Thanks Ken, will look into that when I get back from Geelong.
Joe said
01:42 PM Jan 6, 2012
Happywanderer wrote:
Been to my tyre man. He has pumped tyres up to 40. He said not wise to go up to 45 as when they get hot after driving a while they can go up another 10 which would put them up to 55. Better at 40 going up to 50 when hot he said. He also said the tyres and wheels are the right size.
There is a generally recognised mechanism for ensuring that your tyres are at the right pressure and it is known as "The 4 psi Rule".
Using a good quality pressure gauge, sheck the tyre's pressure when it is cold. Then drive for at least 30 minutes and re-check the pressure. The tyre pressure should have gone up by 4 psi. If it has gone up by more then the tyre has been getting too hot and the starting pressure was too low. If it doesn't increase by the 4psi then the starting pressure was too high.
Obviously, the pressures you need for travelling around town and being fully loaded and travelling at speed on the highway will be different so it is a matter of working this out for each different type of driving you do.
The only variable to this rule is for Light Truck tyres where an increase of up to 6psi is acceptable as their heavier construction will generate, or at least tolerate, more heat.
My brother had a van similar to Myrtle, it was a Ford Econovan, and he ended up running his at 34psi around town and changing that to be 40psi in the front tyres and 42psi in the rear tyres for his loaded up runs down the freeway. You might consider using those pressures as starting points for your tests if you choose to bother.
I do get rather "anal" about tyre pressures though and I have a compressor mounted under the driver's seat (with a long hose) to allow me to re-inflate tyres whenever I drop the pressures, and I do drop them for different road surfaces all the time.
For instance, I will normally drop them to 22psi if I am driving on sand, or 18psi if I am towing the van down the beach, and I have gone as low as 12psi for really soft sand.
Similarly, I will drop them down to 26psi if I am driving down a gravel road littered with gibbers. It is important to reduce speed as well of course, to keep the heat build up as low as possible.
Enjoy the drive to Geelong - I used to live there and I still have some very fond memories of the place.
Happywanderer said
11:43 AM Jan 9, 2012
Hows this for a big difference in fuel economy.
On Saturday I travelled down from Echuca to Geelong. I had a full tank when I left. I then filled up in Daylesford.
A total of 198 ks..... I filled up, it took 23.38 litres.
Using the online calculator that works out to 11.81 litres per 100 ks.
or 8.47 ks to the litre.
How can that be so different to the firast calculation and so much better.
Happywanderer said
11:47 AM Jan 9, 2012
The previous estimation was 16.78 litres per 100 ks
or 5.96 ks per litre
Easier than going looking back a page for the figures.
-- Edited by Happywanderer on Monday 9th of January 2012 11:49:32 AM
Gerty Dancer said
01:45 PM Jan 9, 2012
Glad to hear this Marj. You must be feeling better. All such calculations need to be done over long distances, and even better over several fuel-tank fills.
Boroma577 said
06:31 PM Jan 9, 2012
Happywanderer wrote:
How can that be so different to the firast calculation and so much better.
Just a couple of things come to mind HW..
Difference in terrain, difference in weather conditions, winds, tyres pumped up more and your driving style.....you were consciously making and effort to drive more efficiently......makes a lot of difference.
Was Myrtle as heavily laden with water, camp gear, food clothes etc??
Happywanderer said
08:12 PM Jan 9, 2012
Could be the reaaon Boroma. All of those. I didn't bother filling the water tank as staying at my sisters. There would be some in it but nowhere near full. Tyres pumped up to 40. The load would be similiar to last trip, may have slight difference in weight. Actually a bit more as I brought down my sewing machine for sister to play around with. I did go the same way for the first 50ks as prefer the country roads. Then it was 90 all the way except through the towns.
Boroma577 said
08:29 PM Jan 9, 2012
Happywanderer wrote:
Could be the reaaon Boroma. All of those. I didn't bother filling the water tank as staying at my sisters.
The load would be similiar to last trip, may have slight difference in weight. Actually a bit more as I brought down my sewing machine for sister to play around with.
I did go the same way for the first 50ks as prefer the country roads. Then it was 90 all the way except through the towns.
You did not have water in the tanks but you did take the sewing machine.....how do they compare?? Remember for every litre of water you have it is a kilo in weight.....20 litres water = 20 kilos weight.
Did you still have your outside furniture packed in Myrtle??
And you may well have traveled the same route but weather conditions also contribute to fuel usage....hot, cold, winds etc
Slowing down, braking and then having to build speed again are all considerations too as is traffic....more this time less next time etc.
Ron and Shirley said
08:40 PM Jan 9, 2012
HW
Agree with Boroma and on Saturday there was a strong Northerly wind in Melbourne so you would have had a tailwind.
Just collect your data, then average it out over a number of trips.
