 x Turanza ER300 Ecopias all round - 2 new on the front, yet my fuel economy has been dropping lately and the journeys I could have got 60 + mpg are now more like 54 mpg etc.

I still think the tyres need a little time to bed in but the colder weather is coming in to play also - the engine has to work more to keep itself and the cabin warm and the HV Battery isn't quite as efficient either. I've had to scrape ice from my windscreen twice in 3 days this week and today when I dropped someone off in the sticks the temp guage was showing -1c!!!

So it could be the end of the summer high mpg period

[Dave R.]

It might also be the sudden change in weather we've had too. The problem with my tyres has been resolved so I now have 4 x Turanza ER300 Ecopias all round - 2 new on the front, yet my fuel economy has been dropping lately and the journeys I could have got 60 + mpg are now more like 54 mpg etc.

I still think the tyres need a little time to bed in but the colder weather is coming in to play also - the engine has to work more to keep itself and the cabin warm and the HV battery isn't quite as efficient either. I've had to scrape ice from my windscreen twice in 3 days this week and today when I dropped someone off in the sticks the temp guage was showing -1c!!!

So it could be the end of the summer high mpg period

Well, the oil was changed to 0W20 (allegedly) and I've had a couple of tanks of petrol following the change... and fuelly shows my consumption solidly at around 48mpg compared with 58-60mpg before the tyres were changed. The oil change (from 5W30 up to 0W20) seems to have made very little difference to consumption. I realise the weather is getting colder, but not THAT much - I was getting 49mpg or so last January when the temperatures were consistently sub-zero. What is also quite depressing is that I've a T-Spirit with 17 inch wheels - looking at what KwikFit have on offer, it doesn't appear that there are any particularly low rolling resistance tyres on their books to fit :( (must explain, lease car so I'm stuck with going to KF for the tyres... & they get picky about brands... something to do with their discounts I guess!). I'll know the damage for sure when I get Fuelly's average over the next month.

[ian rooke]

Hi over the last three weeks my petrol consumption has dropped 9 mpg as nothing has been done to the car I put it down to using the heater more and the headlights longer as well as colder weather, it has just started improving this week where it has got slightly warmer.

[Jan&tone]

Hi over the last three weeks my petrol consumption has dropped 9 mpg as nothing has been done to the car I put it down to using the heater more and the headlights longer as well as colder weather, it has just started improving this week where it has got slightly warmer.

Hi Ian, you are correct. Prius, and I'm assuming the HSD Auris suffer from the cold weather, or at least the consumption does. I noticed it a fair bit in my gen2, and I'm wondering if the drop-off will be the same in the slightly larger engined gen3....

[ashpole]

Hi over the last three weeks my petrol consumption has dropped 9 mpg as nothing has been done to the car I put it down to using the heater more and the headlights longer as well as colder weather, it has just started improving this week where it has got slightly warmer.

Hi Ian, you are correct. Prius, and I'm assuming the HSD Auris suffer from the cold weather, or at least the consumption does. I noticed it a fair bit in my gen2, and I'm wondering if the drop-off will be the same in the slightly larger engined gen3....

I had a noticeable increase in fuel consumption on some recent trips, I've narrowed it down to when it's been raining. I tried turning off the obvious like heater, wipers (difficult!) and headlamps but that didn't improve things much. I'm leaning towards the performance of the Michelin Primacy HPs in the wet - not sure if that is good or bad news, perhaps they shift so much water their equivalent rolling resistance increases dramatically.

[johalareewi]

I had a noticeable increase in fuel consumption on some recent trips, I've narrowed it down to when it's been raining.

You will do. Rain puts more drag on the car than air so the engine has to work more to keep moving through it.

[agfs]

Having had 2 new Ecopiias fitted on the front at 35k + and then started off with mpg at 42.7 for a while, after some 60 miles it had risen to 64.2 mpg so I am convinced that Ecopias are good bargains and the need to maintain correct tyre pressures ( as many have mentioned before) is essential in maintaining good mpg figures.

[Sagitar]

I have just put winter tyres back on, with 15 inch wheels, so I wait with interest to see what happens to the mileage.

[Ancient Nerd]

I have just put winter tyres back on, with 15 inch wheels, so I wait with interest to see what happens to the mileage.

I would expect it to:

• improve slightly due to the smaller wheels (the T3 figures are better than the T4 and TS, I think solely due to the difference in wheel and tyre).
  
• worsen a bit, because winter tyres are (probably) not low rolling resistance.
  
• get a lot worse, because the weather is getting colder. But that would happen anyway.
  

Whatever happens, I am very interested to hear what happens. Keep us posted.