Thread: Low profile snow tire question

I have a car the has the following tires on them:
Front: 235 40R18
Rear: 275 35R18.

Do I need to mimic these #s for snow tires, or will say 245 40R18 snows fit on the front and back?
Thanks
Auto JONG

Besides a different tread and rubber compound to handle snow/ice, snow tires should also be thinner/taller to "slice" through snow better. You already have very wide rims, so I would try and put the skinniest tire on them that will fit. If I recall from you previous thread, this is for your new 550? You're probably best off just investing in an entirely new set of winter wheels. In my opinion this is a much better option- you can change them yourself and not have to rely on going to a shop at $100 a pop twice a year. Plus, you can get the right size tire- something like a 225/50/16-17. I know it will look like crap compared to your 18's but it will handle the snow much better. I used to have a carrera with summer 19's and it always felt like I was transforming it into a fiat when I put my winter 17's on, but that is in CH where having winter wheels is the law.

Puder Luder

Check out the Tire Size Calculator and compare the size of the stock tires to the size you want to run. As long as the circumference is within a few percent you should be good to go. So, switching width is no big deal but switching height can be a problem.

If you don't want to have your speedometer corrected/recalibrated, you are going to have to find tires with the same circumference as what you currently have. If you are willing to buy a second set of rims, there is no reason they even have to remain 18's or have the same width as what you are currently running.

IMO, 35/40 aspect ratio (height of the sidewall as a percentage of tread width) is abnormally low for a snow tire. With the rear almost an 1 1/2" wider than the front, I'm guessing a Porsche, and the extra width in back helps compensate for the extra weight in back.

I didn't spend much time digging, but if you go to Tirerack.com, you can pull up the specs for what you are currently running. I found 819 revs/mile listed for 235/40-18, and a 245/45-17 matches that. You will be fine with anything in the 800-840 revs/mile range, as that is only +/- 2.5% of what is currently on there.

You might even check what is available in 16" diameter too. The higher sidewall will make for a little mushier handling in the dry, but save expensive rims on terrible winter roads. Going a bit narrower is also going to give you better winter/snow traction, at the expense of dry handling.

If you have the space to store them, I would go with something like the following: 225/45-17 front,245/40-17 rear, mounted on a second set of rims.
Tirerack shows those sizes are available in a Blizzak LM-25

One other thing to consider is that the 18's very well may be required to clear the brake calipers on a high performance car - 16" or 17" wheels may not fit. Check with TireRack.com by selecting your exact vehicle, which will allow you to view the most appropriate winter tires and / or tire and wheel packages. They are also very helpful on the phone if you have specific questions.

+1 on the separate set of wheels for your winter tires. I do this on my 330xi, and it saves you the hassle and cash associated with paying a tire shop to mount and re-balance 4 tires twice a year.

Also +1 on narrower tires for winter - they cut through the snow a lot better. Wide tires float and slide around more.

+2 on seperate wheels. I loved being able to swap mine out in the garage on snow days. I have a compressor and a decent jack. It took me less than 20 minutes to do the switch and saved a ton of wear on my snows. They rarely hit dry pavement and after 2 seasons of use still look nearly new.

Good stuff here, thanks. Tire Rack is recommending 245 40R18.
I can get blizzaks in this size for $225 installed. The other option is 4 17" rims, and then 225 50R17.

I guess that I'll also have to buy chains. Do I go with 2 or 4 chains to get up LCC?

Originally Posted by schindlerpiste

Good stuff here, thanks. Tire Rack is recommending 245 40R18.
I can get blizzaks in this size for $225 installed. The other option is 4 17" rims, and then 225 50R17.

I guess that I'll also have to buy chains. Do I go with 2 or 4 chains to get up LCC?

Ah, that's what you get for buying the 550, rwd right? My carrera was horrible in icy conditions- all the weight of the engine over the rwd. I never used chains though, but this was CH where the roads are perfectly maintained.

I'd only put chains on your rear. But with really good snow wheels you'd probably never need them.

Puder Luder

Tire Rack is right.

When you have large High Performance tires you need the same in a snow tread.

Blizzaks or Pirelli Scorpion Ice and Snows and you'll be fine.

Lets face it, if you need more tire than that you won't be going anywhere with the ground clearance of a 550i anyway.

Hell, if you can afford a Carrera why not buy a second car that actually works on snow. Or wouldn't you be seen dead in something as uncool as a secondhand compact?

