Here's a list of the overall diameters of the various sizes of tires used on the 850:

 195/60/15 = 61.50cm
 205/50/16 = 61.14cm
 205/45/17 = 61.63cm
 215/40/17 = 60.38cm
 215/45/17 = 62.53cm

 And here is a list of the approximate circumferences of the tires, or the distance covered with one revolution: (incorrect: see post below this one)

 195/60/15 = 386.4158964cm
 205/50/16 = 384.1539497cm
 205/45/17 = 387.2327105cm
 215/40/17 = 379.9378728cm
 215/45/17 = 392.8875773cm

 From what I have gathered on this board, all of these tires fit regarding rubbing except for the 214/45/17. It seems one or two people get away with this
 tire, but in general, at full lock, it rubs.

 As for differences in circumference, what is considered an acceptable difference? And compared to which circumference?

 When you think about it, the stock non-turbo and GLT low pressure turbo, as well as recommended snow/winter tire sizes for the base, GLT, Turbo, T5-R
 and R, is 195/60/15. And the Turbo, as well as some T5-R's and R's came with 205/50/16. And lastly, the some T5-R's and R's came with 205/45/17.

 If you compare the three, there is more than a 3cm discrepancy between the smallest and the largest.

 So what circumference do I use as a reference point in determining acceptable difference in circumference? And once again, what is considered an
 acceptable difference?

 I accidentally multiplied the circumferences by two. I didn't realise I did until I thought about just how long just under 400cm is.

 Let's try that again, and I'll reword the part about the differences in circumference:

 195/60/15 = 193.2079482cm
 205/50/16 = 192.0769748cm
 205/45/17 = 193.6163552cm
 215/40/17 = 198.6893644cm
 215/45/17 = 196.4437886cm

 As for differences in circumference, what is considered an acceptable difference? And compared to which circumference?

 When you think about it, the stock non-turbo and GLT low pressure turbo, as well as recommended snow/winter tire sizes for the base, GLT, Turbo, T5-R
 and R, is 195/60/15. And the Turbo, as well as some T5-R's and R's came with 205/50/16. And lastly, the some T5-R's and R's came with 205/45/17.

 If you compare the three, there is now an approximate 1.5393804cm discrepancy between the smallest and the largest.

 So what circumference do I use as a reference point in determining acceptable difference in circumference? And once again, what is considered an
 acceptable difference?

 OK, you did the calculations but what exactly is your question? If you're thinking of getting new tires then the answer is pretty simple--just stick to the
 stock sizes and you'll be fine. If you want a baseline or reference point, I think you should use the tire size that came with that particular car in question as
 your reference point. Like you said, the 850 lineup has a few sets of tires as OE but I think the real question is whether or not Volvo actually bothers to
 re-calibrate the speedos and tachs based on these different tire sizes they use as OE. You understand what I'm getting at?

 Here's my own experience: My car came with 205/50/16s and I've been running with 215/40/17s for about 4 years. This size is smaller than the OE size
 BUT with the rims that I had on the car and Eibach lowering springs (about 1 to 1.25" drop), even these tires rubbed during hard cornering. I recently
 snatched up a second hand set of Volvo-factory winter steel rims with all-seasons (sized 185/65/15) and these rub a little under hard cornering as well.
 So there you go, this is my experience and I'll let you know, there isn't a lot of room for negotiation concerning tire sizes on the 850, IF you lower the car.
 My next logical step would be to dial in more negative camber (to -1 degree) in the front and hope this will cure the rubbing problem I'm having.

 "the 850 lineup has a few sets of tires as OE but I think the real question is whether or not Volvo actually bothers to re-calibrate the speedos and tachs
 based on these different tire sizes they use as OE."

 That's exactly my point. What circumference tire are the tach/odo/speedo calibrated for? It couldn't possibly be calibrated exactly for all three OE sizes. In
 fact, it may even be calibrated for something in between the lowest and the highest while not being either of the three. If I knew the exact circumference it
 was calibrated for, and I could find out the tolerance, I could then make better calculations as to what is acceptable.

 I also thought about the -1 degree of camber helping with rubbing, but when you think about it, it probably won't. It won't because it isn't the outer corner
 of the tire (corner being the point where the sidewall and the tread meet). It is actually the tread that rubs. So -1 degree of camber won't make any
 noticeable difference.

 BTW, how are you going to get the -1 degree of camber? I found some camber plates on carparts.com, that should work on the front wheels of the 850,
 for about $27US. But I'm not planning on doing any suspension work this year besides the strut tower brace. This year, all the available car money is
 going towards power increases, the strut tower brace and the stainless steel brake lines. The suspension will be worked on next year. I may just go with
 the Koni's, set them on the stiffest setting with the iPd springs or go with the Bilsteins with iPd springs, as these two combinations should give me the
 .5-1" drop I'm looking for. I'm not so much looking for lowering as I am for stiffening up the suspension. With the 17" rims I will be running after I wear
 through my 205/50/16 Toyo Proxes T1-S's, I will more then likely be running 205/45/17 tires. And I don't want to lower the car enough to cause rubbing,
 so I hope the 1" max drop I want won't rub.

