MPG improvement winter to summer tyre swap

[snoop51]

I currently travel the same route every Monday morning before traffic builds so can achieve reasonably close results. I changed my wheel / tyre combination from winter 17" to the fitted as standard 18" summer conti's over the weekend. I have then driven down the A12 over the Dartford crossing down the A2/M2 to Whitstable average speed of 66MPH. I did the same last week with my winters on and managed at best 41.1MPG , this morning I achieved 45.1MPG:bannana: . Just waiting for the warmer weather now as I did achieve over 46MPG last year so now the engine is a bit looser, 15000 miles now hopefully it'll manage even more.

 

[grober]

Blow up your tyres by 5 psi and you will probably achieve that and more . The car ride will suffer and the tyres will wear unevenly but everything has its price? MB have just recommended that to all W212 E class 220CDi owners who have been complaining they can't achieve the published fuel consumption figures.

 

[snoop51]

Blow up your tyres by 5 psi and you will probably achieve that and more . The car ride will suffer and the tyres will wear unevenly but everything has its price? MB have just recommended that to all W212 E class 220CDi owners who have been complaining they can't achieve the published fuel consumption figures.

The car ride is already more fidgety over bumps than with the 17" winters on, plus what the point of having recommended tyre pressures then telling you to ignore them I'm not particularly bothered about reaching the "Nivarna" of manufacturers figures. I just like to see how much I can get on a correctly set up vehicle by driving at a good time of day, looking ahead to plan for not using the brakes etc., I reckon come the summer I could see between 48 - 50MPG which I'd be well chuffed with in a W212 350CDI.

I used to have a 2.0TDCI Mondeo which I normally ran at around 54 - 56MPG so if I can achieve the figure I think I can out of this I'll be more comfortable and a happy bunny.

I just found it interesting how changing from winter compound tyres to summer compounds affected the MPG. I knew it would make a difference but wasn't thinking 4MPG without really trying. I also thought it might be of interest to members on here who run on winter compound all year round especially with fuel rocketing as it has over the past 12 months.

 

[dtldesign]

using some rough figures and an average of 12000 pa that could be a saving of just over £200 a year...
mmm quite interesting... trying to stay clear of the winter tyre debate.....

 

[Charles Morgan]

Swapped over my own, no great difference in mpg, but I do know that when swapping over, I ensured all the tyres were at the correct pressure having put them on, something I suspect has a role. As has a noticeable improvement in temperature, at which point winter tyres are not optimal.

 

[snoop51]

Swapped over my own, no great difference in mpg, but I do know that when swapping over, I ensured all the tyres were at the correct pressure having put them on, something I suspect has a role. As has a noticeable improvement in temperature, at which point winter tyres are not optimal.

All tyres checked on a weekly basis and on changeover so all at recommended pressures. The temperature this morning when I set off was 7 deg C so at the low end for summer tyres, high end for winters. However I've never managed any more than 42.5MPG on the same run with the winters fitted all through the winter. The winter tyres are Dunlop Winter Sport, the summers standard fit Conti 3's so perhaps it's more a manufacturer thing rather than the winter / summer issue

 

[grober]

Colder ambient temperatures would presumably mean the engine will take slightly longer to warm up and powertrain losses due to increased viscosity of lubricants [ engine/gearbox/differential] will be slightly greater, meaning the mixture enrichment+ increased idle speed + greater alternator load to recharge battery starting drain[=more fuel]will last slightly longer than in warm conditions. This would be less noticeable on a longer journey but still possibly significant if considering small changes in fuel consumption.

 

[snoop51]

Colder ambient temperatures would presumably mean the engine will take slightly longer to warm up and powertrain losses due to increased viscosity of lubricants [ engine/gearbox/differential] will be slightly greater, meaning the mixture enrichment+ increased idle speed + greater alternator load to recharge battery starting drain[=more fuel]will last slightly longer than in warm conditions. This would be less noticeable on a longer journey but still possibly significant if considering small changes in fuel consumption.

Sorry but reset computer at the entry to the A12 which is 12 miles from home so engine etc. up to temperature on all occasions.

 

[dibblodocus]

I swapped my Pirelli Sottozeros (winter) back to the Michelin Energy tyres that were supplied with my W204 C220CDI in December this weekend (both the same size - 205/55 R16). I managed 44MPG on a fast run without thinking about economy - more overtaking a lorry to get to work on time!

Although not even remotely a scientific test, my gut feel is that the Michelin Energy tyres are quieter than the Sottozeros but also appear to have less rolling resistance and hence use less fuel.

I have to say that the Pirelli Sottozeros were awesome this winter and I would not have wanted to be without them. I live in Scotland and the snow was on the ground for weeks. Never once did I come close to getting stuck. The security they provide in the snow really is quite amazing. They cost £400 for a set but then again the Michelins have been sat in the garage unused. Recommended.

 

[st13phil]

All the major tyre manufacturers have for a number of years been putting a great deal of R&D effort into reducing rolling resistance and therefore improving fuel economy. I doubt that the technology that helps them achieve that would be applicable to winter tyres as by their nature they need to be much more flexible so that they grip well in lower temperatures. That flexibility absorbs energy and so costs in terms of fuel consumption, so it's not entirely surprising that you see such a change in consumption twixt winter and summer tyres.

A good heads up though for anyone who continues to use winter tyres once the weather warms up.

 

[Dieselman]

Snoop.
What you need are some steel train wheels as they give great economy due to very low rolling resistance. The first journey will be a bit precarious, but after that you can just set the cruise and sit in the back.

 

[snoop51]

Snoop.
What you need are some steel train wheels as they give great economy due to very low rolling resistance. The first journey will be a bit precarious, but after that you can just set the cruise and sit in the back.

LOL Perhaps I can attach some other vehicles to the back, share the costs, maybe rename it hmmmmm MB train perhaps. What about the ride?? Do you think it will be greatly affected??

What about the times i.e. Tuesday to Friday, every weekend & holidays that I don't do that journey.

Damnation DM I thought you were onto something then :bannana: but on reflection the legs fell off