I'm going from 17" OEM Rims with tires: 225/50R-17 and 235/50R-17, to OEM 18" (which spec for 225/45-18 and 245/45-18. I am going to go with All Season Tires, which as some of you may know are hard to find in 2_5/45, while 2_5/40 are much more common. My question is, since there is only one tire I can find that is All Season and fits OEM 18" specs (Avon M550 which is actually a high rated tire), am I limited to that? Would I be able to get by with 225/40 and 245/40s, or would I get a negative impact from doing so? Will this all be a problem since I am going from the different 17" tires as well?

I need help fast, and the tire section is much slower than this, and I plan to order these tonight, so any help is appriciated. Thanks!

 

I'm running 245/40-18 Michelin Pilot Sport All/Season on the front of my G, and I love them. They are almost the exact same rolling size as the stock 225/45-18 tire.

I wouldn't advise running 225/40-18. The stock 225/45-18 already looked stretched on the stock rim. Make the side wall any smaller, and you'd practically be driving on the rim. The 245/40-18 looks perfect.

 

So what are you running for rears? They don't make 225/45s for rears for any all season tires but the Avons, which I am still considering, but I would rather go with the Pirelli P-Zeros or Toyo Proxes 4, but those dont come in 225/45. Only options are combinations of 225/40, 245/45, and 245/40..

Thanks

 

I"m running 275/40-18 on the rears, but I have aftermarket wheels. Most of the All/Season tires come in 245/45-18, which is what you should run on the rear. From what I remember, it was only the 225/45-18 that was hard to find.

So in summary, (in case you were confused), you should run:

Front: 245/40-18
Rear: 245/45-18

 

Thanks. Will I run into any problems running those since they are out of spec, like VDC or ABS or anything? I'm thinking about going with the Avons since they actually do come in 225/45, but I'd feel more comfortable going with a brand like Continental Conti-Extremes or Pirelli P-Zeros, but neither come in the spec size, so I was concerned.

Thanks for your help!

 

Rather than fussing over "sizes" which are surprisingly inexact, I would recommend, for any tire you have interest in, using the manufacturer's website and any datasheets (often PDF files) you find there, to choose a tire that matches your stock "revolutions per mile" For the G, 775 and 804, r&f respectively, or thereabouts. I'm surprised to read that you want all season tires. A quick spin thru this forum would indicate that the G is not a car that responds well to all season tires ("no seasons" as many would say, in this application)

 

I just swtched over from OEM 17in tires to OEM 18in 225/45/18 and 245/45/18 BF Goodrich g-Force T/A KDW NT and am totally in love with them. They have a real agressive tread pattern that is different from most others. Give them look and I think you will be happy with them

 

The difference is that the 40's are shorter by about 3.5%, and smaller circumferance, resulting in more revolutions/mile.
This will probably upset the VDC.
C.

 

No you won't have any problems. I've been running them for about 7 month now without any problems. 245/40-18 is less than 1% smaller than the stock size. The general rule of thumb is 2-3% is ok, so you're good there. And the speedo is connected to your tranny, which is connected to the rear wheels, so it will have 0 effect on your speedo.