Tire Size Spec Topic is solved

[prwood]

Regarding my 2001 V70. I have a lot of assumptions about this car, so perhaps we can confirm or deny them.

The tires currently installed are 205/55R16. I had this set installed in 5/2016 to replace the set that was on the car when we purchased it in 10/2015, which had worn down. I actually don't remember the size of the old tires. I purchased this size based on Sears's online tire configurator which listed 205-55-16 as "standard", and size 215-55-16 as "option 1".

I've always looked at the fuel door to get the inflation pressure spec, but it wasn't until just yesterday when I filled up that I noticed a tire size spec printed there:

It lists 195/65R15 as the size next to the "Optional Pressure" line. Does this mean that size goes together with the lower pressure? Or is that the size we're supposed to have installed regardless of pressure? I always assumed the lower pressure just meant that you could lower the pressure if you were carrying a lighter load, but didn't connect it with tire size. If I've been running with the wrong size tire for the past year, I'd like to know.

I also visited https://www.volvotireadvantage.com/ which I'm assuming is authoritative, and it's saying 205/55R16 is the correct size for this model.

195 vs 205 is the width in mm
65 vs 55 is the sidewall's height as % of width (equal to 126.75mm vs 112.75mm)
15 vs 16 is the wheel diameter

So the spec of the tires actually installed on the car, which is also the same listed with Sears and Volvo, has a wider width, a shorter sidewall, and a larger diameter, than the spec on the fuel door of my car. If the fuel door spec is what I'm supposed to be using, then what would be the effect of the tires I *am* using? If I can just ignore the fuel door spec, then I'll just ignore it...

[Georgeandkira]

195-65-15 was the size on my 1999 base V70, a P1
195-65-15 was the size on my 2002 base V70, a P2
205-55-16 is the size on my 2007 base V70, a P2
If you do the math you'll see there's negligible difference between the height (therefor circumference) of these two tire sizes.
The 205 is 0.4" wider than the 195. You can ignore any difference.
I imagine the 205 will have a speck (as in crumb, teeny-weeny bit, unmeasurable amount) more traction.
I prefer the 65 series tire because it'll save the wheels better given our roads less-than-perfect condition.
If TPMS sensors would fit in my '02's 15" wheels (Lysithia), I'd gladly trade my '07's 16" Echos for them.

Overall sidewall height, ride comfort and perceived coolness are all that's involved here. Kira

[prwood]

Based on this, would this explanation make sense?

1. 195-65-15 was printed on the fuel door flap because that was the spec when the car was assembled in 2001.
2. Some time between 2001 and 2007, Volvo updated their tire fitment specs for P2 chassis (assumedly syndicated out to tire wholesalers, sears, etc) to call for 205-55-16.
3. The 195-65-15 tire size was specified in tandem with the suspension, steerings, and body measurements of the vehicle as manufactured in 2001, but since the P2 didn't change much between 2001-2007, the newer spec'd tires should be expected to fit the same. That being said:

* Does the wheel size indicated on the tire (16" vs 15") have to match the actual size of the rim? Because my assumption was that if the car was originally spec'd to have 15" tires, then the rims would also have been 15", and putting 16" tires on would not be a proper fit. Clearly they do fit, otherwise Sears wouldn't have put them on and they would have come off by now, but I have a nagging instinct to try and honor the engineers' original design wherever possible.

[Georgeandkira]

You are either pulling our collective leg or simply over thinking this.
The "only" thing that HAS to fit is the diameter, bolt pattern, offset and be within acceptable OVERALL volume.
The wheel you have is 16". Only a 16" tire can be mounted on it.
The bolt pattern is the size of the pentagon formed by the 5 lug holes.
The offset is the amount, a length, the tires center is inboard or outboard of the mounting surface.
As far as overall volume goes: You could get a 195-80-16 tire and the 16" diameter would allow mounting on your stock wheel.
The high aspect ratio would prevent you from getting it into the wheel well.

The fuel door sticker is not an encyclopedia. It merely lists an optional tire's suggested pressure. In the case of the 195-65-15 tire option, which you DON'T have, it would be 29psi. The only other data on that sticker is that 38psi is recommended for fuel economy.
Frankly, that the sticker doesn't list the other sizes seems confusing. There might not be any other "acceptable" tire sizes.
There may be a listing of acceptable sizes in the owner's manual, if there are any.

Remember, you can get those stupid, 20" "cocaine dealer" tires in a 195 or 205 width and as long as the aspect ratio is low enough, say 10 or 20, they'll go on your car if the overall volume and shape of the mounted tire fits the wheel well. Like a bicycle tire they'd need higher pressure and guess what,... they aren't listed on your fuel door.

