Tyre Size Alternatives for Giulietta QV R18's

[mattyc82]

I have seen an older thread from 2015 on this but it appears OP's question on tyre size got answered as tyre type in the thread.

I bought the 2014 QV with almost 30,000km and the tyres hadnt been rotated.  Swapped front/rear and 7,000km later the rears are a poofteenth above the wear marks on the inside/camber.  Front tyres getting close.  Looking at new tyres and was wondering what is the maximum size people have put on the R18 rims without causing rubbing issues.

Speedo runs about 3% slow to a GPS as well.  Its not that bad (my Nissan Navara ran a full 10% slower to GPS - no wonder everyone was up my arse) but would be happy make this difference 0% as well.

Its mainly driven by the wife and any protection a larger tyre can give to gutter rash on the rims is also a bonus.

The standard size is 225/40/R18 and was wondering if 235/40/R18 or 225/45/R18 have had rubbing issues.  Its only just the next size up in both cases but I dont want to be stuck with a set of four wrong sized tyres.  Leaning towards the 225/45's.

UPDATE:
So they didnt have the 225/45/R18's I wanted so settled with 235/40/R18's.   They dont rub at full lock.  No vibrations or humms or anything.

I do think they look HEAPS better too. The 225/40 profile just looks too thin to me.

The increase in speedo reeding vs GPS is a little better.  ~2km/hr @ 100km/hr. 

[wopalx]

I have seen an older thread from 2015 on this but it appears OP's question on tyre size got answered as tyre type in the thread.

I bought the 2014 QV with almost 30,000km and the tyres hadnt been rotated.  Swapped front/rear and 7,000km later the rears are a poofteenth above the wear marks on the inside/camber.  Front tyres getting close.  Looking at new tyres and was wondering what is the maximum size people have put on the R18 rims without causing rubbing issues.

Speedo runs about 3% slow to a GPS as well.  Its not that bad (my Nissan Navara ran a full 10% slower to GPS - no wonder everyone was up my arse) but would be happy make this difference 0% as well.

Its mainly driven by the wife and any protection a larger tyre can give to gutter rash on the rims is also a bonus.

The standard size is 225/40/R18 and was wondering if 235/40/R18 or 225/45/R18 have had rubbing issues.  Its only just the next size up in both cases but I dont want to be stuck with a set of four wrong sized tyres.  Leaning towards the 225/45's.

Mine has 235/40r18 on it. Car was a one owner lady driven and every wheel has gutter rash so I don't think the extra size did much.

They don't rub but it tramlines badly, I'm due for new rubber and will likely go to the stock size.


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[bazzbazz]

I am just curious, but why would you want to put higher profile tyres on the 18" rims?

Do you find the standard 40 profile ride harsh and you are looking for a more comfortable tyre ride??

I can advise, but first need to know what it is you are trying to achieve.

Baz

[poohbah]

If you go for higher profile rubber on 18s, you are going to further mess up the accuracy of the speedo and odo. Not to mention a having a good chance of all four wheels rubbing on the guards and inner wheel arches.

So if you really just want a bit more sidewall, you probably need to drop a rim size to at least 17inch.

(PS - I think most speedos are calibrated to read higher than actual speed - 3% is pretty good)

[poohbah]

For what its worth, a member on here posted photos of a Giulietta with Giulia QV wheels and tyres presumably without rubbing (19" rims with 245/35ZR19 tyres). So the extra width must squeeze under the guards okay.

But obviously the tyre profile is 35, so the outer circumference would be pretty much the same as 18" rims with 40 profile.

http://www.alfaclubvic.org.au/forum/index.php?topic=16224.0

[mattyc82]

If you go for higher profile rubber on 18s, you are going to further mess up the accuracy of the speedo and odo. Not to mention a having a good chance of all four wheels rubbing on the guards and inner wheel arches.

No, the speedo runs slow to GPS, so bigger rolling diam will fix it.

[poohbah]

Fair enough. Hope you find the rims/tyres/stance you are after.