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Much respect for all of you that take time to answer many questions regarding our beloved cars 😁.
I have a W211 classic 220 CDI, year 2004. Since I bought it (second hand) it had 18 inch alloy wheels (the tyre index is 245/40 R18).
So my question is: is there any problem keeping these 18 inch wheels? Does it affect auto transmission (5G) in any way? Lately I have been having much problems with the tires (all of the tires were cracked all way round from inside, which led me to do a wheel alignement, which was really needed...).
Also something that I have noticed is that when I use cruise control, I set it at 60km/h and it shows 59km/h. Of course also when going through a hill it slows speed a lot until it tries very hard to keep the set speed.
From what I have read, the tire size causes many vibrations to the auto trans, and also can cause issues with the cruise control (until now nothing very worrying).
So what are your thoughts and suggestions. Should i revert to 16" alloy wheels or keep them? Since the manual allows only 16" or 17" wheels, could it damage the car?
I would go back to a 16" rim. The 18" look nice and all but as I understand can't be rotated front to back like 16's & 17's can so uniform tire wear would be much better with smaller rims imho.
I have a W211 classic 220 CDI, year 2004. Since I bought it (second hand) it had 18 inch alloy wheels (the tyre index is 245/40 R18).
So my question is: is there any problem keeping these 18 inch wheels? Does it affect auto transmission (5G) in any way? Lately I have been having much problems with the tires (all of the tires were cracked all way round from inside, which led me to do a wheel alignement, which was really needed...).
Also something that I have noticed is that when I use cruise control, I set it at 60km/h and it shows 59km/h. Of course also when going through a hill it slows speed a lot until it tries very hard to keep the set speed.
From what I have read, the tire size causes many vibrations to the auto trans, and also can cause issues with the cruise control (until now nothing very worrying).
So what are your thoughts and suggestions. Should i revert to 16" alloy wheels or keep them? Since the manual allows only 16" or 17" wheels, could it damage the car?
Don't be stuck on the wheel size alone. It's the combination of the wheel and tyre that make the difference, or doesn't.
Google tyre size calculator, and compare your current size to the ones on the sticker. What number is important on how your car works, is the circumference, which converts to revs per mile, and your 245/40R18 checks out just fine. It's basically same as the stock sizes. So no, doesn't have any affect on transmisson, nor cruise control.
But if they are cracked, an alignement doesn't fix them, you'll need new tires.
And as you have same size on all four corners, you can rotate them for even wear, no issues there.
Only drawback I see is that short sidewall will give you a harsher ride, especially if you compare it to the 205/60R16.
Don't be stuck on the wheel size alone. It's the combination of the wheel and tyre that make the difference, or doesn't.
Google tyre size calculator, and compare your current size to the ones on the sticker. What number is important on how your car works, is the circumference, which converts to revs per mile, and your 245/40R18 checks out just fine. It's basically same as the stock sizes. So no, doesn't have any affect on transmisson, nor cruise control.
But if they are cracked, an alignement doesn't fix them, you'll need new tires.
And as you have same size on all four corners, you can rotate them for even wear, no issues there.
Only drawback I see is that short sidewall will give you a harsher ride, especially if you compare it to the 205/60R16.
Thank you for your reply 🙏.
I went to the tire shop today and he told me that due to the missalignement I had before the back tires were worn at first. Which probably resulted in them being cracked on the inside even after I did the alignement.
In terms of car use, except the cruise control which shows 1km/h less in any mile (the cc engages fine in any speed), the car runs fine. At first the car had some chinese tires which I never heard before. I changed them to a certified european tire maker and the harsh ride and noise from tires was reduced a lot.
Ah also I forgot to mention, all of the front ball joints and two suspension arms were gone. But I do think that it has to do to aging/use or poor manufacturing of these parts (I dont think the tire size loads these parts as much. Most of the roads I have here are good with not many potholes).
For the moment I will stick to these 18" wheels, and later on I will find some 16" and do a test drive just to feel the drive if it has any changes in acceleration or comfort.
You're going to get better fuel economy with narrower tires on smaller rims.
Well to be honest, there is a truth to what you are saying. Also there is a reason in the fuel cap there is a note to the type of tyre you should use. A bigger rim can be good for a bigger engine due to its power. For a 220 cdi engine for sure it would be an overkill. But I do also think that maybe due to this car being a classic model maybe the front suspension and arms are not aligned for a 18" wheel.
I am intrigued to know if someone has had any experience changing from 18" to 16" wheels, and what the driving experience has been. Also an 18" wheel has a larger round diameter, and if the car is designed for 16" or 17" it is probable that it would change the responsivness (from what I read in a forum this was the case).
Truth be told, I think the better chance is to try some 16" wheels. But I dont have a lot of space to save the 18" rims and keep them. My best bet is to swap them with someone interested (their value is far more than 16" even if they are stock model).
I have had cars with 15 and 16" rims, never in any moment have I had any problems driving or road slipping (its just a 150hp car..)
Well to be honest, there is a truth to what you are saying. Also there is a reason in the fuel cap there is a note to the type of tyre you should use. A bigger rim can be good for a bigger engine due to its power. For a 220 cdi engine for sure it would be an overkill. But I do also think that maybe due to this car being a classic model maybe the front suspension and arms are not aligned for a 18" wheel.
Also an 18" wheel has a larger round diameter, and if the car is designed for 16" or 17" it is probable that it would change the responsivness (from what I read in a forum this was the case).
Fun fact: 20 years ago 18" wheel weren't nearly as common as they are today. Also, today you can get 18" wheels as appearance package, which has nothing to with power. Because they are so common today.
Yes, 18" wheel does change responsivenes, to better as you have less sidewall to flex.
As per review to the situation, after doing some digging on the owners manual of the car, the maximum allowed (except the weight of the rim) is 245/45 R17 tyre-rim size...which it translates in accordance to the 18" wheel diameter to actually the same size with 17" (except less sidewall). Attached as you can see, is the calculated size for each of the rims.
So on a technical standpoint, except the harsh ride/less fuel economy, the specs are about the furthest tyre size/model you can get (so you can't use 245/45 r18 tyre...I think it wont fit...).
But on my personal experience, don't go and buy some cheap chinese tyre. The first one's I had (Ardent was the brand) were very noisy. The harsh ride changed by 50% on the new tyres. Since it has such a narrow sidewall of course you need a well engineered tyre which should gice you a better comfort than the standart cheap makers you will find on your local garage.
Thank you all for the comments, notes and info! It is such a great value being able to share every experience which will help our community 🙏
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