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Discussion Starter #1
My wife wants to drive her car year-around, mostly commuting. We get some snow here but not a lot. The typical storm drops 1-3" and the roads she uses are almost all plowed and treated, with lots of traffic. So the snow tires are probably overkill, peace of mind if she really has to get somewhere in crazy weather.


The car has 18" wheels that came with the Sport package. I decided to get a set of winter wheels to take the brunt of salt and sand damage. That allowed me to choose 17" wheels and tires, all the same size. My wheels are 17x7.5J. The specs say they have a 45mm offset, not the 42mm of OEM front wheels. I think that's close enough. The tires are four 225/45R17. They are very close to the OEM tire diameter, close enough that I can't tell the difference in diameter.


I chose Goodyear Ultragrip Ice WRT tires because we had them on our Miata and they worked fine on the same commute. I believe in Europe, the same thing is sold as Dunlop Winter 3D. The speed rating is not too high, so if you want to go faster than 112mph, pick another snow tire.


Changing wheels means getting new tire pressure sensors. The car eventually found the new sensors once I reset the system. You may need new lug bolts. I got those as a shortcut to searching for wheels that fit the OEM bolts. My wheels had smaller holes for the center cap than the OEM wheels, so I just left the free cap on.


I changed the wheels myself with the car's tools to get some experience in case I ever have to use them. (I figure I'll be too impatient to wait for roadside assistance.) I would add two items to the car's kit. One is a 17mm deep socket. This is because the wheel's bolt holes are too deep and small to finger-tighten the bolts. A cheap one is fine since you are only using it to hand-tighten. Also get some hand wipes or gloves, so you can get back in the car without leaving brake-dust handprints on everything.


Here is a before and after photo. The looks could be better but I think it's close enough for winter driving.


 

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I would add two items to the car's kit. One is a 17mm deep socket. This is because the wheel's bolt holes are too deep and small to finger-tighten the bolts. A cheap one is fine since you are only using it to hand-tighten. Also get some hand wipes or gloves, so you can get back in the car without leaving brake-dust handprints on everything.
Your car looks great to me... and thanks for the tip about handwipes etc...:smile:

Stella
 

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C Class wheels for SLK 250

I just bought my first Mercedes. An SLK 250 with the 18" tire package. I was searching for winter tires. I found a set of 4 for sale with OEM wheels from a C Class. They are 17 " tires and wheels. They are the exact same tires and size as my manual recommends for winter but the wheel offset is .47 millimeters. My wheels are .42 offset. So there is a 5 millimeters or about 1/4 inch difference in offset. The wheels tire rack recommends are offset .45 so these are only .02 millimeters more. My questions is, does anyone know if they will fit or cause a problem? These tires were manufactured on the 27th week of 2013, so as the seller says they were only used one season and look like new. By my calculations they are about $600.00 less than buying everything including sensors from tire rack.

Any information would be appreciated.
 

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Check the size of the wheel bolts. The wheels from a C Class(from the same time period ), CLK, R171 & R170 are all interchangeable. They will not fit an R172 however, as the wheel bolts are a different diameter.
 

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Discussion Starter #7
I've driven the car in enough different weather conditions to pronounce this a success. My goal was to handle surprise weather, and the tires are even better than that. The Goodyears are not mentioned very often - I see Blizzaks mentioned a lot - but they work fine. I don't know about wear yet.
Here's a photo from one of my tests. Our city doesn't plow neighborhood streets, so the tires have to handle the packed snow. The neighborhood has some hills, not the steepest but a problem for some cars. I could point the car uphill, stop, rev up to 2500 rpm, drop the clutch and go.



The tires are also OK when the packed snow turns to ice. Obviously ice is trouble for anything without studs, but the tires have enough traction on it to get through patches.
I think the tires are noisier than the summer tires, not enough for me to complain. Ride is the same. I feel better about hitting a pothole or rutted ice surfaces with the higher profile. Dry handling suffers a little, less grip I'm sure. Winter driving means allowing for sand or other surprises so I don't corner at the limit anyway. The car feels just a little different when I enter a corner, like a turn-in oversteer. That's just as you turn the wheel off center. I suspect that the cause is either the slight change in offset (from 42mm to 45mm) or the decrease in rear wheel width. I don't think it's the tires because we have the same snows on the Miata without this feeling. I think it's something an attentive driver would notice but not a problem.
The wheels are apparently a Tire Rack house brand, rumored to be made by Kosei. They have a raised rib on the inner rim between the spokes where the stock wheels are mostly flat. This helps conceal the brake dust, which is nice. Keeping the car clean in the winter is the biggest disadvantage to winter driving, and I don't want to spend forever cleaning the wheels.
 

