Hi all. I'll start by saying, I apologise for another tyre/rim post, however I figured the nice guys n gals at the AMC will be able to help (the advice you all gave for my recent exhaust upgrade was brilliant). My question is this, is there any issues with putting 20" wheels on our beloved 380 or on FWD cars?

I ask because I'm currently have 18" Advanti Chopper rims with 235/45/18 Faulken Azenis FK453 (tyres are only 5 months old). The rims came with the car and I don't think they look that great. Anyway, I asked the local tyre store about fitting 20" Vertini rims and tyres. The tyre guy said he could if I really wanted, but it's not a great idea. He told me 20" wheels on a front wheel drive car just gives a horrible ride, horrible driving experience and mumbled something about makes it harder finding the right size offset or something. He went on to say, 20" for rear wheel drive cars is much better and that going to 19" for my 380 would not only keep it legal (I remember reading somewhere, in Perth you can legally go plus 2 for your wheels) but would give a far nicer ride and drive.

I've seen a number of cars, 380's and Aurions for example, who get around on 20s. Is this guy telling me the truth or not?

20s will fit on a 380 no problem, as long as the rims are no wider than 9" and the tyres are no "taller" than 245/30/20 (that's with Kings Lows in the rear).
I had this combo on my old 380 for a few months, 245/30/20 on 20 x 8.5 rims, with (IIRC) +39 offset.
The ride was horrible, they tramlined like crazy, and they vibrated at anything over 100 km/h despite three attempts to re-balance them.
It turns out that both the rims and the tyres were out of round and unfixable. Probably because they were relatively cheap.
Good quality 20" rims and rubber will cost you a packet and IMHO they are not worth it. I ended up with 19s, so much better in every way other than pure looks and bling.

That 2 plus rule has been removed for some time now. The rule is to keep the overall diameter within specs.

Ok, wow interesting. Thank you for that. Looks like the bloke was telling the truth. Guess I've some thinking to do then, stick with my 18s and just change the rims or go to 19s. Obviously, the bigger rims are purely for looks but I'm not keen on spending a heap of cash just so it looks sweet but drives like a pig. I didn't realise the plus 2 rule had gone out the window a while ago. Looks like I'm a bit out of touch :(

Just out of pure interest, what size are people running on their 380's 18s, 19s? I saw a vid yesterday of 2011 Galant with 22" rims and lambo front doors...... unique would be a nice way to put it :confused:

His advice is kind of confusing.

Yes he's right - less tyre sidewall will mean a harsher ride, and a bigger (hence heavier) wheel will blunt performance (because of the effect that the unsprung mass has).

But these issues aren't restricted to FWD cars. And the difference between 19" and 20" isn't going to be massive.

Finding something with the right offset isn't an issue as 380s use the same offset as late model Falcons. Plenty of wheels and tyres to choose from.

If it were my car I'd go for a set of 19s, but there's plenty of people over the ages running 20s on 380s without complaint.

I would suggest going for a slightly larger tyre than standard - 245/40/19 and 245/35/20 respectively. Extra sidewall means a bit of extra comfort (and protection from potholes) and the larger diameter will fill the guards better. In a similar vein I run 245/45 tyres on my 18" rims for that very reason.


as long as the rims are no wider than 9" and the tyres are no "taller" than 245/30/20 (that's with Kings Lows in the rear).
I think you just had bad luck on the tyre front. My 245 tyres are 23mm larger in diameter than 245/30/20, and are only 2mm smaller than 245/35/20s and I have no issue on the back (although I have had my guards rolled). They will occasionally rub on the bolts in the front guards if there's a bump big enough to bottom the car out, but no issue at all on the back.

The issues with 19s are that there are a lack of wheels in that size and henceforth lack of tyres. When my 18 RJR wheels were warped going through a large pot hole, I wanted to go 19 but could not find ones I liked and the tyres were fairly expensive (although that was partly because I needed 95+ load rating tyres). Didn't have the money to go 20 so went for a new set of 18s.

The issue with going up in overall diameter too much is one, that you are more likely to get caught speeding and two, if you have an auto, the torque converter would lock up at higher speeds than normal, causing it to use more fuel.

I must admit, I was a little confused when he mentioned larger sized wheels were a problem for FWD cars? The lower profile equals a less comfortable ride I can understand but that would be the same for any low profile tyre. I was prepared to accept a slightly harsher ride but having it blunt performance is something I'm not as excited about.

If I'm honest, it hadn't even crossed my mind about the larger, heavier wheel effecting performance. Neither did it even enter my mind about the torque converter being effected either. It would appear that apart from looking absolutely amazing with 20s on, I am starting to wonder why anyone would want to (except for the big brake upgrade reason of course).

Maybe then, I'll just grab a new set of 18' rims with use my current tyres (only 5 months old) and with the money I'd save I'll owe you blokes a beer. lol

I've just been reading this http://www.caranddriver.com/features/effects-of-upsized-wheels-and-tires-tested
Interesting read, and it's basically saying what you knowledgeable folk have said.