Fuel Economy

[EVN-88G]

I run about 40psi in my tyres.... apparently lotsa people only runnin 30-ish?

Yer 40Psi is pretty high, in my golf i run about 32-33 in the front and 30 in the back aswell. Even in my old car (toyota 4runner) with MASSIVE 33' x 12.5' Mickey T Baja Mud Claws i only ran about 34-35Psi!!

[brad]

What alignment specs have they set the car at (both ends)?
What tyre pressures are you running?
What is the difference in weight between the Bridgestone & the OEM tyre?
How do you know they are the same rolling resistance?

Hi,

I recently got some new tyres put on Bridgestone Adrenalin RE001's in 225/50 R16's on OEM Rims.

Now, I am having some alignment problems which, I am hoping to get sorted tomorrow by Traction tyres in rowville who come highly recommended, but ever since I changed to these tyres, my fuel economy has jumped about two or three litres !

Is this because I went from 205/55 R16's to the wider tyre with the SAME ROLLING RESISTANCE or is it possible the alignment is creating drag ?

Because it's going to cost a lot to have my fuel economy suffer so much !

[qsilverza]

Hmmm,

Here we go,


Rear Axle...

Camber - L 1.40 and -1.27

Toe 1.9 and 1.9

total 3.8

Front Axle

Castor 0.00 and 0.00

Camber L - 0.26 and - 0.22

Toe -0.1 and -0.1





Tyre pressures are 34 front and 32 rear

Don't know the difference.

Because, I checked it up and every tyre store I rang around checked and said there is virtually no difference in the rolling diameter.

In any case, I took the tyres backed and they swapped them over for 205/55's so I will drive it for a day or two and see how we go. I was quite happy with the service, as the tyres already had 300 Km's on them and they were willing to swap.

What alignment specs have they set the car at (both ends)?
What tyre pressures are you running?
What is the difference in weight between the Bridgestone & the OEM tyre?
How do you know they are the same rolling resistance?

[Mrk_Mickey]

Sounds good mate, your tyre guys sound like good blokes Hope it goes well for you.

[No457 Snowy]

In any case, I took the tyres backed and they swapped them over for 205/55's so I will drive it for a day or two and see how we go. I was quite happy with the service, as the tyres already had 300 Km's on them and they were willing to swap.

That's great mate, that they would swap em over for you, and your pressures sound spot on. Here's hoping the swap gets it all sorted for you, you'll be better off with that size anyway, as it's the optimum for the rim.

Good luck.

Snowy.

[brad]

Hmmm,

Here we go,


Rear Axle...

Camber - L 1.40 and -1.27

Toe 1.9 and 1.9

total 3.8

Front Axle

Castor 0.00 and 0.00

Camber L - 0.26 and - 0.22

Toe -0.1 and -0.1

Tyre pressures are 34 front and 32 rear

AAAhh! before you said rolling resistance which is very different from rolling diameter. I was wondering where you got resistance values from.

There's nothing in your alignment figures that would cause excessive fuel consumption.

The Castor figures look odd though. I would have thought most modern cars would be running at least 3degrees +ve castor. It makes no difference to tyre wear or economy though.

Front camber looks a fraction conservative - If the adjustment was available I would run more like -0.5 to -1 but if your tyre wear is even then -0.25 is right for your driving style.

Is that toe-out on the rear? 3.8mm(?) total toe-in seems an awful lot.

Tyre pressures might go up a fraction but it depends on sidewall flex & how you drive.

[qsilverza]

Hi, yeh they were quite good sports about changing them. Very happy about that, though I think he should have steered me away from them in the first when I asked what he thought.

My bad, Yep Rolling diameter

Still getting slight vibration at speed but otherwise it seems to be a hell of a lot better in nearly every aspect though I haven't pushed hard yet.

Maybe the vibration is from one of the wheels...

AAAhh! before you said rolling resistance which is very different from rolling diameter. I was wondering where you got resistance values from.

There's nothing in your alignment figures that would cause excessive fuel consumption.

The Castor figures look odd though. I would have thought most modern cars would be running at least 3degrees +ve castor. It makes no difference to tyre wear or economy though.

Front camber looks a fraction conservative - If the adjustment was available I would run more like -0.5 to -1 but if your tyre wear is even then -0.25 is right for your driving style.

Is that toe-out on the rear? 3.8mm(?) total toe-in seems an awful lot.

Tyre pressures might go up a fraction but it depends on sidewall flex & how you drive.

[spritle]

weird to have that.

any issues with the consumption?



I went from the Dunlop SP200E 175/80 14's (stock 1.6) to Yoko A509 215/65 14's and didn't have any issues (other than it gripped better).

It's currently sitting on Yoko C drive 215/60 15's. More steering vibration than when it was new but then it's got 110K kms and poly bushes on the front wishbones.


I've heard of others putting 225/50 16's on stock rims but didn't hear about them having issues.