It increases running costs as larger diameter tyres are more expensive and a 2% variation is an alteration to speedometer accuracy isnt it???

No, it is not. Regarding the cost of the tire it was mentioned here that 18" doesn't have to mean very expensive. As an example - Potenza RE 050 A 225/45 R17 94Y costs £88.90 vs 225/40 R18 92Y £106.90 - eye watering £72 difference for 4 tires . Moreover - this 18" tire will be cheaper than my veccy 16" (I paid £126 per tire a year ago) .

Regarding 2% in the diameter variation - well, I assume you have to change your tires very, very often and even 1mm thread wear is unacceptable for you because it influences your speedometer accuracy . Don't be paranoid. I don't like 18" on 40 profile as I drive very often on some rural roads with very uneven surfaces with many potholes. Other than this can't fault 18" alloys...

Edited 30 June, 201213 yr by lmb

I don't like 18" on 40 profile as I drive very often on some rural roads with very uneven surfaces with many potholes. Other than this can't fault 18" alloys...

That's fine and a valid argument, but please don't cloud that argument with inaccuracies like:

It increases running costs as larger diameter tyres are more expensive and a 2% variation is an alteration to speedometer accuracy isnt it???

No, it is not. Regarding the cost of the tire it was mentioned here that 18" doesn't have to mean very expensive. As an example - Potenza RE 050 A 225/45 R17 94Y costs £88.90 vs 225/40 R18 92Y £106.90 - eye watering £72 difference for 4 tires . Moreover - this 18" tire will be cheaper than my veccy 16" (I paid £126 per tire a year ago) . I don't like 18" on 40 profile as I drive very often on some rural roads with very uneven surfaces with many potholes. Other than this can't fault 18" alloys...

Even by your reckoning the 18" tyre IS dearer than the 17".

You can always find an oddball size that will buck this trend, BUT compare sizes LIKE FOR LIKE and generally the larger the diameter of rim, the dearer the tyres will be - maybe not by a great deal but they are still dearer.

That's fine and a valid argument, but please don't cloud that argument with inaccuracies like:

Even by your reckoning the 18" tyre IS dearer than the 17".

You can always find an oddball size that will buck this trend, BUT compare sizes LIKE FOR LIKE and generally the larger the diameter of rim, the dearer the tyres will be - maybe not by a great deal but they are still dearer.

I compared what sits on Superb - SE vs Elegance. It is dearer by £72 BUT bear in mind this is £72 you have to spend every 2-4 years (I change tires on one axle every 2-3 years) so you need to dive it by factor of 2-4. £36 pounds a year - come on - it's a laugh, wouldn't you agree? I'd say it's a common sense .

If not - why not to buy greenline - it's saves you a great deal of many compared to £36 . And it comes on smaller 16" tires. Not mentioning the difference in price

Edited 30 June, 201213 yr by lmb

I agree the difference is not huge... but to say they are not dearer is wrong.

As for what model to choose well we all look at them to see what suits our budget, needs and desires. I looked into the Greenline (for economy) but there were options that i wanted (rather than needed) that were not available on the Greenline (heated windscreen springs to mind) so discounted it early on.

Larger wheels look better, but other than to clear the brakes (which on a OE Skoda 16" is ample) there is no need to go larger than 16".

I compared what sits on Superb - SE vs Elegance. It is dearer by £72 BUT bear in mind this is £72 you have to spend every 2-4 years (I change tires on one axle every 2-3 years) so you need to dive it by factor of 2-4. £36 pounds a year - come on - it's a laugh, wouldn't you agree? I'd say it's a common sense .

If not - why not to buy greenline - it's saves you a great deal of many compared to £36 . And it comes on smaller 16" tires. Not mentioning the difference in price

You really like to argue and then confirm my statement

As a rule 18" tyres ARE more expensive than 17" tyres comparing like for like and changing the rolling radius of the tyre often alters the accuracy of the speedometer , both are valid statements

Whether either of these are reasons that will impact someones decision is irrelevant

Personally i change all my tyres at the same time, i always fit premium tyres Eagle f1 assy on my Superb and Falken 452's on my Octavia both in 18" as thats the size of wheel both cars left the factory with

You really like to argue and then confirm my statement

I'm just trying to point that thou these statments are TRUE have absolutely no value!