Originally Posted by amatog

Tire Rack is right.

When you have large High Performance tires you need the same in a snow tread.

That isn't true. When you have staggered summer wheels and tires, you really want to go with 4 wheels and tires that are the same for your snows. I would go with something like a 235/45/17 mounted on a second set of rims. Make sure the rims will clear your brakes. With snows on they likely will not make you chain up. But if they do, just the rear drive wheels is needed.

-1 on second set of rims. Around here it costs about $65-$70 to have tires mounted and balanced. For my vehicle you are looking at $140 minimum for a set of four rims (assuming I don't have a full sized spare in the rotation, which by the way, I do).

So you buy those 4 rims for $560 (that's CHEAP frikin rims). I have to pay for one mount and balance to get those snows on. So now I've got $640. $130 per year to do it without rims. That means you have to go 5 years to break even. FIVE YEARS TO START REALIZING SAVINGS!

Except it's even worse because your tires will wear out before then which means you end up investing more in remounting both your all seasons and your winters as you buy new ones at least once in that period depending how long lived your tires are and how much you drive. You are probably looking at 7+ years to recoupe your costs. Now, maybe that works for me who had his last vehicle for 11 years, but then you have to look at marginal costs of having that money tied up in rims instead of doing something else for you (for example invested earning interest).

Further, if you have a modern vehicle with TPMS, your new rims will not and your TPMS light will forever be blinking unless you drop another $100-$200 per rim to add TPMS sensors.

And that's all before you consider the time and effort of jacking your car up and changing your tires by hand.

Originally Posted by nickinbc

Hell, if you can afford a Carrera why not buy a second car that actually works on snow. Or wouldn't you be seen dead in something as uncool as a secondhand compact?

I had a 911 TT and that car was a blast to drive in the snow as it was AWD with about 475 hp after a stage 1 upgrade. Fuck I miss that car.

Originally Posted by Summit

-1 on second set of rims. So you buy those 4 rims for $560. I have to pay for one mount and balance to get those snows on. So now I've got $640. $130 per year to do it without rims. That means you have to go 5 years to break even. FIVE YEARS TO START REALIZING SAVINGS!.

Summit, if you drive a nice car, $2,000 for snows and wheels is a drop in the bucket. We are not talking a Honda here.

Originally Posted by liv2ski

Summit, if you drive a nice car, $2,000 for snows and wheels is a drop in the bucket. We are not talking a Honda here.

Staggerwing and Crank54 were talking about getting new rims for the idea of saving money. I am saying that is wrong. I made the conclusion with my Honda. I made that same conclusion with my new Toyota. Actually it would have made financial sense for the Honda if done early in its life as it's little rims are cheaper. The more expensive your car with more expensive rims, the less financial sense it makes to buy new wheels. The more sense it makes to buy your tires and have the shop swap them out on the same rims.

If you have your own air tools and lift and do it for cosmetics and the fun of it like Cruiser, well I can't argue with that!

Originally Posted by Summit

-1 on second set of rims. Around here it costs about $65-$70 to have tires mounted and balanced. For my vehicle you are looking at $140 minimum for a set of four rims (assuming I don't have a full sized spare in the rotation, which by the way, I do).

So you buy those 4 rims for $560 (that's CHEAP frikin rims). I have to pay for one mount and balance to get those snows on. So now I've got $640. $130 per year to do it without rims. That means you have to go 5 years to break even. FIVE YEARS TO START REALIZING SAVINGS!

Except it's even worse because your tires will wear out before then which means you end up investing more in remounting both your all seasons and your winters as you buy new ones at least once in that period depending how long lived your tires are and how much you drive. You are probably looking at 7+ years to recoupe your costs. Now, maybe that works for me who had his last vehicle for 11 years, but then you have to look at marginal costs of having that money tied up in rims instead of doing something else for you (for example invested earning interest).

Further, if you have a modern vehicle with TPMS, your new rims will not and your TPMS light will forever be blinking unless you drop another $100-$200 per rim to add TPMS sensors.

And that's all before you consider the time and effort of jacking your car up and changing your tires by hand.

