Fabia VRS Mk I - fit 205/55/16 ?

[tlg]

Fabia VRS Mk I original tyres are 205/45/16. This size seems to have a fairly limited selection (I'm looking for something rated 'A' on fuel economy but the best I can find is 'C'). They also seem to be quite a bit more expensive than tyres in 205/55/16. So I was thinking about fitting something in the size range 205/55/16 instead (only the rear for now, but if successful I would do the same on the front (currently KU39s in 205/45/16 with about 50% tread remaining) later).

 

- Possible?

- Legal?

- Advisable?

- Would any tyre centre actually agree to fit a non-original size?

- Affect insurance?

 

The only problem I'm aware of is that it would slightly offset the speedo accuracy.

Edited 5 July, 2017 by tlg

[MartiniB]

@Tlg

205/45/16 vs 205/55/16

too big(6.9%) difference of diameter
https://tiresize.com/calculator/

 

producer recommends stay within 1%,
but i have exceed to 1.5%
https://www.briskoda.net/forums/topic/434519-change-of-wheel-size/#comment-4889926

https://www.briskoda.net/forums/topic/378824-low-frequency-boom-in-cabin/?page=3#comment-4886031

[KenONeill]

@tlg

- Possible? Yes

- Legal? No. For one thing it will mean that your speedometer will no longer read legally.

- Advisable? No. See under "legal" and "affect insurance".

- Would any tyre centre actually agree to fit a non-original size? Probably. They're also quite prepared to fit new tyres to the front despite what some tyre manufacturers claim about the safety of doing so.

- Affect insurance? Yes. Mostly because you may well be unable to find anyone prepared to insure you with these tyres fitted.

 

You could also look at 215/45 or 195/50 fitments.

[Warrior193]

Hi Tig, as MartiniB says, you may be increasing the rolling diameter a little too much going from the standard 45 profile to 55 - but it could only make your speedo under-read by less than 2%. I understand that UK regulations state that the speedo must not under-read at all, but so long as you were aware of the error, you shouldn't run into too many problems - just don't try to use it as an excuse if you overcook it through a speed trap! As an example, my MY16 Octavia 3,( standard tyres 205 / 55 / R16) runs on winter tyres (Michelin Alpin 5s) at 215 / 60 / R16 - which, I calculated, increase the rolling diameter at just under 5%, I checked the speedo via GPS and found that it read exactly correct for that new size of tyre, which indicates that the speedo reads around 5% high on the standard size.  

Edited 5 July, 2017 by Warrior193
missing punctuation

[tlg]

It sounds like it's not worth the risk then, so I'll probably stay with 205/45/16. I did check what was available in the other sizes Ken mentioned but didn't see anything really compelling. Incidentally how could you fit tyres with different widths from the wheel hub anyway?

Edited 5 July, 2017 by tlg

[KenONeill]

@tlg - I'm not sure what you're asking. All 16" tyres fit any 16" wheel in principal; in practice with your 16x6.5ET42s you need a tyre which is at least 165mm wide for a 16" rim, and can go up to a 235mm width subject to it being low enough profile. As long as you keep the standard wheels the tyre centreline will be in the same place relative to the hub mounting face.

[tlg]

How do you mount a tyre that is much wider than the wheel without it bulging out unacceptably when inflated?

Conversely if you try to mount a tyre much narrower than the wheel, will it seat properly?

[KenONeill]

@tlg - OK, I'm clear now. According to the tyre manufacturers (and indeed most car manufacturers) it is acceptable to fit a tyre when the tyre width is 70% to 95% of the wheel width (in your case 6.5"; I've already done the tyre width calculations for the limiting cases).

[skidpan]

Whats the problem with availability. 96 listed on MyTyres.

 

https://www.mytyres.co.uk/cgi-bin/rshop.pl?dsco=110&sowigan=So&Breite=205&Quer=45&Felge=16&kategorie=6&ranzahl=4&search_tool=standard&rsmFahrzeugart=ALL&suchen=Show+tyres

[tlg]

51 minutes ago, KenONeill said:

@tlg - OK, I'm clear now. According to the tyre manufacturers (and indeed most car manufacturers) it is acceptable to fit a tyre when the tyre width is 70% to 95% of the wheel width (in your case 6.5"; I've already done the tyre width calculations for the limiting cases).

 

OK, thanks for clarifying.

 

33 minutes ago, skidpan said:

Whats the problem with availability. 96 listed on MyTyres.

 

https://www.mytyres.co.uk/cgi-bin/rshop.pl?dsco=110&sowigan=So&Breite=205&Quer=45&Felge=16&kategorie=6&ranzahl=4&search_tool=standard&rsmFahrzeugart=ALL&suchen=Show+tyres

 

Yeah but the efficiency ratings are 'C' at best. Compare with 205/55/16 and there are plenty of 'A's, on average cheaper too.

[Rooted]

Why not forget the need for an 'A' Fuel Efficiency rating since you have a quite fuel efficient dirty diesel anyway and think on the handling and wet weather performance / safety.

[skidpan]

15 hours ago, tlg said:

Yeah but the efficiency ratings are 'C' at best. Compare with 205/55/16 and there are plenty of 'A's, on average cheaper too.

 

Remember that like the official mpg tests the tyre tests are carried out in a lab and in reality there is 1/2 of sod all difference between a A rated tyre and a F rated tyre. Between an A rated and a C rated I would doubt you would see any difference

 

To me wet grip is far more important and even then I refer to independent tyre tests which in most cases do not totally correlate with the labels. Tyres rated A for efficiency tend to be low rated for grip. Better to have a balanced tyre in my opinion.

 

As for cost if a tyre costs £10 more over 20,000 miles and 2 years that is 10 pence a week.

 

Far better to use the correct size, manufacturers tend to fit their cars with the correct sizes.

[KenONeill]

@tlg - Those EC tyre "performance ratings" are self-certified by the tyre manufacturers; an "AAA" rated "Yingtong Ditchfinder 3" may actually offer poorer fuel economy and wet grip than a "CCB" rated "PremiumBrand ChewingGum 2".

 

(Names are for illustrative purposes only, and bear no resemblance to any tyre manufacturer or brand that I know of)

[Warrior193]

8 hours ago, KenONeill said:

@tlg - Those EC tyre "performance ratings" are self-certified by the tyre manufacturers; an "AAA" rated "Yingtong Ditchfinder 3" may actually offer poorer fuel economy and wet grip than a "CCB" rated "PremiumBrand ChewingGum 2".

 

(Names are for illustrative purposes only, and bear no resemblance to any tyre manufacturer or brand that I know of)

Yippee, I'm gonna get me some of them ditchfinders and go drifting down the local Tescos - what was that brand ? - Yingtong ? 

[Fobba]

 My Fabia have now  215/45/16inch tyres and wheels are 16/7 and ET is 42.
i  have all so tested 205/50/16 which work all so nice.
And if il compare those tyres to orginall size i love both those size because driving comfort is so much better than orginall size.
I do not have to know every F...K pot holes  to my  back bones!!