Changing the rears from 245/40/17 to 225/45/17 Good idea or not?

Bodhi

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Hello!

I want to fit all-weather tyres on my Merc, it currently have 225 at the front and 245 at the back. I got this car used, but I think it has these tyres at the back because its the C320 CDI, which means its relatively powerful. Can this be the case? I do not know.

That said, There are no all weather tyres in 245, which is why I want to ask your views changing them for 225. The size its a match in circumference, so no problems there, and because I am not planning to do any track days at all, I do think that I would be better with an all weather solution for the whole year, instead of having to not use the car if it snows.

What do you think?
 

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I’d look at what options you can fit - handbook and fuel filler inside lid should list the options.

I have a staggered summer setup on my SLK and a square winter setup.

I’d also check the wheel widths and see what size will fit.
 
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Bodhi

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Thanks. I did check, on the fuel filler is just the pressures, and on the handbook its confusing, as they mention all the C Class and the reference for the C320 says 225 on one page all around, and on another page 225 for the front and 245 for the rear.


I’d look at what options you can fit - handbook and fuel filler inside lid should list the options.

I have a staggered summer setup on my SLK and a square winter setup.

I’d also check the wheel widths and see what size will fit.
 

mioba

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handbooks can often be misleading as they can be printed before different options are available for cars - iE Tyres.

is your question more to the point of replacing the rubbers on the wheel with a different size rubber?

if so I would consult a few tyre places to be super sure. In person and not over the phone.
 
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Bodhi

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Thanks, sounds like a good idea. For instance I need to be sure that the rims are not wider than the ones at the front.

handbooks can often be misleading as they can be printed before different options are available for cars - iE Tyres.

is your question more to the point of replacing the rubbers on the wheel with a different size rubber?

if so I would consult a few tyre places to be super sure. In person and not over the phone.
 

onefortheroad

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Thanks, sounds like a good idea. For instance I need to be sure that the rims are not wider than the ones at the front.

Even if the rear wheels are wider you can still fit a 225 tyre along as the rim isn't wider than 8.5 j

Rim width (inch) Min. tire width (mm) Ideal tire
7,5 205 215 or 225
8,0 215 225 or 235
8,5 225 235 or 245
 
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AnthonyUK

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I have the same size f/r on a 17" set of staggered wheels due to wanting to use Crossclimate+ which aren’t available in 245/40r17.
They are rumored to be later this year though.
I’ve had absolutely no issues and the car originally came with 205s 16".
 
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Bodhi

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That's the one I want. Had it on my Accord and I love it. I think I will wait then, to see if they release the 245

I have the same size f/r on a 17" set of staggered wheels due to wanting to use Crossclimate+ which aren’t available in 245/40r17.
They are rumored to be later this year though.
I’ve had absolutely no issues and the car originally came with 205s 16".
 

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Why do you want all- weather tyres?
 
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Bodhi

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Thing is, you never know. Would you rather risk to be stranded in the middle of nowhere even for one day? Plus is not JUST snow, it is also ice, the all weather tyres will get you safer anywhere when temperatures go below 6 centigrade. Plus, they give you more than 90% of the grip of a full summer tyre. What is not to like?

Or do you have any powerful reason to stay away from all weather?


To avoid the 3 days of snowfall ?
 

onefortheroad

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Thing is, you never know. Would you rather risk to be stranded in the middle of nowhere even for one day? Plus is not JUST snow, it is also ice, the all weather tyres will get you safer anywhere when temperatures go below 6 centigrade. Plus, they give you more than 90% of the grip of a full summer tyre. What is not to like?

Or do you have any powerful reason to stay away from all weather?

I'll be fitting Bridgestone weather control as soon as funds allow . Or maybe imperial tyres which are half the price.
 

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Even if the rear wheels are wider you can still fit a 225 tyre along as the rim isn't wider than 8.5 j

Rim width (inch) Min. tire width (mm) Ideal tire
7,5 205 215 or 225
8,0 215 225 or 235
8,5 225 235 or 245

245 will fit in 8" wide rims
 

JBell

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You can happily put 225/45 R17 all round but you will need to check the rear wheel widths and maybe buy a pair of wheels to match the front.

One little thing though is they will look really small in the arches so maybe spacers to push them out.

I had 8x17" ET 35 wheels all round on my W203 Wagon fitted with 225/45 front and 245/40 Rear tyres
 

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I have the same problem, put XClimates on the fronts a while ago but could not find 245/40 R17's, however I was told that the XClimates in that size were available in USA and would be released in UK this autumn/winter, which was OK for me as the rears still have a decent amount of life left in them so I can wait. Worth checking with Michelin if they are releasing them soon!
 

Chrishazle

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Thanks JBell, haven't looked for a while, done so little mileage this year and rears are still quite good (GY Eagle F1 Assyms). Last time I looked at tyres was about Jan/Feb for the SLK (same setup as the S204) after getting the tracking sorted, didn't look at XClimates as have no intention of taking the SLK out in slippery stuff!
 


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