If you are trying to prove that 18" are dearer - yes, they are but this is just a silly fraction of costs you spend on a petrol. Doing 10k miles a year you will spend ~1300 (@6l/100km) and 18 "extra" quids you need to spend on tires is less than 1.5% of the petrol cost. Not to metion other costs, such as servicing, insurance, road tax. This £18 will simply be in the region of 0.5% of the money you spend on keeping your car on the road. Of course, we can talk numbers different way and say 18" are dearer by ~18%... wow.This is critical factor that should help you to decide... this is what I call common sense. In terms of raw numbers 18" are dearer but when you put it into wider perspective there is bearly any difference.

Similar with 2% size variance - that is absolutely legal and is very simlar to the natural wear that happens.

But yes, if these are the reasons why 18" are rubbish than you are 100% right... differences on level of 1-2% decide if something is good or bad - got no more questions .

O, I forgot - I suppose you drive something like citigo because everything is a waste of money, is dearer and doesn't make sense .

Let's try to be resonable and don't judge someting by the margins of the cost of cars that we use :sun:

Edited 30 June, 201213 yr by lmb

This topic is funny, it's the only car forum I've ever seen where people are wanting the 17"s over the 18"s, admittedly I used to spend my time on various BMW forums where the huge rubber band effect was the preferable option with rubbish run flats.

Hope you manage to get your car ordered, I'm sure there are people on here that would be more then willing to swap. As for the cost of tyres I personally think they are a bargain given I got 14k out of the fronts. £136 a tyre was more then reasonable from black circles, I'm used to paying £200+ though on the old run flats so anything cheaper is a bonus.

I compared what sits on Superb - SE vs Elegance. It is dearer by £72 BUT bear in mind this is £72 you have to spend every 2-4 years (I change tires on one axle every 2-3 years) so you need to dive it by factor of 2-4. £36 pounds a year - come on - it's a laugh, wouldn't you agree? I'd say it's a common sense .

It's 36 quid per year if you would be running the exact same tyre in 17 vs 18 and you got the exact same life from them. But given how sensitive low profile tyres are to alignment, very few wear flat and evenly to get the usual life. The other problems are with wear rating. 18's are usually softer and faster wearing.

Here where tyres are dearer and petrol cheaper (comparatively) there are a lot of vehicles on the road with higher tyre cost than petrol cost (per km driven). Most of these vehicles are running 18's or bigger and struggling to get 30,000km from any given tyre, even less when you replace them as a pair or set when the first one fails the 6 monthly safety check (similar to your MOT).

But I do agree with the greenline call. Perfect solution for those wanting lower running costs all-round.

Edited 1 July, 201213 yr by Kiwibacon

I love it when people who drive road cars want better tyre cornering stiffness than F1.

Please do explane as I don't understand?

i always fit premium tyres Eagle f1 assy on my Superb and Falken 452's

Falken are not classed as a premium tyre, however, if someone can tell my what a premium tyre is I'd love to read it.

rubbish run flats.

Due to EU tyre noise regs of 2009 to get a rwd car to handle its best to have run flat's or a 19" tyre or bigger, to get a fwd to handle its best to have at least 18". This is why BMW use run flat and manufacture's wheel's get bigger in dia. Todays 18" tyre has a softer sidewall that a 1990's 13". .

Please do explane as I don't understand?

People who fit 18" wheels and tyres often claim it is for performance reasons and they *need* the extra sidewall stiffness. This is *******s as F1 cars make do with 13" wheels.

Due to EU tyre noise regs of 2009 to get a rwd car to handle its best to have run flat's or a 19" tyre or bigger, to get a fwd to handle its best to have at least 18". This is why BMW use run flat and manufacture's wheel's get bigger in dia. Todays 18" tyre has a softer sidewall that a 1990's 13". .