 Well, I tell you what, it's gonna be a tough job to find those factory calibrations for the speedo, tach, etc. Probably near impossible unless you or
 someone you know works as a tech at Volvo. And I don't mean your average service advisor or parts dept. guy either. I see your point though, and Volvo
 may have them calibrated for all OE tire sizes or only 1 or 2--anything is possible. Personally, I don't find it to be that big a problem not knowing the little
 variation in circumference between my stock tires and my 17" tires because there will be variation no matter what you do. Remember, as the life of the
 tires you currently have on your car wear out, the circumference will decrease as well so it's all moot and really just a numbers game. Out on the road,
 there won't be much discernible difference in the way the car behaves as a result of these variations.

 Regarding the rubbing problem, on both sets of tires that I've tried, the rubbing does happen right at the outer corner (where the tread and sidewall
 meet) of the tire. Maybe you misunderstood by what I meant in terms of "rubbing" in my initial post. I don't have any problems with the inner fender
 rubbing at full steering lock, I just have rubbing happening at the outside lip of the front fenders under hard cornering. A Volvo mechanic told me that
 dialing in -1 degree in the front is actually no problem if done right (no camber plates needed) so go figure. He may be misinformed but if that doesn't
 work, then I have no choice but to get some camber plates--$27 sounds like a good price actually. I'll see how it goes.

 By the way, forgot to mention that if and when you get new rims, pay close attention to the offset--this could ultimately affect whether or not you end up
 with rubbing problems as well.

 I'm pretty sure unless you bend something the camber on the 850 can only vary between -.5 to +.5 degrees. I've heard this from everyone that has
 modified 850's. But it is a possibility that it is simply a passed on myth.

 The biggest reason I want to figure all this out is because when I switch to the 17" rims, I want to either run the OE size of 205/45/17 or 215/45/17. I know
 that even if I don't lower the car I will probably have rubbing problems with the 215. But all the available tires in 205/45/17, that I know of, I don't want. The
 P-Zero Assimetrico is probably one of the most hated tires of 17" rim owners because of side wall weakness. The Yoko A520 wears horribly and is noisy,
 and these problems are only accentuated on a heavy car like the 850. The Yoko Parada seems to be slightly better then the A520, but owners that have
 pushed the tires have reported poor wear characteristics. That leaves the Kuhmo Ecsta. From it's design and materials, it should be a pretty decent tire.
 And in fact, many owners rave about it. And being less then $100US, it's a steal. I just don't want to get a tire that doesn't have a reputation for quality,
 even if it is dirt cheap.

 So unless Kuhmo proves itself in the next year or so, I'll probably get the Parada, which I really don't want to put on my car.

 However, if I put on 215/45/17 tires, there are WAY more to choose from. This goes also for the 215/40/17. And I don't want to go with the 215/40/17
 because I don't want to change the gearing towards higher revs. I do a lot of highway driving, and this will definitely add to gas costs, and even tire wear
 due to a higher number of revolutions. And because I should be in the 295hp and 300ft.-lbs range in a couple weeks, I want to have lower revs. I will be
 increasing the torque so much over stock that I won't need to have the car hit the same rpms for the same speed.

 So basically, the 850 *ucks you over when it comes to upgrading rims and tires. I either stay with the recommended OE sizes and use tires I don't want, or
 I use tires I do want and have rubbing, or tires that change the gearing towards more revolutions per mile.

 Yup, just as I have found--you're screwed if you do and you're screwed if you don't! I'm unsure of the camber thing as well and even the owner's manual
 states that it's + or - 0.5 degree but I'll get to the bottom of this soon.

 To be safe, I'd stay away from the 215/45/17s--you don't want to spend big bucks on a new set of tires and have them rub and wear out funny. Your best
 option is probably the stock 205/45/17--that's probably what I'll be going with when I get new tires this summer. Funny, I've narrowed down my two tire
 options to either the Yoko Paradas and Kumho Ecstas as well. You really can't go wrong with the Kumhos considering the price (how much have you
 found them for? about $95 US is the best I've found so far) But I hear they wear out fast as well (treadwear rating of 220 so I guess that's why)--but I've
 heard great things about them in terms of dry and wet weather performance. The Paradas cost a bit more but they're from a proven manufacturer,
 so...but the Kumhos are just so damn cheap....

 I totally agree with you on the tire choices.

