Winter Tire Sizes for '98 with 17" Wheels

Greetings,

Last year I purchased a set of the General Arctic X winter tires for my '98. The fronts are the same size as my summer tires, but the rears are 225/45 and my summer tires are 255/40. I immediately noticed that the rear of the car did not seem as stable as with the summer tires; the car seemed to "sway" as I would turn the steering wheel at speed. There are no winter tires available in 255/40 17's that I can find so perhaps there is a good reason for that, however I feel that the 225/45's might be too narrow and too tall for the rear, thus the swaying feeling.

When my summer tires went back on earlier this year the difference was quite noticeable and I was glad to have my "real" Boxster back!

Below are some winter tires of the same brand and model from Tirerack, including my current 225/45's at the top. I am looking to only replace the rear set, so can anyone with experience with this comment on the other sizes and if they might feel more stable than what I have?


225/45R17 91Q $124.00 (ea.)
225/55R17 97Q $127.00 (ea.)
235/45R17 94Q $137.00 (ea.)
235/55R17 99Q $136.00 (ea.)
235/65R17 108Q $128.00 (ea.)
245/65R17 107Q $139.00 (ea.)
245/70R17 110Q $131.00 (ea.)
265/65R17 112Q $152.00 (ea.)
265/70R17 115Q $138.00 (ea.)

Any wisdom is greatly appreciated!

Sebastian

2001-2 Boxster S models often came with 225/45-17 as their stock rear size. If you do the math its nearly identical in OD.

Yes, its higher aspect ratio so less stuff. No surprise there. Its also a snow tire, ergo same thing. Finally, it's now 30mm less stagger, which reduces under-steer (good or bad depending....)

For the record, my winter tires are on 16" rims 225/50-16 rear; 195/55-16 front. So i'm on bicycle tires compared to you.

Actually, its quite fun. Big slip angles and excitement at low speeds!

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Thanks Grant,

I appreciate the info. One last question: If I were to find a winter tire in a 255/40 size, I imagine the car would feel more stable like the summer tires that size. Is it a big no-no to have different brands front to rear?

Thanks,

Sebastian

1. they are the same kind - e.g.; high performance winter
2. you understand that they WILL have different break-away characteristics. Might make it more stable, might make it less. But it will be different. All in all, big whoop - so does a little dirt ont he road.

As noted, i run far more of a balloon winter tire than those and it feels fine. Some snow tires are very soft - e.g.: Michelin Pilot Alpin winters.. while others are quite high performance and stiffer sidewalled e.g.: Dunlop Wintersport M3/3D or Pirelli whatever they call their high end one now.

To calculate outer diameter, you need to know what those sizes mean. 255 is the width in mm. 40 is the sidewall height, as a % of the width. This means 255 x 40%. 17 is the wheel diameter (not radius) in inches. So you need to convert the mm to inches and add the wheel to 2(sidewall height).

shoot me an email for a spreadsheet that does this for you/

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

The approved sizes are in the FAQ:

[www.986faq.com]

I recommend going with the narrowest size that is recommended for your diameter. You will get much better traction in the snow that way.

Grant, thank you for the info on all of this.

Boxsterra, I hear you about traction and narrow tires, but I would give up a little bit of traction to get rid of the unstable feeling of the narrower rear tire.

I did not slip much at all last year, but boy was it squirrely to drive and I attribute that to the narrower width of the rear tires.

I did find a 255/40r17 winter tire today and I think I'll try them, thanks to all for the input; I'll report back once they are mounted.

Sebastian

Snow tires use a much softer compound than summer tires. Some of them are downright awful on a Boxster. The factory approved sizes are perfectly stable as long as you get the right tires and unstable no matter what size wrong tires you put on them.

Grant

gee-lenahan-at-gee-mail-dot-com

Thanks Boxsterra, I will hold off on buying these. Do you have any guidance on what would be the "right" tire vs a "wrong" tire.

At the very least I still have a set of one-season old tires that had good traction regardless of the feeling at the rear.

Sebastian



Edited 1 time(s). Last edit at 11/27/2011 04:26PM by SPG356. (view changes)

But i'd also suggest you find a really good, relatively local tire dealer who can help with these sorts of things. We all want a low price, but i find that seriously good shops are very valuable. Locally, here in NJ, i use Euro-tire (for example both owners are PCA members and racers).

I am not up on the current Pirelli numbering - back when i had a set it was the Winter 210. You can generally assume that as the speed rating in any on brand goes up from T to S to H to V to whatever (W, Y and Z but i've never seen such for winters) the sidewall will become stiffer, and the compound even softer.

I have winter-sports on both my Audi and my Boxster. I like them. I may try Vreidstein snowtracs, partly on Euro-tire's recommendation.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Grant,

I went ahead and installed my original set of winter tires just to see if they were as "bad" as I remembered.

It snowed today and they worked great, the wiggly feeling is much slighter than I remember, and probably due to the sipes in the tread more than anything.

Maybe I was just itching to spend some money, but you guys saved me quite a bundle as I will just stick with what I've got for another few years!

Lunch is on me next time you ride thru Ann Arbor

Grant

gee-lenahan-at-gee-mail-dot-com

I have Hankook Icebears in 17" 255/40 size in the rears. I just threw my winter 17's on last weekend in prep for the cold winter...Have had em for 2 snow seasons, and they work great.
Got em from Discount Tire, as TireRack didn't have em.





Edited 1 time(s). Last edit at 11/26/2011 05:10PM by boxtaboy. (view changes)

This is probably the last season for the 16" Blizzak, but can't seem to find anyone the sell 16" snow tires for the Boxsters for the past two years.
Anyone with good experiences with another brand in that size?