That makes no sense. I can get any 13/14/15/16" tyre and deform the sidewall with my thumb at normal operating pressures. I cannot do this with 18" tyres as the low height of the sidewall makes them very stiff. This stiffness is why they transmit so much more noise to the car. I have not been in any car with 18's which didn't have a lot of road noise. But where I live road surfaces are rougher chip and the noise levels higher.

19" wheels are not about handling.

People who fit 18" wheels and tyres often claim it is for performance reasons and they *need* the extra sidewall stiffness. This is *******s as F1 cars make do with 13" wheels.

That makes no sense. I can get any 13/14/15/16" tyre and deform the sidewall with my thumb at normal operating pressures. I cannot do this with 18" tyres as the low height of the sidewall makes them very stiff. This stiffness is why they transmit so much more noise to the car. I have not been in any car with 18's which didn't have a lot of road noise. But where I live road surfaces are rougher chip and the noise levels higher.

19" wheels are not about handling.

Track tyres and road tyre's are not quite the same.

Before 2009 you would have been right with regard to 19" tyres not been required for handling, when I say handling I do not mean grip levels, but latral movement within the tyre sidewall, with regard to your thumb test this must clearly mean I have no idea what I'm talking about, sorry. .

Track tyres and road tyre's are not quite the same.

This whole thread is about large wheels on skoda superbs. Not track tyres and not rwd cars either. But it all still applies except for the lack of people buying a superb for track-days.

Before 2009 you would have been right with regard to 19" tyres not been required for handling, when I say handling I do not mean grip levels, but latral movement within the tyre sidewall,

This is exactly the sidewall stiffness I have mentioned many times now.

with regard to your thumb test this must clearly mean I have no idea what I'm talking about, sorry. .

Do you not see the connection?

People who fit 18" wheels and tyres often claim it is for performance reasons and they *need* the extra sidewall stiffness. This is *******s as F1 cars make do with 13" wheels.

I went for 18" wheels because they were what was supplied by Skoda as standard on my car. I believe they should know best about what is the ideal tyre and wheel combination for optimal ride, handling, and comfort. If they want to differentiate between trim levels by fitting different wheel options to the various versions, I'm sure they wouldn't do that if was too detrimental to the car. The whole thing is a compromise between all the different characteristics, including the aesthetic of just filling up the hole in the side of the car! I'm a bit too old to be voluntarily pushing my car to anywhere near the handling limits on the public road, and I don't plan on doing any track driving in the near future.

I went for 18" wheels because they were what was supplied by Skoda as standard on my car. I believe they should know best about what is the ideal tyre and wheel combination for optimal ride, handling, and comfort.

But mainly customer perception. Because if you are paying more, you want it to look better. Right?

I have tried to follow this thread but have obviously missed something. There is no way I could fit smaller wheels/tyres on my car because of the brakes. I can't even get my car wash mitten between the caliper and the rim so if you wanted smaller wheels then you would need smaller brakes and so different mounting hardware etc. etc. I am not sure many production lines would have that flexibility but there is a lot I do not know; as I am told frequently.

I have tried to follow this thread but have obviously missed something. There is no way I could fit smaller wheels/tyres on my car because of the brakes. I can't even get my car wash mitten between the caliper and the rim so if you wanted smaller wheels then you would need smaller brakes and so different mounting hardware etc. etc. I am not sure many production lines would have that flexibility but there is a lot I do not know; as I am told frequently.

What size wheels and brakes do you have? What size is your spare?

18" wheels. Brakes would be 1/2" smaller on the front but possibly 2" smaller on the rear, I can't find the diameter details at the moment but they are vented front and rear AND they stop!! Spare is a "motorcycle" wheel and I have ordered a proper wheel/tyre to replace it as the current one would be (almost) useless in Australia.

18" wheels. Brakes would be 1/2" smaller on the front but possibly 2" smaller on the rear, I can't find the diameter details at the moment but they are vented front and rear AND they stop!! Spare is a "motorcycle" wheel and I have ordered a proper wheel/tyre to replace it as the current one would be (almost) useless in Australia.

