Tire Sizes

[RogerMcDoger]

My Superb is currently running 235/40R19 tyres. I've seen some discussion about some people moving up in width, to something like a 245/40R19 instead. Is that a doable thing? The price for the tyres seems a lot better(and the range is bigger too) for the 245's. What are peoples thoughts?

[Tuan]

Find out the width of the rim and put it in here:

403 Forbidden

This does not account for scraping the fenders etc. ie in stock or lowered form, but more so what is physically possible to go on the rim.

Speedo will also read different but you probably already know this.

[RogerMcDoger]

Find out the width of the rim and put it in here:

403 Forbidden

This does not account for scraping the fenders etc. ie in stock or lowered form, but more so what is physically possible to go on the rim.

Speedo will also read different but you probably already know this.

Ahh good info. Thanks for posting.

[Tuan]

Also, if you ask a tyre shop what you can/should/are allowed to get, you will possibly get different answers.

I was after 225 tyres and one Bob Jane said, "we have 235s and they will be fine and cheaper" whereas another said, "I would not suggest putting 235 and stick to 225 OEM tyres".

Bleh

[skodian]

Also, if you ask a tyre shop what you can/should/are allowed to get, you will possibly get different answers.

I was after 225 tyres and one Bob Jane said, "we have 235s and they will be fine and cheaper" whereas another said, "I would not suggest putting 235 and stick to 225 OEM tyres".

Bleh

I personally will go for the right size as the variation in the tyre circumference may impact the the speedo reading.

Depending on which state , according to RMS in NSW state (http://www.rms.nsw.gov.au/documents/...si-09-rev4.pdf)

The wheel and tyre must be contained within the body work or mudguards (including any flares) when the
wheels are in the straight ahead position.



If the wheels are listed on your car’s tyre placard or in the owners handbook then the tyres you fit must be those

listed on the placard or in the handbook for these wheels.

[ZR36]

Check out Online Wheel and Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit
It compares existing set up and the new set up with diagrams and "out readings" pretty cool sight

Note there is a common miss conception around the "profile" measurement the /40 in the 235/40R19 is not the height in mm its a percentage. And this is what affects your rolling diameter.

In saying all that your engine an transmission is designed with the specified size. Changing that would not only affect the speedo reading but your gearing ratios efficiencies all sorts of things. Small changes will have minimal impact though.

[ZR36]

Everyone wants a bit of extra width though, right

[RogerMcDoger]

Everyone wants a bit of extra width though, right

That's what I've been told

It was all so I could save a bit of cash on the tires Looking at the prices now though 235's are cheaper than 245's. I would have sworn it was opposite the other day. Oh well.

[dArK5HaD0w]

I wanted to go from 225/40/18 to 225/45/18 on my Octavia, but BobJane said no deal.
I wanted to increase the tyre wall thickness for a softer quieter ride.

[Tuan]

I wanted to go from 225/40/18 to 225/45/18 on my Octavia, but BobJane said no deal.
I wanted to increase the tyre wall thickness for a softer quieter ride.

According to the speedo error calculator 100km/h will actually be 104 km/h (despite the built in error cars come from factory with) ... Going from 225/40/18 to 235/40/18 it'll only go from 100 to 101 km/h. 403 Forbidden Don't know why it says 403 forbidden, but the link works Shop probably thinks it's too much difference hence won't sell to you.

Probably a much bigger change in rolling diameter when changing the aspect ratio.