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C Class wheels for SLK 250

This is a follow up to my post from a couple of weeks ago. The seller delivered the tires and wheels to my house. He wanted me to try them out before I bought them. We changed all 4 tires in the garage and I took it for a test drive. I had called my Mercedes dealer the day before and spoke to someone in the service department. He told me the extra few millimeters wouldn't cause a problem. After the test drive we checked out the tires to make sure nothing was rubbing on anything. I had turned the wheels all the way in both directions to make sure everything was ok. After the drive and inspection I was satisfied that everything was ok. I only have a little over 1000 miles on the car with only about 200 miles with the snow tires. The car seems to drive much smoother in the very cold weather. The summer tires seemed to ride very hard.

I did a lot of research before making the decision to have the guy bring the tires over. I even checked out the lug bolts and they were the same size for the winter wheels. The wheels are OEM, not after market. I am very satisfied with the purchase. I am most concerned about driving in very cold temperatures and maybe being caught in a little snow. I don't intend to just go out driving in a heavy snow storm. It is going to snow here in New Jersey today (1"-3") but other than my driveway I don't think they will get much of a test.

Just1MoreDave, if you see this I have a question for you. The wheels on my car were 18" and I bought 17" all the same size. They have sensors but the system won't recognize them. You mentioned after you "reset the system" it recognized the sensors. Every time I go out I do the system reset but it always shows the message, "system not operating" or something to that effect. The Mercedes service man told me that the system wouldn't recognize the different size tires. I am wondering how long it took yours to accept the new tires or did you take it to the dealer for a factory reset?

Thanks to everyone who made a comment here and on a similar post in my introduction.
 

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Discussion Starter #10
I just used the steering wheel controls, Serv. -> Tire Pressure -> Press OK to Restart. Page 318 of the manual. I tried it several times, first driving about the distance typical to display any temperature, then farther, then enough times to be ticked off that it didn't work, then just one more time after about 3 miles/10minutes and it worked. They do still work fine.


I switched from 18" summers to 17" winters just like you, and the winters are the exact spec mentioned in the manual. They do mention that switching to a different tire diameter can confuse the ESP for a while, but I think if you measure, your winter tires are the same diameter at the tread as the summers. At least mine are. The wheel size is smaller but the tire sidewall is thicker, so it works out to be the same. If your tires are 225/45 R17s, they should be fine.


Tire Rack sold me 433 MHz sensors. If you are really unlucky, the C Class used some other sensor type, which sounds unlikely.
 

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Dave,

Thanks for the reply. I did the exact same reset procedure about 4 times and just gave up. After about 10 or more miles I get the disabled message and the tire light on the dashboard stays on all of the time. I have no idea what the MHz of the sensors are. I do have the exact same size tires and wheels as you do. It was your post and reading the manual that helped me decide to get them. My car came with the two different size tires and 18" wheels. After I read your post I did a search on craigslist and there was one listing for tires, wheels and sensors. They just so happened to be the tires listed in the manual. The big hangup I had was he said they were from a C class and the offset was different. I really didn't want to buy 4 wheels, tires and sensors for a car that I am only going to have for 3 years but after doing the research and seeing what they would have cost me on tire rack I decided to get them. I only paid $800.00 for everything and as I mentioned the guy delivered them to my house and let me try them. I couldn't ask for a better deal than that. If I don't get another SLK I can always sell the wheels after I turn in the car.

I will try the reset again the next couple of times I go out and see what happens. I will also see what I can find out about the MHz.
 

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Discussion Starter #12
It looks like 433 MHz is typical for Europe. The sensors also have batteries in them. A tire store might know whether the sensors are still working. It would have to be a place that wasn't simply interested in selling you a whole new set of sensors plus a free air rotation. You'd still be ahead even with new sensors. My invoice says they were $62 each.
 

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Dave,

I really had no idea how they work, but a battery makes sense. He only got the tires and wheels last year so unless inactivity drains the battery they should still be good. I haven't had time to research the sensors but I will over the weekend. I plan to take the tires off by April 1 anyway so if they don't work it isn't a big deal. I went out to my grand daughters basketball game today and drove long enough to get the disabled message again.

I'll let you know if they ever reset.

Thanks for all the info.
 
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