well guys i finally got them. i went ahead and got Dunlop SP-5000's in a 235/45R17. first of all i have to say that they are awesome. they are very quiet and handle extremely well. i like them a whole lot more than the Nitto NT450's i had before.

here are some pics

http://www.nissanx.net/gall/Dario

 

Assuming your wheels are at least 7.5" wide and your tires are in-spec as a result, I can't help but wonder why you decided to purchase 235/45R17 tires instead of 245/45R17s. Would you be good enough to explain the logic of your decision to me, Dario? Thanks in advance.

(PS: If anyone else with 7.5" wide or wider wheels decided to purchase 235/45R17 instead of 245/45R17 tires, please feel free to weigh in here. I suspect Dario is going to need all the help he can get in coming up with a reasonable explanation for his decision.)

 

Is that the higher profile tire? Maybe he wanted the ride comfort?

 

The aspect ratio is a percentage of the width of the tire. When the aspect ratio remains constant (as in the number 45 in this case), the wider the tire, the higher the profile. Thus a 245/45 tire will have a higher profile than a 235/45 tire. Having said that, the 245/45 tire is still considered a low-profile tire. It's also wider and generates less fender gap than a 235/45 tire. It's therefore more appealing from a visual perspective. But most important, the 245/45 tire produces less of a speedometer error than the 235/45 and it's still in spec on 7.5"-wide rims.

Purchasing 235/45R17 tires is a perfect example of the herd mentality at work. Those who purchase them do so because that's what everybody else does. They're too lazy to look up the information on their own even though the data is readily available in the FAQs. Thus they tend to make uninformed purchase decisions.

Whether your tires are in-spec for your rims or out-of-spec for your rims, it never makes sense to purchase 235/45R17 tires when 245/45R17s are available from the same manufacturer. And those who tell you otherwise either do not know what they're talking about or they're unfamiliar with elementary arithmetic. (Some of the brigher bulbs in our chandelier have actually tried to convince people that 7.5" really isn't 7.5". Somehow, 7.5" is narrower with a 245/45 tire than with a 235/45 tire. Go figure!)

 

i'm running 235/45 on my 7.5 rims. the reason: i do some autocrossing. although the 245 are still in spec, speedo error is less, etc, i'm thinking of the times i drive the car up to the limits. although it's in spec, i decided to stay safer and get a smaller tire and reduce my chances of rolling my tires off. if i wanted 245's, i would have bought at least an 8 inch rim. just my opinion...

 

Right, craaaazzy. But you're on the edge with either the 235/45 or the 245/45 with 7.5" rims. Remember, 7.5" is 7.5" no matter how you slice it or dice it. And the Tire and Rim Association would not specify 7.5" as the minimum acceptable width for 245/45 tires if they didn't think it was safe to do so.

 

better safe than sorry is my motto. else i would have gone w/ 235's on stock rims...right? haha, just kiddin. i know ur a big proponent of staying in spec.

 

Still, your point is well taken. I'm aware of individuals on the org that autocross with 235/45R17s mounted on their OEM 7.0" wide rims. Although that combination is clearly out-of-spec, I'm not aware of a tire failure occurring as a result of it. On the other hand, such failures may have occurred and those who have experienced them may simply be too embarrassed (or too dead) to admit it.

 

well to answer ur question my stock tires (GXE model) were 215/55R16 and when i used that information and entered in the tire size i purchased it said that when i travel 60 im traveling 60 on the tire calculator. Then when i entered in a 245/45R17 it said i would be traveling 60.9 instead of 60. so based on that i went ahead and stayed with the 235's. hope that answers it for u.

 

one might do 235 in lieu of 245, that being gearing...yes, you might put a bit less rubber on the road but you do in fact shorten your gearing a wee bit compared to the 245s...other than that I agree w/u..if you can have it, use it -the width I mean...

 

Yup. Just for laughs and giggles, compare the OEM tire size of 225/50R17 against the 235/45R17. Then compare it against the 245/45R17 and let me know what you come up with.

 

So, my question is: Does Nissan install different speedo pinions for the 16" spec SE vs the 17"? Depending on the OEM, one can be mislead to either 235 or 245 as being more 'accurate'.

 

Just for comparison, Bridgestone specs listed by Tirerack:

rim range meas rim section tread diam rev/mi
215/55VR16 5.5-8.5" 6.5" 8.5" 6.9" 24.6" 861 (RE-92)
225/50VR17 6-8" 7" 8.9" 6.7" 25.9" 804 (RE-92 Nissan)
235/45ZR17 7.5-9" 8" 9.3" 8.1" 25.3" 823 (RE-730)
245/45ZR17 7.5-9" 8" 9.6" 8.6" 25.8" 807 (RE-730)

So, the 16" is spec'd closer to the 235, 225 17" to the 245. Big diff in rev/mi though. Hmmm.

 

yeah u were right on that comparison, but then again i didnt have 225/50R17 i had 215/55R17 which was on my GXE. thanks for the help though and i understand what u mean now.

 

geez...just let it go..so what? some people bought tires that you don't agree with? don't start making fun of people and spoiling people's mood...it's not like purchasing a set of 235s instead of 245s greatly affects our cars...besides, having a fat side wall isn't really all that sport look either.

 

Based on your argument, most people with OEM rims would replace their 225/50R17s with 225/45R17s if they want to remain in spec. My suspicion is that very few do, however.

I think it's safe to say that most people on this forum purchase the widest tires they can for their rims. For some, tire width is so important that they're even willing to run out-of-spec tire/rim combinations to gain a lousy 10 mm of tire width. If I'm correct, why would any of them purchase 235/45R17 tires when 245/45R17s require precisely the same minimum rim width?

 

so the only thing ur arguing about is the speedo error?

 

YEAH !

btw, enjoy your tires dario.

 

if you really want my opinion, the side wall on 245/45/17s are too fat. yeah, you'll have little bit less fender gap and all, i'd have bought a SUV if i wanted fat tires.

besides, 245s are a bit heavier than 235s too

 

thanks guys.

i was told i could go a 245 profile but when i looked at them side to side with the 235 i think the 245's looked too fat.

thanks for comments guys

 

OK, point taken! But if I were going to go with an oversized tire, I'd definitely opt for a 245/45R17 rather than a 235/45R17. It's wider, it's a little more compliant, it does a better job of filling in the fender gap, and it generates less speedo error when compared to the OEM tire size of 225/50R17.

Enjoy the ride.

 

hmm this is very useful info. had i not checked the 5th gen forum i would have kept believing that 235 was the best (meaning closest to spec/speedo calibration) size to choose on a 17" rim. i did know from reading motortrend or C&D that 235 was smaller in overall diameter. just a thought. i wonder if i bought super lightweight rims if they would help my 60' and 1/4mi times lol.

 

Right, VQdriver. I'm constantly amazed at how often people make purchase decisions based on misinformation, particularly when the facts are readily available on the org and they're easy to find.

Laziness is the root of all evil!