# 225/50-17 Tires on an Eco Question



## sciphi (Aug 26, 2011)

I'm kicking around what I want to do for tires on my Eco when the time comes for new ones, likely next summer before my state inspection is up. The 2LT uses a 225/50-17 instead of the Eco's 215/55-17. The difference is about 1/2"-1" in tread on the ground and 0.4" less overall diameter on the 225's. The 215's have a diameter of 26.3" while the 225's are 25.9". In practical terms, that's 767 revolutions per mile compared to 780 revs/mile. So, the 225's will ride slightly stiffer, handle better, be a touch faster to accelerate, and decrease fuel economy by some amount. 

My goals with new tires are fuel economy first along with decent wet grip and road manners. So, sort of the opposite of what a 225 series tire would do for me. 

What do the rest of y'all think? Opinions besides my own are welcomed.


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## Starks8 (Jul 20, 2011)

So why not just buy another set of the eco tires you have now? Do they suck in the wet grip and road manner department? I would use Tirerack and do some comparisons on their website to maybe help you narrow the choices down.


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## XtremeRevolution (Jan 19, 2012)

I'm tempted to see what a 235/50 will look like on the Eco's 17" rims. Those would be 26.3"

Otherwise, I'd just go with a 225/55. For fuel economy, I'd rather go bigger rather than smaller. The difference in total diameter should be ~0.5". I highly doubt it will be enough to rub the fenders.


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## NYCruze2012 (Jan 16, 2012)

I'm glad someone has brought this up because I was thinking that same thought for my Eco. I wanted to go with the 225/50/17's as well. My friend Frank who has the RS package has those size tires and I really like the way they look. Does anyone have an estimate on how much it will impact mpg? Any guesses?

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## obermd (Mar 3, 2012)

Starks8 said:


> So why not just buy another set of the eco tires you have now? Do they suck in the wet grip and road manner department? I would use Tirerack and do some comparisons on their website to maybe help you narrow the choices down.


Sciphi and I had a thread last winter discussing the snow traction of the Goodyear Assurance FuelMax tires that ship with the ECO. Our conclusion was that in these tires are OK in the dry snow of the Rockies but not very good in the wet snow in NY State. I do think the Discount Tire and TireRack web-sites would be a good places to do comparisions and read reviews from other drivers. With new tires being released and older tire lines being retired, I always start at these two sites before buying new tires.


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## sciphi (Aug 26, 2011)

Starks8 said:


> So why not just buy another set of the eco tires you have now? Do they suck in the wet grip and road manner department? I would use Tirerack and do some comparisons on their website to maybe help you narrow the choices down.


They're a good tire in the dry. They have no grip in wet weather, though. 

When I went from 185/55-16 to 205/50-16 on our Fit, we lost 2-3 mpg. I'm guessing going from a 215 to a 225/55-17 would be about 1-2 mpg. Then again, the revs/mile are slightly lower, so reported fuel economy would go down while it would likely stay the same in real life. 

More to consider. Keep the thoughts coming!


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## XtremeRevolution (Jan 19, 2012)

sciphi said:


> They're a good tire in the dry. They have no grip in wet weather, though.
> 
> When I went from 185/55-16 to 205/50-16 on our Fit, we lost 2-3 mpg. I'm guessing going from a 215 to a 225/55-17 would be about 1-2 mpg. Then again, the revs/mile are slightly lower, so reported fuel economy would go down while it would likely stay the same in real life.
> 
> More to consider. Keep the thoughts coming!


That's something I'm wondering about. Your speedo and tach will be off due to the tire change, so with a larger tire, you'll actually drive farther but report less miles, thus looking like your fuel economy has dropped, but has it really? This is the reason I'm considering a 235 wide tire, but I'm not sure if it will look good on the Eco wheels. Might compromise handling a bit. How wide are the eco wheels? 7"?

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## elegant (Jan 6, 2011)

As part of your research, look into the weight of the tires you are researching (second the above Tire Rack site for that), for weight will be large factor in your MPG results.


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## XtremeRevolution (Jan 19, 2012)

elegant said:


> As part of your research, look into the weight of the tires you are researching (second the above Tire Rack site for that), for weight will be large factor in your MPG results.


This is very true. It's the main reason I'm considering just sticking with a factory size.

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## sciphi (Aug 26, 2011)

It would depend on the tire in question for weight and tread width. IIRC all the sizes "should" be about the same weight since the difference in tread is made up in the sidewall. 

I'm guessing that going with a slightly taller, wider tire would be a wash for fuel economy. The additional tread on the road will likely offset the reduced revs/mile. Ride quality would improve a touch thanks to the 2/10" taller sidewall. 

Looks like staying with OEM size is the way to go, at least for me.


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## XtremeRevolution (Jan 19, 2012)

From what I'm seeing on other websites, a 235/50/17 (I mistakenly said 235/45 earlier) would fit on a tire 6.5-8.5" wide. That's a rather large range. I am very curious as to how it would look on a Cruze Eco. The Eco's wheel is 7" wide, so it's within that range.

