How will i ride on 245/45/18 tires??

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Nov 13, 2008 | 07:36 AM
  #1  
Had a little mishap, only way out is to slap on some 245/45/18 tires on it.

How will it ride?
Anyone ever try that?
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Nov 13, 2008 | 08:00 AM
  #2  
No clue...i just know we shud all be on 40's.
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Nov 13, 2008 | 08:16 AM
  #3  
what was on it before?

the ride difference/acceptablity will be relative to what you've been used to.

i'm running 235/45/18s which replaced my stock rims with 225/55/16s.

the ride with the shorter sidewall is a bit more harsh but completely acceptable.
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Nov 13, 2008 | 08:24 AM
  #4  
i had 245/ 40/ 18

Now : 245/ 45/ 18

The guy at the shop said its fine, ill see when i get there.
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Nov 13, 2008 | 08:34 AM
  #5  
i had 245/45/17. bumpy but i don't mind especially that cornering was like in a ferrari
say good bye to good mpg though.
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Nov 13, 2008 | 09:24 AM
  #6  
serg oh serg what did you do?
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Nov 13, 2008 | 09:52 AM
  #7  
If anything, your fronts might rub turning...the backs might rub as well.

S
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Nov 13, 2008 | 11:21 AM
  #8  
+1 for rubbing, sidewalls r large but if ur in a pinch shouldnt be that bad
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Nov 13, 2008 | 04:15 PM
  #9  
aren't tires with a sidewall of 40 and wheel radius of 18 the same height as stock (205-65-15)?
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Nov 13, 2008 | 04:51 PM
  #10  
Quote: aren't tires with a sidewall of 40 and wheel radius of 18 the same height as stock (205-65-15)?
Yes and No. The 40 isn't the actual size of the sidewall, it's the aspect ratio. That is the ratio of the rim diameter to tire width. So if the rim diameter stays fixed, as the tire gets wider, the aspect ratio must get smaller to keep the close to the same wheel diameter.

Example:

Stock wheel diameter with wheel and tire is 25.5". A 235/40/18 tire has a total wheel diameter of 25.4". Off by only a tenth of an inch. Say you want something a bit wider...but keep the aspect ratio of 40. So lets use a 265/40/18 tire. Your diameter is now 26.3". It's almost an inch bigger! You would need to lower the aspect ratio, so the more appropriate tire would be a 265/35/18 tire..which has a diameter of 25.3".

So in this case of maximaserg, he's going from a 245/40/18 tire...to a 245/45/18 tire. He's going from a total diameter of 25.7 inches to 26.7 inches. Likely he will deal with rubbing issues.


Hope I explained this right. Easiest way to understand this is to mess with a tire size calculator. The one I use has a visual, and you can see what happens with different sizes.

http://www.miata.net/garage/tirecalc.html
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Nov 13, 2008 | 08:18 PM
  #11  
The rubbing depends on what offset you run on the wheels. I had to roll the fenders a little to fit the G35 wheels and R compounds. You will def feel every bump in the road.
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Nov 14, 2008 | 07:34 AM
  #12  
had 245/45/17 and it rode like hell, now i have 245/40/18 and it rides like hell upgrade itself, sometimes i think lucifer himself is playing around in my suspension and tires. I can live with the bad ride with the amount of grip i have.
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Dec 5, 2008 | 05:20 PM
  #13  
i just picked up some g35c 18's. The rear has 245 45 18. It rubs on dips. Im changing them to 225 40 18's
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Dec 5, 2008 | 05:43 PM
  #14  
I'm probably going to upgrade to some 225 / 55 / 17 for the front and 225 / 50 / 17 for the rear.

Any input? Thanks.
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Dec 5, 2008 | 05:53 PM
  #15  
like a cruise ship...
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Dec 5, 2008 | 05:53 PM
  #16  
when i had my black wheels i had 245/45/18 and it rode pretty good. but handling was awesome like stated above it was like a Ferrari.
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Dec 5, 2008 | 06:03 PM
  #17  
Quote: like a cruise ship...
What is that suppose to mean?
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Dec 9, 2008 | 12:53 PM
  #18  
im about to upgrade my rims to some m35 18s it came with 245 45 18 from reading here i seen it will rub on bumps has anyone rolled the fenders and did it help at all???? and how about when people are in the back seat did it rub all the time
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Dec 10, 2008 | 04:00 PM
  #19  
Quote: What is that suppose to mean?
like a ship...lol sloppy
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Dec 10, 2008 | 04:06 PM
  #20  
mine didnt rub at all
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Dec 10, 2008 | 05:00 PM
  #21  
Quote: like a ship...lol sloppy
What do you mean sloppy? Whats a good combination then?
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Dec 11, 2008 | 07:49 PM
  #22  
so the tires a little streched...a little...but thats going to be a little stiffer ride
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