What if any are the negative ramifications of using this tire size instead of taking the risk and using 234/45 on the stock rim? I definitely want to rid myself of those Pot 92s and it seems like 225/45 is very close to stock size and much cheaper than 225/50s while being safer than 235/45s.

 

http://www.miata.net/garage/tirecalc.html

 

Well, a bit of speedo error, and a harsher ride. Less sidewall, less flex, more bone jarring...this was an element I was not willing to live with when replacing my RE92's. I actually went to a 55 series tire.

 

I understand those concerns but I don't share them personally. I think the ride is so soft now that the increase in stiffness won't take much time to get used to. I think lowering springs and stiffer struts will produce a harsher difference than this change, but I could be wrong. I went from 70 series to 50 series on an old car of mine and loved the difference (although the section width increase was a major component) in handling, feel, and driveability. Thanks for your thoughts!

 

provides us an almost 30K car and can't step up and put 17 X 7.5 inch rims on it. I cannot decide on tires, if you stick to stock specs you have about 5 choices, most are very expensive. If you go to 225/45/17's you have a nice choice, but that's all I need is a lower profile tire and even more wheel well showing. I will not upgrade the 17 inch rims, I like the way they look. I will not lower my ride, I have the 5 yr/100K warranty and do not want to void it. Any info would be helpfull, I want to purchase new tires asap.

 

Nitto 450's in 225/50R17. They're priced right, look great, perform well, and according to my mechanic, wear like iron. I just purchased a set in 215/55R16 for my wife's 2K GXE Automagic. I payed $95.00 per tire locally (So. Cal.). So far, so good.

 

The speedometer error is only about 3 or 4%, probably not worth worrying about especially since it's in the direction less likely to win you an official roadside interview complete with flashing lights.

More important is the load capacity. The maximum rated load for 225/45-17 tire is anywhere from 50 to 150 lbs less than that for a 225/50-17, depending on whose tires you're looking at. That means a couple of things, actually. First, you'll need to run the 225/45's at more than 32 psi in order to have the same rated load as the 225/50's have at 32, probably something like 4 psi higher (which you can probably use as a differential if you run somewhat different pressures). The other is that, ultimately, the 225/50 is much better suited for carrying heavy loads (i.e. if your normal vehicle load includes 2 or more passengers and/or you commonly carry heavy cargo in the trunk).

Norm

 

Norm's point is well taken and begs the question. There are two excellent high-performance tire choices in our stock tire size of 225/50R17 . . . the Nitto 450 and the Michelin Pilot Sport A/S. The Nitto 450s run around $100 a tire and the Michelins run around $200 a tire. Certainly those tire choices serve most of our needs and fit within most of our budgets. So unless you want to purchase a wider set of rims or run tires that are out of spec for our stock rims, why not select from between one of those two tires?

 

links please, thx.

 

In a April 02 C&D article the Nissan speedos were reading 71.6 at an actual 70 mph. My GPS readings confirm this exactly.

 

http://google.yahoo.com/bin/query?p=...ires&hc=0&hs=1

 

Interesting, do you have any other speeds indicated and actual by GPS? That would be good to know.

 

Interesting, but not surprising given that the GXE tire size of 215/55R16 is probably the basis upon which Nissan speedos are calibrated. Do the math for yourself:

http://www.miata.net/garage/tirecalc.html

Actually, your point is worth posting in a separate thread, see5. I'll do that and give you credit. Thanks for bringing it to our attention.

 

I will run 40,50,60 during lunch and i think we will see it is linear.

 

My problem is just what you've said; there are ONLY 2 choices in that size. If I go 225/45 or 235/45 there are dozens of options of better tires than these 2 choices and most of them are LESS than the Michelin price. I think I'll do some load rating searching and see if I can find a 225/45 with a close rating I'd go for it. Ideally I'd like to have a Dunlop SP 9000 or Pilot Sport; something in the ultra high performance arena. Guess I'll probably just wait until I have enough cash to buy rims and tires and do a Plus 1 upgrade to keep loads and tire sizes versus rim width in proper, accepted ranges. Thanks for the info and opinions!

 

Hey, is this the Nissan GPS? Where does it show the current speed? I'd be interested to try this too in my i35...

 

No, Streetfinder laptop IPAQ/Laptop system.

 

hey did u ever pick a tire size? i'm interested in 235/40, 225/45/...how much different will the ride be?

 

The nittos suck....think i'll get good mileage (got like 25k now) but remember that you get what you pay for. nuff said.