16inch wheels would fit. No point in arguing with kiwi as he's got a bee in his bonnet about it cos he's kerbed his own 18s and of course totally irrelevantly f1 cars have 13inch wheels.

This thread is past tedious now and has gone full circle more times than an f1 wheel.

18" wheels. Brakes would be 1/2" smaller on the front but possibly 2" smaller on the rear, I can't find the diameter details at the moment but they are vented front and rear AND they stop!! Spare is a "motorcycle" wheel and I have ordered a proper wheel/tyre to replace it as the current one would be (almost) useless in Australia.

If you haven't upgraded the brakes they should be 312mm front, 282mm rear and 16" wheels will fit without any issues. It may look tight, but they are designed to work with 16's and upwards.

I agree about the uselessness of space-saver wheels. Fine if you are only 70km from a replacement, useless for everything else. The Superb's sold here have a full size spare.

You are aware that F1 cars use the tyre as a major suspension component, yeah? And they have inboard brakes so they don't need to fit under the wheels.

Best off comparing to BTCC cars - big wheels, big brakes, low profile tyres.

You are aware that F1 cars use the tyre as a major suspension component, yeah? And they have inboard brakes so they don't need to fit under the wheels.

Yes I am aware of that.

Road cars also use the tyre as an integral part of the suspension. But the point is simple. Those who consider that any wheels smaller than 18" cannot meet their handing needs, must have a hell of a commute.

Best off comparing to BTCC cars - big wheels, big brakes, low profile tyres.

Good point. Which wheels are VAG cars in BTCC running?

Apparently Alfa are running 17's.

These SEAT BTCC wheels are 17's also: http://www.racecarsdirect.com/listing/42529/works_seat_sport_btcc_alloys_17_x9_with_235_610_17_slicks.html

But the point is simple. Those who consider that any wheels smaller than 18" cannot meet their handing needs, must have a hell of a commute.

The point was simple before 2009, and an 18" may have offered poorer handling than a 16" due to the lack of give within the wall maybe making for a skitish car, but since the EU reg change in 2010 this is no longer the case as the sidewall of a modern 18" is far softer, it has to be to comply. A 2012 19" sidewall will have approx. the same level of give/flex as a 2008 15". Lets not go into runflats through.

Good point. Which wheels are VAG cars in BTCC running?

Apparently Alfa are running 17's.

These SEAT BTCC wheels are 17's also: http://www.racecarsd..._17_slicks.html

As said, you can't compare a road tyre that must comply with different rules and regs to a track tyre, which will have have stronger sidewalls than a road tyre. .

And the cars are smaller than a Superb...

The point was simple before 2009, and an 18" may have offered poorer handling than a 16" due to the lack of give within the wall maybe making for a skitish car, but since the EU reg change in 2010 this is no longer the case as the sidewall of a modern 18" is far softer, it has to be to comply. A 2012 19" sidewall will have approx. the same level of give/flex as a 2008 15". Lets not go into runflats through.

You've said this several times now and it's still making no sense. EU regs cannot bend the laws of physics. Low profile tyres cannot and do not have the same sidewall give as taller profile tyres. To claim a 19" tyre has the same give flex as a 15" is just bizarre. Do you have any external information sources to backup your claims?

The EU regulations did not specify tyre construction or sidewall stiffness, they only concern performance criteria which a tyre maker can meet any way they wish. I have not found any 17/18 or upwards tyre with sidewalls that are as soft, flexible or have as much give as any 15" tyre.

Even 15" light truck and van tyres have softer sidewalls with more give than 18's of the same OD. It's not about EU regs, it's about the geometry and how a sidewall of half the height has less than half the flexibility.

Page 72 of this report has nothing good to say about "Plus sizing" of tyres and rims: http://ec.europa.eu/enterprise/sectors/automotive/files/projects/report_tyre_road_noise2_en.pdf

It goes as far as saying that Plus Sizing is undoing many of the advancements made in tyre and wheel technology.

These comments are found under the chapter "Trade-off with fashion and styling".