MPG west to east / east to west ???

[so called]

So I drove to Germany in my MB CLS 320 CDI and got exactly 42mpg.
Drove carefully but pushed on so very pleased with the result.

Two weeks ago I drove back to the UK and got 38,5mpg.
Same attitude, even more careful with my right foot when I realised it was becoming a challenge to reach the 40 mark.
I decided it was due to having had winter tyres fitted four days earlier.

Fast forward to last Wednesday and drove back to Germany again with my BH and again, easily reached 42mpg.

Is it down hill to Germany or have I generally got the wind behind me or is it my MB wanting to 'go home'?

[thatdude]

I just had a look at a globe, and it is indeed downhill to germany. You could probably stick it in a high gear and coast there if you wanted?

[Spare tyre]

wonder if wind direction and temp would make a difference?

[JordanTurbo]

thatdude said:

I just had a look at a globe, and it is indeed downhill to germany. You could probably stick it in a high gear and coast there if you wanted?

This.

Looking at my globe, I wouldn't suggest going any further south than the equator without sticky tyres as you'll fall straight off all together.

Edited by JordanTurbo on Friday 13th December 09:44

[HertsBiker]

Interesting ideas. I seem to have a faster journey west to east, almost every trip car or bike!

[MX7]

When you came back you had the rotation of the earth to contend with.

[CBR JGWRR]

MX7 said:

When you came back you had the rotation of the earth to contend with.

Irrelevant - same distance covered as far as the car cares.

[MX7]

You're not.... no you can't be...

[sawman]

Its probably a wind issue - european prevailing wind is probably west to east, so on your way back the "airspeed" of the car may be higher than the opposite way, making the engine work harder to achieve the same roadspeed.

I drove my jeep north from Minneapolis a few years ago and was surprised at how little gas I needed to add at grand forks to get back home, the chap at the next pump was similarly surprised when refilling his discovery, there was a strong south wind blowing that day. The jeep averaged over 30mpg on that trip (not bad for a 4.0 XJ cherokee)

[Monkeylegend]

It could be the tyres.

My mpg dropped about 4 mpg and then gradually came back up when I put new winters on last year and this. They seem to take about 500 miles or so of motorway running to bed in.

It could also be due to continental drift.

[Joey Ramone]

MX7 said:

You're not.... no you can't be...

I think he is...

[Zwolf]

Monkeylegend said:

It could also be due to continental drift.

[sploosh]

Nothing to do with going uphill / downhill - fact.

Its about magnetism. Obviously you car has a negative polarity and you're trying to go north ... towards the north pole, which is also "negative" (hence the phrase "grim up north".

If you pop into Halfords you can get a polarity reversal flange.

hope that helps.

[Toltec]

MX7 said:

You're not.... no you can't be...

He is right, it is irrelevant in comparison to the Earths orbital velocity.

[ging84]

how far into Germany are you getting on the fuel you bought in UK

if you are leaving this country with a full tank and then having to fill up over there one or more times i would not be surprised if there is a difference in fuel

[davepoth]

CBR JGWRR said:

MX7 said:

When you came back you had the rotation of the earth to contend with.

Irrelevant - same distance covered as far as the car cares.

It's almost as if the car was on some kind of conveyor belt.

[Monkeylegend]

Toltec said:

MX7 said:

You're not.... no you can't be...

He is right, it is irrelevant in comparison to the Earths orbital velocity.

But what about the earths tilt and rotational velocity, didn't think of that did you hah.

[Mr2Mike]

Monkeylegend said:

It could also be due to continental drift.

Best to fit Pirelli or Mitchelin then?

[djglover]

Wind for sure. Used to drive to Cardiff a lot and returning to London with the prevailing wind saw up to 10% better mpg

[blasos]

Monkeylegend said:

Toltec said:

MX7 said:

You're not.... no you can't be...

He is right, it is irrelevant in comparison to the Earths orbital velocity.

But what about the earths tilt and rotational velocity, didn't think of that did you hah.

Orbital velocity and rotational velocity are different concepts. Earth orbits the Sun, it rotates (with a wobble) about its own axis. He was joking about the rotational velocity, not the orbital velocity.

The tilt is in relation to the ecliptic, the apparent path of the Sun around the Earth (this is apparent, although false the geocentric model is useful for astronomy). There is no up or down in space, hence the tilt is not not relevant here (even if you weren't joking).

In the case of your assertion being taken seriously. Rotational velocity isn't a factor. Galileo's Ship explains this.
http://en.wikipedia.org/wiki/Galileo's_ship