For the most part I agree with this, but you also should consider that downsizing the diameter of the wheels by an inch for the snows will save quite a bit on the tires themselves.

edit: just some tire rack prices for example

blizzak ws-60
18": $166/tire
17": $142

michelin pilot alpin pa3
18": $223
17": $178

Just saying that one of the primary reasons to go with a secondary set of wheels is to be able to go down a size and save a good chunk of cash on the tires. This makes the breakeven point quite a bit sooner.

Originally Posted by schindlerpiste

Good stuff here, thanks. Tire Rack is recommending 245 40R18.
I can get blizzaks in this size for $225 installed. The other option is 4 17" rims, and then 225 50R17.

I guess that I'll also have to buy chains. Do I go with 2 or 4 chains to get up LCC?

For a RWD car? 4, absolutely. You need two in the back for acceleration and two in the front when you turn. Don't know what they require, but when it's nasty you'll at least want the option of putting four on. You won't need four all the time but believe me, some days you will really need four.

(Just pull far away from the road to put them on, people will be itching to spray a guy in a Porsche trying to get up the canyon.)

Summit, you can sell the rims when you are done, so it's not exactly throwing money away. The convenience is nice too, especially after the first snow of the year and it's a long wait at every tire place.

Originally Posted by liv2ski

I had a 911 TT and that car was a blast to drive in the snow as it was AWD with about 475 hp after a stage 1 upgrade. Fuck I miss that car.

ok, so where was this car good in the snow?

hooking up from the line on shiny snow?
fantastic braking on black ice?
high G cornering and full drifts on glare?
owning the hammer lane in a blizzard on i-70?
blazing through 18" of fresh?
turnin those horses loose on a twisty snowy downgrades before the salt shaker comes through?

I'm just trying to find some other rims for my jeep so I can drive it on railroad tracks.
That might sound weird, but it's a hoot.

Shindler, I found the perfect set of winter tire/rims for you. I would've bought them but they wont fit my 5 series because it's all wheel drive. PM sent.

A few random thoughts;
1. Separate rims is a great way to go but stick to the same rim diameter because of brake caliper issues.

2. 4 snow tires is better than 2.

3. If you're swapping tires on rims then the rim width matters since a given tire only fits a narrow rim width range. (The stock wheel size is on the driver's door jamb.)

4. My local tire shop has free tire rotation for their customers so swapping/rotating my summer/winters tires (on rims) is free anyway.

5. Cars with tire pressure monitors are a PITA because the transmitter IDs can only be programmed by the dealer so swapping rims can be costly.

5. Cars with tire pressure monitors are a PITA because the transmitter IDs can only be programmed by the dealer so swapping rims can be costly.

Not true all the time. I run two sets of rims/tires on my GMC. They both have TPM's on them and I can reset them myself. Other brands may differ.

Originally Posted by highangle

ok, so where was this car good in the snow?

hooking up from the line on shiny snow?
fantastic braking on black ice?
high G cornering and full drifts on glare?
owning the hammer lane in a blizzard on i-70?
blazing through 18" of fresh?
turnin those horses loose on a twisty snowy downgrades before the salt shaker comes through?

More like in big empty parking lots with a few inches of fresh over packed for some fun doughnuts. Guys drive their TTs all the time in winter with snows on them. The conditions you listed above suck for most any car. However, with snows on it or good AS tires on minimal snow and hopefully little ice (I am assuming the road has been plowed) the AWD TT is a very enjoyable car to drive safely in winter conditions. It is not a replacement for a 4X4 truck if you want to get your self away from plowed areas.
But back to the OP issue, I would still suggest 17 inch wheels with snows mounted on them for winter use. You can trade them and your normal tire on and off in your garage in about 30 minutes and be much safer when driving in snowy conditions. You save money on your normal tires, as the are not always on the car, wearing out faster and eventually when you sell the car, you likely get half of the cost back for the second set of tires and wheels. But saving money isn't the point. The convenience of two sets of tires and the safety of snows on a rear wheel drive car is IMO.

Wow, this turned out to be a really informative thread. Everyone, thanks for the input.
Deep, thanks for the hook-up.

Splat, you're a nut!

+however many for snows on seperate set of rims 1 size down (17") square set up (all same size) on rwd BMW.

Staggered set up (what you're running now) is designed to prevent oversteer on dry pavement in high performance driving. Snows are too squirmy for real high performance driving so that's a non factor. Smaller and Narrow bites and clears snow better. Chains? Ground clearance will proly be a factor before traction is if snow is deep enough for chains.