17's decrease MPG. Discuss.

[PastyBoy]

Looking at swapping the standard 16"s for a set of 17" Spiders and am ready to accept the firmer ride and slightly heavier steering but am i going to expect a drop in MPG; and if so how big?

Not really that i'm that bothered but SWMBO who commutes 60miles a day might be considerably miffed if my want for wheels means her fuel costs double!

Any one noticed a huge drop?

[mannyo]

There will be a tiny difference, almost inperceptable. The difference will be due to the increased unsprung weight of the wheel.

[Callum]

Tell Beck to stop moaning:rofl:

It will be no different to her Ibiza!!

[andy2407]

What are the respective tyre sizes you are going to use?

[PastyBoy]

Tell Beck to stop moaning:rofl:

It will be no different to her Ibiza!!

A useful input from the Forest :P

Its already worse than the Ibiza due to the shorter top gear but i didn't wanna make it even worse for her!

What are the respective tyre sizes you are going to use?

they're coming from Phil_Monk's Faba so assuming 205/40/17.

Didn't think to confirm that yesterday when i said "yes please!!"

[KenONeill]

If you keep the same rolling radius I'd doubt you'd be able to measure the drop in fuel consumption. If if goes down 1% as usually happens, then you'd probably lose about 1%.

[VRS 203]

Didn't notice a difference swapping from 16's to 17's to 16's to 17's to 16's to 17's to 17's myself.

[PastyBoy]

Didn't notice a difference swapping from 16's to 17's to 16's to 17's to 16's to 17's to 17's myself.

helpful and

[andy2407]

If you keep the same rolling radius I'd doubt you'd be able to measure the drop in fuel consumption. If if goes down 1% as usually happens, then you'd probably lose about 1%.

I agree that if the rolling radius is similar it shouldn't effect fuel consumption much.

I would however say that a wider tyre could push it up a bit - hence the earlier question - although wider potentially equals grippier so not all bad!

[k3vin11]

Well I've just gone from 18 months on TT 6 spokes back to the standard fabia 16's, I have noticed that my average journey home from MPG has gone from 57ish to 61ish.

[Disco_Mikey]

The best i could get with 195/45R16 Michelins (wrong size i know, but the price was right ) was 64.8 mpg

Then upgraded to 215/40R17 Yokohamas, and couldnt get any better than 55-56mpg, but i put it down to the wider, stickier contact patch...

[VRS 203]

Well I've just gone from 18 months on TT 6 spokes back to the standard fabia 16's, I have noticed that my average journey home from MPG has gone from 57ish to 61ish.

Suppose that quite a bit of a difference.

Doing that on a regular basis you will notice the fuel consumption.

Interesting.

[VRS 203]

The best i could get with 195/45R16 Michelins (wrong size i know, but the price was right ) was 64.8 mpg

Then upgraded to 215/40R17 Yokohamas, and couldnt get any better than 55-56mpg, but i put it down to the wider, stickier contact patch...

And that is a fair difference also.

[andy2407]

The best i could get with 195/45R16 Michelins (wrong size i know, but the price was right ) was 64.8 mpg

Then upgraded to 215/40R17 Yokohamas, and couldnt get any better than 55-56mpg, but i put it down to the wider, stickier contact patch...

Thanks - that backs up what I said earlier about wider tyres making the difference.

[Fabby]

I changed my tyres on my 16" VRS alloys from 205/45/16 Eagle F1s to 195/45/16 Continentals and fuel economy on my usual work run went up from 42mpg to 47mpg. On my old 185/60/14's, I would get 51mpg most days.

The F1's had the best grip, but the Continental Sport Contacts are a good compromise.

It looks like at least some of the loss is down to higher levels of grip, so mpg will drop if the tyres grip more......

[devonutopia]

I remember going from 14" steels straight to 17s caused an economy drop, but that was more than likely due to tyre size, and my actual dstance travelled was fairly similar. I was going from "eco" 185 wide tyres to sport 205 tyres though.

[KenONeill]

Has anyone changed between 16s and 17s or vice versa, and retained the same tyre brand? I'm asking because changing tyre brand can be worth 5 to 10%, and all the "wider tyres used more fuel" people so far have changed brands.

[Chrispy]

Mannyo had the main point covered - unsprung weight. Rolling resistance shoudn't be much higher if you use decent tyres but with more metal and less rubber/ air going round the inertia of the wheel will be greater and thus require more grunt to turn. Luckily with a torquey car like the vRS it should hardly be noticable but worth bearing in mind.

On a side note I fitted M3 wheels to my 320i a few years back and it completely ruined the performance. Not that it was fast to begin with but with the bigger wheels on it was terribly slow. After talking to a few other forum members, they too commented on taking their 19's off etc and going back to standard size rims during a refurb etc and they were amazed how much faster the cars felt. But we're talking torque-less petrols here where the difference will be more noticable.

To add, many people taking their cars to the track put steelies on for the extra go, even if they did look a little daft.