Edit: I looked it up. Here are 235/50/17 tires mounted on 17x7 wheels:

I really like that look. (click to enlarge)


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## sciphi (Aug 26, 2011)

That's a fairly aggressive look. I do like it. The fuel economy hit would scare me off, though. With gas only going up, the next set of tires for both cars will be oriented for efficiency. Our Fit has +0 sized tires, and while I like the look and performance, it's giving up some fuel economy.


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## obermd (Mar 3, 2012)

Have you looked at the Bridgestone Ecopia 422 tires? They're a low rolling resistance tires. I had real good experiences with Bridgestones in wet snow and slush while stationed at the Pentagon.


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## sciphi (Aug 26, 2011)

I've heard the EP 422's are horrible in the wet, so they got dashed off the list. They'd work nicely for areas that don't get a lot of rain, is what I've been told.

I'm trying to find the "perfect" tire, which is mythical. I'll have to compromise somewhere.


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## obermd (Mar 3, 2012)

Continental has a LRR tire that is getting good reviews on TireRack.


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## XtremeRevolution (Jan 19, 2012)

sciphi said:


> That's a fairly aggressive look. I do like it. The fuel economy hit would scare me off, though. With gas only going up, the next set of tires for both cars will be oriented for efficiency. Our Fit has +0 sized tires, and while I like the look and performance, it's giving up some fuel economy.


At higher PSI, I honestly don't know how much of a difference it would make in fuel economy. However, I know without a doubt that it's the size I will be running when these LRR tires get worn out. That would look awesome on a Cruze. I'd be willing to give up 1mpg to have a significant increase in traction and a much more aggressive stance. The difference in weight between the stock size and one of these is 2lbs. 

From what I'm seeing, any tire replacement over stock will have a reduction in fuel economy due to an increase in weight. Just something to keep in mind. Tire Rack is showing a 19lb weight for the oe tire, but a Hankook V4 Es tire in the same size, as an example, is 23lbs. Some tires in that size go up to 27lbs. Might be worth comparing the weight of each of these tires before buying.


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## NBrehm (Jun 27, 2011)

the 225/50/17 will be a negligible change on the speedo (about 1 MPH at 60), the 235/50 will be even closer, less than 1 MPH at 60, so you won't see much change in MPG from tire size there. What will hurt you is the added weight of the 235 tires, not a whole lot mind you, but the tread is the heaviest part of the tire so wider means more weight. I'd personally got with a Nitto Motivo in 225/55/17. They are a little bit heavier than the ECO tires but they also handle better in the dry and the wet. I've put 3 sets on cars now, a Cobalt SS, a Mazda 3 and an old school Talon TSi. The Mazda 3 had the aftermarket fuel max tires on it and talking to him he only lost about 1.5MPG average and, he openly admits, some of that may be due to more spirited driving now that the slightest bit of dirt doesn't send him slipping around on the road. Can't give you a snow report on them, we all have snow tires for the winter


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## XtremeRevolution (Jan 19, 2012)

I was finding that with most tires, the difference in weight was around 2lbs between 215/55 and 235/50. It wasn't too significant. I would imagine that increased drag and rolling resistance may have an effect though.

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## NBrehm (Jun 27, 2011)

XtremeRevolution said:


> That's something I'm wondering about. Your speedo and tach will be off due to the tire change



tach won't be off, Speedo and Odo will be


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## sciphi (Aug 26, 2011)

All the sizes we've been talking about so far will result in a 1-2% change in reported speed. Or, not enough to matter in the real world. Chevrolet themselves is saying a 1.5% change in speed from a 225/50-17 to a 215/55-17 is acceptable by putting the two different sizes on the cars. That 1.5% change smaller means at 60 mph reported speed the car's going 59.1 mph, while 1.5% larger means 60.9 mph. The speedometer will vary more than that anyhow as the tire wears. 

The diameter won't have as much of an impact as we're thinking. Tread width will have more of an impact on fuel economy and handling.


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## XtremeRevolution (Jan 19, 2012)

NBrehm said:


> tach won't be off, Speedo and Odo will be


Yeah, that's what I had meant to say, lol. I mixed up odo with tach, lol. 

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## Blue Angel (Feb 18, 2011)

Rolling resistance of a tire is affected by features that generate heat as the tire rolls. Generally speaking, how much the tread and sidewalls flex under load and how much they resist this flexing. Flex + resistance = work = heat.

Deformation of the tire's carcass is determined by the tire's construction (# of belts and plies, materials used etc.), the tire pressure and the load on the tire. Deformation of the tire's tread is determined by the rubber compound and the size/shape/pattern/arrangement of the tread blocks and the load on the tire.

A wider tire will not necessarily have a higher rolling resistance than a narrower one, but a significant increase in tire width does affect the frontal area of the car which increases drag.

