Yeti mpg ( Winter tyres)

[lfc958]

Since we have put the smaller winter tyres on the mpg has increased by 3 - 4 mpg.

 

Anyone else found this ?

 

Also, given the rolling diameter is smaller seems odd ? I was wondering if it was the tyres

 

 

[trundlenut]

Are they narrower too? If so it's not surprising, less rubber in contact with the road therefore less resistance.

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[Ryeman]

Are they higher profile tyres giving the same rolling circumference?.

[33q]

Smaller rolling diameter so more revolutions to achieve the same real distance.

Check that your daily commute has not become a greater distance

I suspect you are recording a greater mileage than actual hence your mpg appears to have improved.

Of course lower resistance may so may be playing its part

[ejstubbs]

What he said.  The majority of the difference is down to the difference in the circumference of the tyres making your odometer readings a bit high.

 

Your speedo will be reading high(er) as well.  I've calibrated mine against GPS with both normal (OEM size) and winter (smaller).  With the OEM size tyres on 70mph by the GPS shows as 119kph on the Maxidot.  With the winters on its 125kph.

[lfc958]

They are 205/55/16  Skoda alloys,  the Normal ones are the standard 17 inch Origami alloys.

 

Must Try the MPH against GPS to see what the real difference is.

[Guest]

They are 205/55/16 Skoda alloys, the Normal ones are the standard 17 inch Origami alloys.

Must Try the MPH against GPS to see what the real difference is.

That is the same set up as myself, and the speedo is approximately 5mph out. I have to remind myself at the beginning of each changeover of the discrepancy, especially at the beginning of the winter changeover and I'm wondering why everyone else is zooming past me.

I cannot comment on fuel consumption as I've gone from a 40 mile each way motorway summer journey, to a 2.8 mile each way town and A-Road winter journey.

[lfc958]

So it begs the question if the mile reading on the Odometer will be the same for the same journey on the different wheels ?

[Urrell]

They are 205/55/16  Skoda alloys,  the Normal ones are the standard 17 inch Origami alloys.

 

Must Try the MPH against GPS to see what the real difference is.

This is the difference, nearly nothing.

16" and 17" recommended sizes.

205 x 55 - 16" at 60 mph will be standard at 60 mph

225 x 45 - 17" at 60 mph will be reading 59.77 mph.:  Overall diameter is 2.2mm larger but with 12mm of usable tread there is negligible difference in rolling diameter and speed reading.

[dbg400]

This is the difference, nearly nothing.

16" and 17" recommended sizes.

205 x 55 - 16" at 60 mph will be standard at 60 mph

225 x 45 - 17" at 60 mph will be reading 59.77 mph.:  Overall diameter is 2.2mm larger but with 12mm of usable tread there is negligible difference in rolling diameter and speed reading.

 

Has the FL changed sizes? The 17"s on my Yeti are the standard 225/50. There was around 3.8% difference in rolling circumference between them & my 205/55/16 winter wheels. The 16"s put the odometer out (an extra ~four miles in every hundred) and the speedo - it would read progressively worse the faster you drove, with 70 on GPS showing 77/78 on the speedo.

[lfc958]

Thanks, getting some really useful info.

[fatzy]

If your summers are 225/50-17, your winters should be 205/60-16 to match the circumference.

Also: winter tyres has a little higher rolling resitance due to the rougher tread pattern and softer rubber.

[Llanigraham]

If your summers are 225/50-17, your winters should be 205/60-16 to match the circumference.

Also: winter tyres has a little higher rolling resitance due to the rougher tread pattern and softer rubber.

 

Have you looked at any winter tyres lately?

They do not have a rougher tread pattern, just more snipes.

[ejstubbs]

So it begs the question if the mile reading on the Odometer will be the same for the same journey on the different wheels ?

 

Er, no.  That's the point.  With the smaller diameter winter tyres on, the car thinks it's going further for each revolution of the wheel than it really is.  Hence the odometer will read high, and hence the MPG will be (more than usually) over-optimistic.

 

Where else could the car get the mileage being used to calculate the MPG figure shown on the Maxidot?

[33q]

Anybody used the winter tyre setting that is available on maxi dot

[dbg400]

Anybody used the winter tyre setting that is available on maxi dot

Isn't that just for setting a speed dependant warning in case the speed rating on the winter tyres is below that of the car's top speed? I suppose that's fairly academic in the UK at least, as you'd be hard pressed to find tyres with a rating of less than 70mph!

[33q]

Not sure ?.....I only spotted it the other day

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[fatzy]

Have you looked at any winter tyres lately?

They do not have a rougher tread pattern, just more snipes.

Like mine? Yes, the transverse snipes is what I call rougher pattern, made for traction. The combination of softer rubber and all these tiny snipes will make higher rolling resistance. More energy will be spent by the micro bending of the sniped pattern. Summer tyres of today are focused on energy saving by 4-5 continous longitudinal treads.

[Llanigraham]

Isn't that just for setting a speed dependant warning in case the speed rating on the winter tyres is below that of the car's top speed? I suppose that's fairly academic in the UK at least, as you'd be hard pressed to find tyres with a rating of less than 70mph!

 

Correct!

[Brijo]

Has the FL changed sizes? The 17"s on my Yeti are the standard 225/50. There was around 3.8% difference in rolling circumference between them & my 205/55/16 winter wheels. The 16"s put the odometer out (an extra ~four miles in every hundred) and the speedo - it would read progressively worse the faster you drove, with 70 on GPS showing 77/78 on the speedo.

 

The UK16"SpecialBuildClub have OEM 215/60/R16 rubber.  My GPS 70mph = speedo 75 (give or take). 

[lfc958]

As i found the winter setting in the MFD is just a speed warning that you set for the rating of the tyres.

 

It is a but pointless really for the L&K as it has speed warning setting anyway, 

 

I am getting some interesting info .

[freedie]

Ah! But you could do what I do and set the winter tyre speed setting to beep at say 95mph and the speed setting to beep at 100mph. If you try really hard you can get from one to the other quite quickly and listen to the dee-dah-dee-dah sound (until you realise it is getting louder as you drive...

[lfc958]

Now that would be irritataing , could even set at 69 & 70 MPH so you dont break the law speeding  

[ejstubbs]

Now that would be irritataing , could even set at 69 & 70 MPH so you dont break the law speeding

 

I'd calibrate the speedo vs GPS first, so that you set it at a true 70mph.

 

I had my speed warning set for a while (at 80mph rather than 70mph - sorry, officer ).  SWMBO didn't like it so I turned it off.  She recently got a ticket for doing 84mph on the M74...

[lfc958]

 i bet she blamed you for switiching the warning off  :p