Hello everyone, i have just bought my first Skoda, a 2017 Octavia Vrs TDI DSG, love the car so far.

 

I have a quick question for anyone who can help, my car has the 19” alloys on with 225/35 tyres, i want to put all season tyres on and have noticed that any decent ones are only available in 235/35, can i fit this size to my wheels without any problems?

YES. Actually gives your standard 7.5J alloy a bit more rim protection. Plenty of members on here already running this width/profile tyre.

In a nutshell, yes it'll be fine. 

 

Long answer - it'll make your speedo read slightly higher (but we're talking similar differences to 225/40R18, which is a standard size), you arguably should inform your insurance, the extra width may have a small negative impact on rolling resistance / fuel economy. 

34 minutes ago, Kenai said:

it'll make your speedo read slightly higher

Could be wrong, but why would a width change make it read higher? (I understand the reasoning for depth). But as it's on 19's already and not 18's, would this not have been configured within the EMS / speedo etc as OEM?

 

Totally agree with other points re: 235/35 is fine to use, and negative impact on rolling resistance / fuel economy, but it's negligible in my experience.

Width effects height of the tyre as your side wall is a percentage of width, so if width increase so does the height. 

Every day's a school day! Cheers Will bear in mind.

Thanks for the replies guys, i will get some 235 all season tyres on in the next month or so.

 

Adding a bit of extra rim protection isnt going to hurt either, those wheels look to be kerb magnets.

Anyone done the maths to work out exactly how much higher speedo will display?

22 minutes ago, Ads230 said:

Every day's a school day! Cheers Will bear in mind.

To add a bit to what @Gmac983 said, on a particular model you'll generally (but not always) find all the standard wheel and tyre size combos result in almost identical rolling circumferences, so swapping between different standard sizes should have little to no effect on speedo calibration.

 

The Octavia gets... 

205/55R16 - 1984mm

205/50R17 - 1999mm

225/45R17 - 1991mm

225/40R18 - 2002mm

225/35R19 - 2009mm

 

Swapping to... 

235/35R19 - 2032mm

 

So you can see why switching to the 235/35R19 isn't a massive deal in terms of speedo change but it is far enough outside of the window the other tyres are in to need to be aware of it. 

 

All that said, I did originally state it the wrong way round, the speedo will under read, ie. you'll be travelling faster than it shows by just over 1%.

Edited 22 October, 20196 yr by Kenai

@Stoofa

The difference will be enough to make the speedo more accurate since it is not from the factory with OEM tyres on.

*EDIT, 'nearer to being accurate than from the factory on the OEM tyres.'

 

Edited 22 October, 20196 yr by Roottootemoot

7 minutes ago, Kenai said:

To add a bit to what @Gmac983 said, on a particular model you'll generally (but not always) find all the standard wheel and tyre size combos result in almost identical rolling circumferences, so swapping between different standard sizes should have little to no effect on speedo calibration

 

That's exactly what I did with my old citroen grand picasso before I decided to run all seasons on its standard 17" size.

I purchased 16" steel wheels and higher profile tyres to match the entry level model sizes but maintaining as said an almost identical overall rolling diameter. 

31 minutes ago, Stoofa said:

Anyone done the maths to work out exactly how much higher speedo will display?

 

70mph on 225/35 will read 71.09mph on 235/35

Perfect - thank you.

Silly question - do you tend to get any "hassle" from tyre fitters on having this fitted?

I will need at least two new tyres within the year, I've got a little bit of sidewall damage (no, there are no cords showing, it'll be fine) which will almost certainly fail an MOT, plus the new from factory are starting to wear.

 

If I order them at the slightly different size, am I going to get "These won't fit" or won't they even notice as they will just go on?

Am I safe driving with two at one size and two at another?

 

Cheers all.

It'll depend on the particular fitters, I've heard of some that give it the "we can't do that, we'd be liable if you crash" spiel and others that just do what you ask them for. Watch out also for some places saying they can't check or adjust your tracking due to the lane assist camera. 

 

As for running two different sizes, my only concern would be whether the ABS / TPMS would get confused, as you'd potentially have a fair discrepancy between worn 225s that have lost a few mm of tread and new fully treaded 235s. Whether it'd be enough to cause issues I don't know for sure. It's not something I'd personally do. 

 

I've stuck with 225/35R19. With Michelin doing £100 cashback on 4 19" tyres this month I got a full set of PS4S in the standard size for £123 each, changing to 235s was only about £3 per tyre cheaper where I went. Not life changing amounts. 

25 minutes ago, Scot5 said:

 

70mph on 225/35 will read 71.09mph on 235/35

Other way round, while it still reads 70mph you'll actually be doing 71.09mph.

 

That is of course subject to the built in inaccuracy @Roottootemoot mentioned earlier. Your speedo legally has to ensure it doesn't under read so they're factory set to over read slightly. In reality it'll just bring your speedo closer to reading what you're actually travelling. 

I run bigger tyres than OEM on every vehicle i have, summer or winter and know which is more accurate to the actual speed being driven.

Important when you have points on your licence and lots of average speed cameras around and Mobile Camera vans.

42 minutes ago, Scot5 said:

 

70mph on 225/35 will read 71.09mph on 235/35

Other way round, surely? A bigger tyre will have to rotate more slowly for a given actual speed. Slower rotation means a reduced indication.

Since the speedo is already around 5% optimistic, a bigger wheel will reduce this error. What you want to avoid, obviously, is a speedo that reads less mph than you are actually doing. So not too big!

4 hours ago, Mike_D said:

Thanks for the replies guys, i will get some 235 all season tyres on in the next month or so.

 

Adding a bit of extra rim protection isnt going to hurt either, those wheels look to be kerb magnets.

As previously mentioned, Costco are doing £100 off 4 tyres (19") from the 4th Nov for 3 weeks