Upsizing tire sizes with OEM Wheels

21483 Views 17 Replies 12 Participants Last post by DuffyF56, Mar 1, 2013

DuffyF56

Discussion Starter · Feb 28, 2013

Excuse me but using Search I have not been able to find this addressed. I have a 2012 Optima SX with Luxury Wheels. I have never been happy with the OEM Hankooks. They are noisy at best and the impact harshness is not to my liking. I would like to upsize the tires by going to a 50 series and a tad wider than the stock 225's say 235 or 245. I have not lowered the car. Are their fitment issues with this plan? I have no desire to destroy $200 plus tires by rubbing.

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avguytx

· #2 · Feb 28, 2013 (Edited)

If you stay within the same "ratio" range, you won't notice a difference in the speedometer. As far as which brand to go with, that's where I don't know as much about the tires for these as all I've bought in the last 9.5 years has been 20" tires for my Ram QC.

If the stock tire is the 215/55-R17, that makes these measurements:

8.46" tread width (215mm divided by 25.4mm)
4.65" sidewall height (8.46 x 55%....meaning 55% as tall as it is wide)
26.3" total height of tire (4.65" x 2 plus 17" rim)

Use those same ratios for calculating new tires and you can get an idea how much taller or shorter other tires will be in comparison. Such as a 225/55-R 17, 245/55-R17, etc. A 245 will be wider (9.65") which might potentially rub. But I don't know. Typically I used that ratio stuff when people came into out store wanting to go from 16" to 18" or taller and we tried to keep it so the speedometer readings weren't way off. You're usually good with about a 10% increase without too much difference.

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ohiomoto

· #3 · Feb 28, 2013

Read the http://www.optimaforums.com/forum/8-optima-wheels-tires-suspension/5110-wheel-tire-faq.html and then go to the tire size calculator at 1010tires.com (there is a link in the first post.)

DuffyF56

Discussion Starter · #4 · Feb 28, 2013

Already read the FAQ. I understand about ratios and tire sizes. Not too concerned about speedometer accuracy. Just trying to determine if they will rub or not.

cyclonegrayrick

· #5 · Feb 28, 2013

On the discount tire site, they list the 235/45-18 as an acceptable upsize for the SX. I went for the same original size 225/45-18 in a Michelin MXM4 thinking it would be quieter and better ride than the Hankooks. Not so, this tire in my opinion is as noisy as the optimo hankooks. I wonder if just upsizing to a 235 would help with the noise/ride as opposed to a 225.? Some guys on this site claim the MXM4 was a vast improvement over the hankooks, but I do not have that same opinion. Maybe they opted for the 235 series.??

DuffyF56

Discussion Starter · #6 · Feb 28, 2013

I want to go with a 50 series to get some sidewall back to improve impact harshness over the stock tires.

richysh

· #7 · Feb 28, 2013

There is a member who is running 245/45/18s. These will have thicker sidewalls. You might be able to find him/her if you search about it.

TurboSXL

· #8 · Feb 28, 2013

DuffyF56 said:
I want to go with a 50 series to get some sidewall back to improve impact harshness over the stock tires.

225/50 will not rub with the stock 18" luxury wheels. 235/50 may rub slightly over bumps or dips in the road, depending on your speed.

Vanbo

· #9 · Feb 28, 2013

I put 245 40 18 on my 2011 SX with no issues at all.

ohiomoto

· #10 · Feb 28, 2013 (Edited)

DuffyF56 said:
Already read the FAQ. I understand about ratios and tire sizes. Not too concerned about speedometer accuracy. Just trying to determine if they will rub or not.

First of all, it's not the speedometer accuracy you need to worry about. It's the radius of the wheel assembly and how it affects breaking performance and MPG. That said, if you want to know just how large of a wheel assembly you can use, look at some of the cars running 22" wheels on here. Find out what size tires they are using and use the calculator to compare them to the sizes you would like to run. I doubt you'll rub with any of the sizes you mentioned except mayby the 245/50-18 since you are on stock suspension, but I'm just guessing. Heck even the 245/40-19s that many of us have used are probably almost as big as some of those sizes.

Another tip is to use the 205/65-16 LX tire size as your base tire when using the calculator. It's the largest diameter tire our Optima comes with while the SX uses the smallest.

bh_trade

· #11 · Feb 28, 2013

I can't imagine that you would rub with any of the mentioned tire sizes. Many guys throw on Eibach springs (approx 1.25" drop?) with stock wheels and have no issues. Upsizing to 245/45/18 would only increase total tire height by roughly 3/4"

ohiomoto

· #12 · Feb 28, 2013

The OP is interested in the possibility of using a 245/50-18 which is more than 1-1/2" larger which might be even larger than any 22" tire used on our cars.

Tino Grad

· #13 · Feb 28, 2013

Go with a 245/45/18, Bridgestone Potenza RE760 Sport. Great grip, quiet, not a unidirectional tire so you can rotate F to R, L to R or even diagonally, they're not super soft so you can get decent tire mileage and you can get a whole set delivered for under $700.

avguytx

· #14 · Mar 1, 2013 (Edited)

205/65-R16 = 26.49" height

215/55-R17 = 26.31" height (EX)

245/45-R18 = 26.68" height

245/50-R18 = 27.65" height. Definitely taller.

Thor

· #15 · Mar 1, 2013

235/50/18 fits fine with some extra room. I ran that size for a few months before I ran into a brick and busted two wheels. I do miss the ride quality vs. the 20" wheels I'm running now.

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chance21

· #16 · Mar 1, 2013 (Edited)

I have 235/50 on 18 X 8 inch TSW Interlagos with 35 backspacing. At stock ride height when I hit really large bumps or potholes there would be occasional rubbing. This happened only on the front tires and only on the outside of the tires. I think the most important thing for you to figure out is backspacing and where that will put your wheel in the wheel well.

I like to use these sites for tire size comparison: rimsandtires.com or willtheyfit

SXexcess

· #17 · Mar 1, 2013

DuffyF56 said:
I want to go with a 50 series to get some sidewall back to improve impact harshness over the stock tires.

Part of the problem is the XL rating of the hankooks, which is not really needed but does add impact harshness IMO.

DuffyF56

Discussion Starter · #18 · Mar 1, 2013

Well...I only really have 3 complaints with my 2012 Optima SX.
1) Tires....noisy and impact harshness way too high for my liking and don't inspire confidence when driving. I hope to fix this with new tires once the OEM's are worn out.
2) Lack of powered 12V outlet in the center console that stays powered with ignition off. I know I can fix that if willing to modify the wiring.
3) The quality of the paint on the car which i feel is way too soft probably due to it being water based. The paint chips much too easily IMO. SOL here....just try to keep waxed and fix the chips as they occur.

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