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Old 06-19-2013, 05:24 AM   #1
Scooby Newbie
Member#: 214658
Join Date: Jun 2009
Chapter/Region: MWSOC
Location: Rolla, MO
2005 Wrx wagon

Default 235/40r18 poplularity reasoning.

Hello Nasioc

quick background.... Im looking into some 18x9 for my wrx wagon and I know that to keep similar wheel diameter, gearing, and all that jazz, the tire should be around a 225/40. BUT.....

My question is that I seem to see ALOT more 235/40 around and on alot of the cars I see rocking 18x9. So what is the reasoning.

I know I read and looked into it some but getting confused.

So it will have a
1. better contact patch.
2. taller sidewall by about 4mm.
3. speedo off by like 1mph.
4. less stretch then a 225

BUT besides personal decision I see that the 235 will also increase your gearing. making them longer. Which from all what I gathered online sucks for our already poor 5-speed.

I do like the longer gearing for cruising on the highway though.

But I guess my real question is... does the 235 make for a better choice over the 225 on an 18x9 wheel.

Just wanting to hear some feedback from the community.

And as with everything on the internet gotta take it with a grain of salt. But that is just what I got from gathering and searching and doing some number crunching.

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Last edited by Prendatram; 06-19-2013 at 05:25 AM. Reason: TYPO
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Old 06-19-2013, 12:34 PM   #2
Patrick Olsen
NASIOC Supporter
Member#: 120
Join Date: Jul 1999
Chapter/Region: AKIC
Location: Where the Navy sends me...
1997 Legacy 2.5GT
1996 Impreza coupe


The change in gearing is around 1%, so your 3.90:1 final drive would effectively feel like a 3.85:1. You're more likely to feel slower acceleration due to the heavier wheel/tire combo than due to that tiny change in gearing.

So my answer is yes, the 235/40 is the better tire. My other answer is that a 255 would be even more better, and that I wouldn't bother buying 9" wide wheels if my car wouldn't let me fit appropriately sized tires on them, but that's just me.
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Old 06-19-2013, 12:37 PM   #3
Scooby Specialist
Member#: 31519
Join Date: Jan 2003
Chapter/Region: MWSOC
Location: Glenview, IL
2017 Babby Duramax
2011 Lotus Evora


Because people are doing it wrong (like you). Pick the tire you want/need, then find appropriate wheels to suit it. Don't pick a wheel and then try to find the smallest/cheapest tire you can for it. There's no reason at all to buy a 9" wide wheel and run 225/235 tires. Stick with a 7.5 or 8 for tires that narrow.

Useful information: http://legacygt.com/forums/showthrea...sion-4426.html
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Old 06-19-2013, 04:28 PM   #4
Scooby Guru
Member#: 4414
Join Date: Feb 2001
Location: Dublin, CA
2002 WRX Sedan
Midnight Black


If you want your car to look cool, then go big.

If you want your car to be FUN, then put the smallest diameter tire you can get on there. The 2.0L WRX benefits GREATLY from shorter gearing. SO MUCH MORE FUN with short gearing.

I didn't know this and initially was using tires near stock size. Knowing what I know now, 235/40/17 is the TALLEST tire I'd ever recommend for a 2.0L WRX with a stock gearbox. 215/40/17 is even more fun. If you have tons of money, you can do this "the right way" by swapping in a transmission that is better suited to the rest of the car and use whatever size tires you want. But that costs bank. Tires are the cheaper way to accomplish the same thing.

The handling may be slightly better with wider tires, but the 2.0L has a huge lack of drivable torque and the 5MT is a pain to shift into first reliably in a motorsport situation. The result is you end up in 2nd gear waiting for power on many corners. Plus driving around town is sometimes annoying and just not fun. The gearing difference of small tires more than makes up for any loss of grip from taller / wider tires, and more importantly greatly increases the general fun factor of driving your car.

The later model 2.5L 2008-2013 body styles accommodate much larger wheel and tire combos and the 2.5L has MUCH less issue with low end torque thanks to the longer stroke, AVCS and increased displacement. As a result, advice from someone with a 2.5L may not be sound for a 2.0L.
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Old 06-20-2013, 08:12 PM   #5
Scooby Newbie
Member#: 214658
Join Date: Jun 2009
Chapter/Region: MWSOC
Location: Rolla, MO
2005 Wrx wagon


Ok thanks for replies. And negative comments arent necessary about size tire.

I do like flushness. Thats why I was looking at the 18x9. Just seemed more popular with 235.

My other tire choice im looking at is 245/40 on a 17x9. That is more square and no stretch. So all you people that hate on buying for looks please dont comment. I know im buying for looks.

But I been looking for more performance too so that's why I asked if one is more preferable over the other.

And to the poster above me would you recommend a 225/40/17 to help to shorten the gearing.

Also should of stated it but my two tire combos I have had in past are the stockers on 205/55/16 and 225/40/18.
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