Right Winter Tire Size??

Hi Guys,

 

I went in yesterday to FINALLY put my winter tires on (been soo mild in toronto recently). I went in wanting the snowtech vikings in the size 205/55/16. The guy I went to said I should be using 225/55/16's so it'll reflect correctly on my odo and speedo. I took the jump and bought the 225's (more expensive too!), and was wondering if I made the right decision?

 

Browsing around here, everyone seems to be using 205's for winters. I'm just concerned I might have bought the wrong sized tire. BTW. I have a 2.5i sedan SE.

That doesn't sound right.

 

Why wouldn't he recommend buying a 205/60/16? They're almost identical in diameter to the 225/55/16.

Let me guess. He had 225/55R16 and didn't have 205/60R16? What they have in stock is what they recommend.

I have 215/55/16 on my 2.5i and they are about right. I wish I had gone with 205's rather than 215's but 55/16 is the correct tire regardless of how wide it is. It's actually about an inch taller than the stock 205/45/17(I'm sure this varies with different tires). Any taller and you start to lose space in the wheel well.

 

http://i19.photobucket.com/albums/b179/aboone1970/car2.jpg

Thanks for the replies.

 

So, basically, the guy gave me the wrong tire however it may be okay? Is that what everyone's saying? I just don't want this to mess up my bearings or alignment.

55 is the Aspect Ratio. Section width / Section Height

 

So if you select a tire with more width then you will also increase the section height (or the overall diameter of the tire) if they have the same aspect ratio. If the overall diameter of your tire is not close to the OEM tire then you will get incorrect mileage reading on your odometer.

 

OEM 205/50R17:

Overall Diameter = 25.07 in = 636.77 mm

Revs per Mile = 829.6

 

205/55R16:

Overall Diameter = 24.87 in = 631.69 mm

Revs per Mile = 836.3

 

225/55R16:

Overall Diameter = 25.74 in = 653.79 mm

Revs per Mile = 808.0

 

So neither the 205/55R16 nor the 225/55R16 is an exact match (obviously due to the different rim size)

 

Smaller tires have more revs per mile and vice versa for the larger tire. So if you choose the 205/55R16 then your odo will show more miles then you actually travel. Whereas if you choose the 225/55R16 then your odo will show less miles than you actually cover. I am assuming that the ECU counts the number of revs the wheels make and then calculates the miles travelled using the rev/mile number of the OEM tire for which it is calibrated.

 

My guess is that the salesman must have recommended the larger tire since you will register lower miles on your odo then what the actual miles will be.

 

As per my approximate calculations:

• if you choose the 205/55R16 tire then your odo will show 8 miles extra for every 1000 miles you cover

• if you choose the 225/55R16 then your odo will show 26 miles less for every 1000 miles you cover. Thats a lot!!!

So over a course of 10000 miles you have a choice of putting an extra 80 miles on your odo or shaving off 260 miles off your odo!!

Thanks for the write up Topaholic! Makes complete sense to me now. I only plan on running these for at most 4k miles so it should be okay. As long as I know I'm not going to break anything, i'm happy!

In theory, the thinner tire (205) will cut threw snow a little better than the 225. But, the 225 will handle better in dry weather b/c of the bigger contact. I chose a 225/45/17 snow tire, since 80% of winter here is dry. If you bought a decent winter tire, regardless of 205 or 225, you made the safe choice of ditching those re92s this winter.

^^^ What he said: with any winter tire I gotta think you are going to be golden, regardless of what size it is. For me, I'll need to replace my 'winter' rubber (PZero Nero M+S's) in another month or two, and I'm thinking of maybe trying a 215/50-17 size with an actual winter tire this time. I really want a bunch more sidewall for winter, but can't go to 16's with the LGT brakes, of course. Any concerns going to a 25.5" tall tire from the stock 24.6", besides the obvious taller gearing and odometer readings? Will that tall of a tire fit below the spring perch on my stock struts + iON combo? Will 0.9" size difference kill the differentials if for some reason I have to use the full-size (215/45-17) spare I have?

 

Sorry for the semi-hijack...

Wait, I thought stock tire size is 215/45/17 for the newer legacies as well? The older subbies used 205/55/16 and 215/45/17 as stock tires (both Legacy and Impreza's made before the 05+ Legacy's), I didn't know they changed it for the 2.5i's...

I think for 2006 Subaru upgraded the 2.5i to the 17" wheels, but the 2005 2.5i's had the 16's.

The new 2.5i has 205/50R17.

 

I just put Nokian RSi in that size on my LGT. They look fine, not noticeably narrower than the stock 215/45R17 RE92s.

Not surprising: for some reason the tread width on the stock 215/45R17 RE92's is a lot narrower than a *normal* 215/45R17 tire. Every other brand of tire is wider in that size.

Not surprising: for some reason the tread width on the stock 215/45R17 RE92's is a lot narrower than a *normal* 215/45R17 tire. Every other brand of tire is wider in that size.

 

 

Yeah, there can be large variances in width even with tires rated as having the same width in mm; mostly it's due to the shoulder design.

 

Like Falken Azenis; they may say 215 or whatever, but comparing them to other 215's, it's much more wider due to the more aggressive and prounounced shoulders

http://www.miata.net/garage/tirecalc.html

 

Research before you buy tires. 1 in larger tire diameter is too large!

 

 

Also, Narrower tires are bette that wider tires ONLY in snow and rain (and then, only for hydroplaning). Both on ice, and in the dry, it is better to have a wider tire - for ice, if you have a tire that has decent ice traction, the wider the contact patch the better.

 

Generally speaking, if you HAVE grip, then a wider tire gives you MORE grip, so wider is better. This changes when you are plowing through a material other than air on the road =) like water, snow, and slush.

I don't think one inch taller is too tall. Any taller and you might have issues with clearance but you can see in the picture I posted above that one inch taller than stock (205/45/17) and it really doesn't cause any issues. You certainly do need to do your research though.

 

These WinterForce tires are getting broken in and they are super gippy on the snow and ice. Sears did a really crappy job installing the studs but the tires themselves are just unreal for the money. They are not as nice as my studded nokians but they were half the money and they are certainly a well designed tire. The dry road handling is pretty good but you know you are running snow tires and the road noise is really not bad at all.

I don't think one inch taller is too tall. Any taller and you might have issues with clearance but you can see in the picture I posted above that one inch taller than stock (205/45/17) and it really doesn't cause any issues. You certainly do need to do your research though.

 

These WinterForce tires are getting broken in and they are super gippy on the snow and ice. Sears did a really crappy job installing the studs but the tires themselves are just unreal for the money. They are not as nice as my studded nokians but they were half the money and they are certainly a well designed tire. The dry road handling is pretty good but you know you are running snow tires and the road noise is really not bad at all.

 

 

Umm, mm'kay, if that's what you like. The handling of the GT is not spectacular as it is, going to a significantly taller tire is just going to put you into outback territory.

 

But I suppose most people dont even notice how badly the outback handles either, so good luck with that.

Umm, mm'kay, if that's what you like. The handling of the GT is not spectacular as it is, going to a significantly taller tire is just going to put you into outback territory.

 

But I suppose most people dont even notice how badly the outback handles either, so good luck with that.

 

Remind me to not be anywhere near you when you are "performance driving" in the snow