 I think I saw the Kuhmos for about $95US as well (no mounting or balancing or old tire disposal charge included in this price). I'm sure if I go to my tire
 guy, he can get me a better price. For example, the Michelin Pilot sport is found in most places for about $315-$330CAN (all prices included, i.e. 15% tax,
 balancing, mounting, old tire disposal charge etc.), he could sell them to me for $285CAN all prices included.

 Most places that had the Toyo Proxes T1-S had them for about $250-$280CAN all prices included. He sold them to me for $215CAN all prices included.

 I think I'm going to eventually go with the Kuhmo's in 205/45/17 as well. My buddy who is an engineer likes them from their design, and he has worked on
 race cars, so he can't be that wrong. And the fact that they are dirt cheap makes it just too inviting.

 I'm just not going for the Yoko's because of their wear characteristics, especially on heavier cars.

 But, I've got another year and a half to two years before I need to get the 17" tires.

 Yeah, $95 US does not include all those extra charges you mentioned. There's no need for you to decide now though seeing that you won't need them
 for another year and a half to two years. Maybe by then Kumho will have established themselves in the US market and have correspondingly raised their
 prices! You never know, plus the tire market changes so drastically, so fast, who knows what choices you'll have then...

 I know I have time, but I don't expect many new tires in that size to come out anytime soon. And if they do, they'll be directed more towards import (rice
 cooker) racing due to the relative narrow width with the low profile. Which causes problems such as insufficient side wall strength.

 Heck, I'd buy the Kuhmo's right now if I was going to put them on my car. But since I'm not the only driver, I don't get all the say. I got the say on the
 Toyo's only because they were expensive enough NOT to warrant suspicion from my dad. My dad has always been a Michelin man, and loves the high
 performance, yet respectable isolation of the Pilot MXM and the new Sport, and doesn't mind paying for it. I on the other hand, would rather see the
 money go elsewhere, and not necessarily directed towards the car either.

 I second that! Michelins have always been expensive, but dang! For the price of one Pilot Sport, you can have 2 Kumhos! I can't justify throwing that
 much money on a set of tires, regardless of whether or not I can actually afford to, just my opinion.

 Which tire shop are you go to get that damn good price, is it in Toronto area?

 TWO!, Try almost THREE!

 $78 for the Kuhmos and $190 on special for the Mich's at Tirerack.com

 Regular price, for the Mich's was around $215 just a couple weeks ago.

 Hey! What's goin' on Angus?! Man, I just saw you a couple hours ago.

 I don't even know I'm on paying attention to all these posts with a psych exam in 7.5 hours. Damn MSN Messenger for alerting me!!! I can't resist.

 It's a small tire shop called Hi-Standard Tire and Auto.

 Hi-Standard Tire & Auto
 471 Garyray Dr, Toronto
 (416) 740-5029

 I think it is east off of Weston Rd. if my memory serves me correctly.

 It's easy to miss because the sign actually says OK Tire or something like that.

 The owner of the shop is incredible with alignments and tuning. Give him the specs you want, and if you suspension will do it, so will he, and for no more
 cost then that of an alignment. This is the guy that makes it possible for me to run -.5 degrees camber.

 Tell him the guy with the beige Volvo 850 Turbo wagon that bought the Toyo Proxes T1-S tires last summer sent you. I'm sure he remembers me. After
 taking my car for a test drive, to test the alignment, he came back in with this huge smile, and said nothing but, "That's a FAST car."

 He was the PAID onset specialist for the upcoming movie Driven (starring Stallone and Gershon) which was filmed in down town Toronto.

 All because of his years of racing experience. This guy used to be an incredible race car driver/mechanic/tuner and his trophies and awards etc, and
 most importantly, his work, all reflect this. Why do you think he was hired to advise on such a big $ movie?

 One thing though, get the tape weights from him for an extra $5/tire (CAN) instead of the regular weights. He uses cruddy looking weights, while using
 brand new tape weights.

 FYI,

 depending on year, some Turbos, T5s and Rs came with 205/55/16. XCs come with 205/65/15. And not that it makes much difference but I think for 99+
 Rs, the snows have to be 205/55/16 because of oversized front rotors won't fit 15" rims (although I'm not 100% sure of that)

 Mike

 My father just installed 225/45/16's on his '94 850 turbo with no rubbing.

 -Michael

 Angus wrote:

 > Which tire shop are you go to get that damn good price, is it in
 > Toronto area?

 Hey Angus,

 If you're willing to drive a little, may I recommend the Crown Auto Emporium in Guelph? He will beat ANYBODY'S prices guaranteed. Talk to Mike Adams.

 http://www.car-fanatic.com/

 As you may notice, he's also a huge Viper fan. I think he has TWO now.