Stick with the 2,3 or 4 stock tire sizes any car might list and you'll be "honoring the engineer's original design".
That "nagging instinct" is a smart one. You'll save time, money, fuel and headaches using the range of tire stated by the manufacturer. Don't freak if a fuel door sticker is a little incomplete.

[prwood]

I'm a programmer by trade, so I am probably overthinking it. Also, wheels and tires is one area where I don't have a lot of experience... so I have lots of questions... and they're not "how do I fix this" questions (not at the moment anyway), they're more "why is the sky blue?" type questions.

I appreciate your willingness to put time into answering my "blue sky" questions.

You are either pulling our collective leg or simply over thinking this.
The "only" thing that HAS to fit is the diameter, bolt pattern, offset and be within acceptable OVERALL volume.
The wheel you have is 16". Only a 16" tire can be mounted on it.
The bolt pattern is the size of the pentagon formed by the 5 lug holes.
The offset is the amount, a length, the tires center is inboard or outboard of the mounting surface.
As far as overall volume goes: You could get a 195-80-16 tire and the 16" diameter would allow mounting on your stock wheel.
The high aspect ratio would prevent you from getting it into the wheel well.

The fuel door sticker is not an encyclopedia. It merely lists an optional tire's suggested pressure. In the case of the 195-65-15 tire option, which you DON'T have, it would be 29psi. The only other data on that sticker is that 38psi is recommended for fuel economy.
Frankly, that the sticker doesn't list the other sizes seems confusing. There might not be any other "acceptable" tire sizes.
There may be a listing of acceptable sizes in the owner's manual, if there are any.

Remember, you can get those stupid, 20" "cocaine dealer" tires in a 195 or 205 width and as long as the aspect ratio is low enough, say 10 or 20, they'll go on your car if the overall volume and shape of the mounted tire fits the wheel well. Like a bicycle tire they'd need higher pressure and guess what,... they aren't listed on your fuel door.

Stick with the 2,3 or 4 stock tire sizes any car might list and you'll be "honoring the engineer's original design".
That "nagging instinct" is a smart one. You'll save time, money, fuel and headaches using the range of tire stated by the manufacturer. Don't freak if a fuel door sticker is a little incomplete.

[850 LPT]

The general rule is that you can put any tire on your car that is within 3% of the original tire diameter, which in your case is the 195/65/15.
I use this handy converter whenever I want to put something other than the original size on my car:

http://www.tireconvert.com/

[JRL]

You can put whatever damn size you want on it as long as it's at least the minimum size, it fits, and it not too tall or too wide, causing tire rub.
If your steering stops are worn or the wrong ones they may rub, it dos not mean the tire is the wrong size!
195/65/15 came on base, non turbo cars up through the 2005 models, a very dinky tire for this vehicle!
205/55/16s is the newer base size and all turbos, is nice, but still too small for my tastes.
235/45/17s are great and the wagon will handle much better but if it's a "wide" tire, (different manufactures make the same "size" tire but can have up to nearly an inch wider tread) it will rub at full lock unless you install R steering stops.
However the wagon then will have a huge turning radius!!

Oh, and with those three sizes above, the speedometer will be VERY close, so don't worry

I run 235/45/17s and love them. Only under FULL steering lock will I rub a hair so I just watch it.

As for the sticker: The optional pressure is for comfort and unloaded. It is for most wheel and tire combinations but you use your head and also what feels best.
Personally I like about 34 lbs for almost all situations and all wheel and tire combinations. If you run 38 lbs. it may rattle to death and be uncomfortable!

If you must, run 36 lbs no more, unloaded.

235/45/17s, my wagon.

[Georgeandkira]

36-38 has been my pressure for years. Always a stock size...I'm not adventurous regarding car parts. I'm thrifty (cheap) too.

[prwood]

235/45/17s are great and the wagon will handle much better but if it's a "wide" tire, (different manufactures make the same "size" tire but can have up to nearly an inch wider tread) it will rub at full lock unless you install R steering stops.
However the wagon then will have a huge turning radius!!

Just to clarify, even though your V70 and my V70 are at opposite ends of the P2 production (2001 vs 2007), any changes in chassis, wheel, or suspension/steering hardware during that time were negligible and would not affect my ability to install 235/45/17s?

[prwood]

The general rule is that you can put any tire on your car that is within 3% of the original tire diameter, which in your case is the 195/65/15.
I use this handy converter whenever I want to put something other than the original size on my car:

http://www.tireconvert.com/

Thanks. I used the Tire Convert website you recommended to verify that both the 205/55/16 (which I'm currently using) and 235/45/17 (which JRL recommended) are within the acceptable range as compared to the original 195/65/15:

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