A tire's construction is the biggest determining factor of its rolling resistance. Unfortunately, there is little published data and no official rating with units that customer's can use while shopping for tires, leaving them only with comparison tests done under various conditions with tire sizes that may not be the same as the ones they're shopping for.

The Wikipedia page has some basic information on this:

Low rolling resistance tire - Wikipedia, the free encyclopedia
Funny, there's a section that references the work Transport Canada is doing with LRR tires, the group I worked with. Their web page is here:

Low Rolling Resistance Tires - Transport Canada
I still keep in touch with the Engineers from the group. Not surprising, the Engineer in charge of the LRR testing drives a 2011 Eco 6MT and loves it.


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> Rolling resistance of a tire is affected by features that generate heat as the tire rolls. Generally speaking, how much the tread and sidewalls flex under load and how much they resist this flexing. Flex + resistance = work = heat.
> 
> Deformation of the tire's carcass is determined by the tire's construction (# of belts and plies, materials used etc.), the tire pressure and the load on the tire. Deformation of the tire's tread is determined by the rubber compound and the size/shape/pattern/arrangement of the tread blocks and the load on the tire.
> 
> ...


Great info! 

I believe that moving up to a 235 wide tire while maintaining the same diameter with an inconsequential increase in weight will not have a significant effect on the fuel economy of the tire over a 215 wide tire of the same make and model.


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## NYCruze2012 (Jan 16, 2012)

sciphi said:


> All the sizes we've been talking about so far will result in a 1-2% change in reported speed. Or, not enough to matter in the real world. Chevrolet themselves is saying a 1.5% change in speed from a 225/50-17 to a 215/55-17 is acceptable by putting the two different sizes on the cars. That 1.5% change smaller means at 60 mph reported speed the car's going 59.1 mph, while 1.5% larger means 60.9 mph. The speedometer will vary more than that anyhow as the tire wears.
> 
> The diameter won't have as much of an impact as we're thinking. Tread width will have more of an impact on fuel economy and handling.


Back when I had my 2004 Chevy Aveo sedan it came with 185/65/14's. I did not like the way the car handled that all. Also not to mention it had these crappy Hankook tires from the factory. I put on a set of BF Goodrich 195/65/14 G-Force Supersports and the car's handling improved dramatically. The only downside it was that changed my speedometer reading by 2 miles per hour. I know this because I checked it against my GPS and there definitely was a speedometer discrepancy.
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## Blue Angel (Feb 18, 2011)

More food for thought regarding a tire diameter change and spedometer accuracy.

The Eco's 215/55-17 tires are 26.3" diameter, as far as I know the largest of any tire offered on the Cruze (the 225/45-18 on the RS models, for example, is only 26.0" tall). Instrument clusters are not trim-specific, meaning that the same cluster and calibration is used in all models, save for the RS with its chrome trim and translucent backed gauges which is likely calibrated the same as the others.

My '12 Eco reads dead-on with a GPS-based speedometer app I downloaded to my iphone (the speed displayed on the DIC when setting the cruise control).

To figure out the % difference in speed, take your existing tire diameter (or revs/mile if known) and divide by that of the new tire and multiply by 100 then subtract 100. Example:

26.3" / 26.0" X 100 - 100 = 1.15%

In this example, if I changed from a 26.3" tire down to a 26.0" tire my ACTUAL speed would drop by 1.15% for a given DISPLAYED speed on the speedometer (actually going 1.15% slower than you think you are).


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## 6speed (Dec 7, 2011)

sciphi said:


> I'm kicking around what I want to do for tires on my Eco when the time comes for new ones, likely next summer before my state inspection is up. The 2LT uses a 225/50-17 instead of the Eco's 215/55-17. The difference is about 1/2"-1" in tread on the ground and 0.4" less overall diameter on the 225's. The 215's have a diameter of 26.3" while the 225's are 25.9". In practical terms, that's 767 revolutions per mile compared to 780 revs/mile. So, the 225's will ride slightly stiffer, handle better, be a touch faster to accelerate, and decrease fuel economy by some amount.
> 
> My goals with new tires are fuel economy first along with decent wet grip and road manners. So, sort of the opposite of what a 225 series tire would do for me.
> 
> What do the rest of y'all think? Opinions besides my own are welcomed.



My question is specifically dimension related, not tire brand, other sizes, compound or load/speed rating. This is so maybe I can have more options when it is time to replace the OEM Goodyears. On my 11 ECO, can I put on a 225/50R17 tire, even though it is 4/10 inch(10 mm) wider & 4/10 inch(10 mm) smaller diameter than the OEMs? Will I have any clearance issues turning or going down the road? I would really like an answer from someone that actually put this size on their ECO, because underneath, it may be different from a LS, LT or RS.


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## Poje (Aug 2, 2012)

The best tire for what you want is Michelin Primacy MXM4

As for the size, i would keep the same.

Im very performance oriented and i kept the stock size on my Cruze too.


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