Don't panic about it, you will get Highs and Lows
BTW, Echuca to Geelong, thats got to be downhill
GaryKelly said
04:54 AM Mar 3, 2013
Very interesting thread this one. I've learned quite a bit from reading the whole 3 pages. For one thing, petrol is cheaper than a motel. The log book for fuel/mileage is a good idea. As someone said, it's not so much about how many liters per 100 kilometers you're using but knowing the distance your vehicle can travel between fills.
patrolst said
10:25 AM Mar 3, 2013
If the Speedo/Odometer are not working the speed and distance can be obtained from a GPS if Marg has one.
-- Edited by patrolst on Sunday 3rd of March 2013 10:26:51 AM
barina said
01:50 PM Jan 3, 2014
I have just worked my fuel consumption over my first couple of short trips and I got 11.88lts per 100kms and 8.42kms per ltr. In a 1998 Mercedes Sprinter, manual, deisel turbo. I guess it sounds ok by what I have read?
There is a generally recognised mechanism for ensuring that your tyres are at the right pressure and it is known as "The 4 psi Rule".
Using a good quality pressure gauge, sheck the tyre's pressure when it is cold. Then drive for at least 30 minutes and re-check the pressure. The tyre pressure should have gone up by 4 psi. If it has gone up by more then the tyre has been getting too hot and the starting pressure was too low. If it doesn't increase by the 4psi then the starting pressure was too high.
Obviously, the pressures you need for travelling around town and being fully loaded and travelling at speed on the highway will be different so it is a matter of working this out for each different type of driving you do.
The only variable to this rule is for Light Truck tyres where an increase of up to 6psi is acceptable as their heavier construction will generate, or at least tolerate, more heat.
My brother had a van similar to Myrtle, it was a Ford Econovan, and he ended up running his at 34psi around town and changing that to be 40psi in the front tyres and 42psi in the rear tyres for his loaded up runs down the freeway. You might consider using those pressures as starting points for your tests if you choose to bother.
I do get rather "anal" about tyre pressures though and I have a compressor mounted under the driver's seat (with a long hose) to allow me to re-inflate tyres whenever I drop the pressures, and I do drop them for different road surfaces all the time.
For instance, I will normally drop them to 22psi if I am driving on sand, or 18psi if I am towing the van down the beach, and I have gone as low as 12psi for really soft sand.
Similarly, I will drop them down to 26psi if I am driving down a gravel road littered with gibbers. It is important to reduce speed as well of course, to keep the heat build up as low as possible.
Enjoy the drive to Geelong - I used to live there and I still have some very fond memories of the place.
On Saturday I travelled down from Echuca to Geelong. I had a full tank when I left. I then filled up in Daylesford.
A total of 198 ks..... I filled up, it took 23.38 litres.
Using the online calculator that works out to 11.81 litres per 100 ks.
or 8.47 ks to the litre.
How can that be so different to the firast calculation and so much better.
The previous estimation was 16.78 litres per 100 ks
or 5.96 ks per litre
Easier than going looking back a page for the figures.
-- Edited by Happywanderer on Monday 9th of January 2012 11:49:32 AM
All such calculations need to be done over long distances, and even better over several fuel-tank fills.
Just a couple of things come to mind HW..
Difference in terrain, difference in weather conditions, winds, tyres pumped up more and your driving style.....you were consciously making and effort to drive more efficiently......makes a lot of difference.
Was Myrtle as heavily laden with water, camp gear, food clothes etc??
Tyres pumped up to 40.
The load would be similiar to last trip, may have slight difference in weight. Actually a bit more as I brought down my sewing machine for sister to play around with.
I did go the same way for the first 50ks as prefer the country roads. Then it was 90 all the way except through the towns.
You did not have water in the tanks but you did take the sewing machine.....how do they compare?? Remember for every litre of water you have it is a kilo in weight.....20 litres water = 20 kilos weight.
Did you still have your outside furniture packed in Myrtle??
And you may well have traveled the same route but weather conditions also contribute to fuel usage....hot, cold, winds etc
Slowing down, braking and then having to build speed again are all considerations too as is traffic....more this time less next time etc.
HW
Agree with Boroma and on Saturday there was a strong Northerly wind in Melbourne so you would have had a tailwind.
Just collect your data, then average it out over a number of trips.
Don't panic about it, you will get Highs and Lows
BTW, Echuca to Geelong, thats got to be downhill
If the Speedo/Odometer are not working the speed and distance can be obtained from a GPS if Marg has one.
-- Edited by patrolst on Sunday 3rd of March 2013 10:26:51 AM
I have just worked my fuel consumption over my first couple of short trips and I got 11.88lts per 100kms and 8.42kms per ltr. In a 1998 Mercedes Sprinter, manual, deisel turbo. I guess it sounds ok by what I have read?