2010 Auris MPG has suddenly nosedived

[Beekeeper D]

16 hours ago, FROSTYBALLS said:

Where one is renewing just two tyres, for a number of years, industry best practice has been to fit new tyres onto the rear axle, and to move the part worn rear tyres to the front - this is regardless of whether a car is either front or rear wheel drive.

True. 

But this is based on the assumption that it is better to understeer (run wider than steered) than to ever risk 'hanging the tail out'. This in turn is because, in a worrying understeer situation, the ordinary driver is most likely to instantly lift off the throttle (and turn in more), which will reduce the understeer as the speed scrubs off - and this is held to be safest. 

My personal preference is to have the best grip possible at the front, for braking, aquaplaning, steering and even accelerating in a fwd car. I think that having the strongest braking available is a safer choice than having a terminal understeer characteristic. But that's my conscious and considered choice. For me, with my driving experience and preferences. Not a general recommendation.

 

 

Personally, I'd expect that changing high rolling resistance tyres to the rear (of a fwd car) would give better mpg than having them at the front, because at the rear they would be carrying less weight (at least until the car is heavily loaded).   

[Heidfirst]

Having had a fwd car (4th gen Mazda 323) where it was quite easy to invoke lift-off oversteer (quite fun to play with) I also prefer to put new tyres on the front of my Avensis. With the heavy 2.2 up front it understeers like a pig anyway. 

However, it's also my personal choice done with the experience of over a million miles of driving (incl. some motorsport) & the fact that I tend to change my tyres at ~3mm rather than the legally mandated 1.6mm.

[gazzaman28]

OK here's a possibility... The first picture is the front left tyre, the second is the front right, yet the tread pattern is the same on both, they both curve towards the left. I can't see any rotation arrows on the tyres but I'm convinced one of them is the wrong way round. I'm sure that's not gonna help the economy.

[FROSTYBALLS]

If you check the Kumho website for the exact tyre you have, that should tell you whether they are directional or not.

[gazzaman28]

4 hours ago, FROSTYBALLS said:

If you check the Kumho website for the exact tyre you have, that should tell you whether they are directional or not.

I've tried the UK and US sites, they are utterly useless at giving any sort of detailed specs of their tyres. The only thing I've found is on my web order form from BlackCircles.com which states that these tyres are asymmetrical, which I believe means they should have an inside and an outside marking on them, although I can't find this anywhere on the tyres themselves.

[unclepoo]

Asymmetric tyres have an outside edge with thicker blocks and more tread towards the inside wall for better water clearing. It`s not a rotational thing.

[Cyker]

I think that's normal; The newer Uniroyal RainExperts also have that, where it looks like the grooves are pointing the wrong way when you put them on the other side, but apparently this is by design...

 

 

[Smiling Taxi]

Rather than look at the tyres, have you checked that the fan for cooling the hybrid batteries has a clear filter in front of it? . Even though I hoover my mats/carpet  etc. 2/3 every week, mine was so clogged after 14 months, you could not see thru the filter, and had to be replaced. MPG went up from 42 to 63, lot happier!!

[gazzaman28]

15 hours ago, Smiling Taxi said:

Rather than look at the tyres, have you checked that the fan for cooling the hybrid batteries has a clear filter in front of it? . Even though I hoover my mats/carpet  etc. 2/3 every week, mine was so clogged after 14 months, you could not see thru the filter, and had to be replaced. MPG went up from 42 to 63, lot happier!!

I wasn't even aware of the fan or the filter. Is this something I can check myself? If so where is it? Somewhere in the boot I guess...

[gazzaman28]

An update on the tyres/wheels situation. I've just had another tyre replaced (the Bridgstone which was just about legal), I swapped it with a Michelin Primacy 3 and got the garage to stick that and the Goodyear (still 5-6mm) on the front and the Kumhos on the back. I also asked them to check how well the wheels spin in neutral and they said the front driver's side did have some rub, so it's going back to Toyota Helensburgh on Thursday to get that checked out. I will ask about the oil at the same time.

We'll get this sorted in the end, thanks all for your helpful suggestions so far :)

[Smiling Taxi]

Batteries are under rear seats, the fan/filter, at least on mine are behind a plastic grill on n/s just under corner of rear seats. Not sure if you can readily remove this outer piece of trim, but mine was removed in seconds by Mr T.  Good luck, and as you say, we'll get there!!

 

[gazzaman28]

Hopefully good news update...

My wife took the car into the Toyota dealer this morning, they confirmed that one of the brake callipers was rubbing. This has now been fixed, she reset the average MPG and it appears to be much better already, 57MPG on first run. Fingers crossed this has solved everything.

Thanks @unclepoo for your suggestion and to everyone else for hints and tips too.

[Anthony Poli]

42 minutes ago, gazzaman28 said:

Hopefully good news update...

My wife took the car into the Toyota dealer this morning, they confirmed that one of the brake callipers was rubbing. This has now been fixed, she reset the average MPG and it appears to be much better already, 57MPG on first run. Fingers crossed this has solved everything.

Thanks @unclepoo for your suggestion and to everyone else for hints and tips too.

I have had the same problem with a previous car, after bumping the kerb while driving on snow and ice. The wheel ended up getting hot.