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Tyres size on new rims

SRang

New Member
Joined
Jan 31, 2020
Messages
23
Location
UK
Car
C220/w204
Hi , just got my new 19" 8.5J ET40 rims . I'm in doubt what tyres to fit in front , one tyre fitter told me he recommends 225/35 front and 255/30 rear because he checked somewhere in his catalogue, another one told me not to listen to him but to fit 235/35 front and 255/30 rear , he said he knows better ,been doing that job for 10 years etc. The car is 2014 C220cdi W204 saloon (not sport /not amg, not staggered ,all 4 rims are 8.5J) . Any advice appreciated Cheers
 
What does your handbook recommend, assuming the new alloys are of a size offered as an option on your model.
Generally speaking if the rims are the same width all round, then tyre sizes would also be the same.
 
What does your handbook recommend, assuming the new alloys are of a size offered as an option on your model.
Generally speaking if the rims are the same width all round, then tyre sizes would also be the same.
I dont have the handbook ,but the rims I bought are aftermarket ones , since my stock wheels are 16"s I guess then recommended one are up to 18" only anyway
 
235/35/19 on my 8.5x19 ET40 rim perfect, I say rim because I've got 9.5x19 with 265/30/19 on the rear, so personally I'd stick with 235/35/19 all round. :)
 
You don’t have staggered rims, so you don’t need differing tyre sizes. As above stick to one size all around.
(This will also allow full wheel rotations to even wear)
 
The tyre fitter told me its ok and even beneficial to put 255/30 rear ,no problem i have all 8.5j , he said 255 rear will make the car more stable ,and he's got that kind of set up to his Alfa Romeo .Im getting confused , but in fact I found a calculator for tyre comparing Tyre Size Calculator 225/35 and 255/30 in fact are quite the same size with less than 1% difference
 
The tyre fitter told me its ok and even beneficial to put 255/30 rear ,no problem i have all 8.5j , he said 255 rear will make the car more stable ,and he's got that kind of set up to his Alfa Romeo .Im getting confused , but in fact I found a calculator for tyre comparing Tyre Size Calculator 225/35 and 255/30 in fact are quite the same size with less than 1% difference
 
The same rolling circumference, yes but not the same tread width, which may or may not, be a problem with clearances.
I believe 18" was the largest wheel MB optioned with the W204, so you are outside recommended sizes. That's not to say they won't fit but yo're into insurance conflict territory (as it's a modification) and the MB suspension/geometry isn't set-up for the difference front to rear.
 
The tyre fitter told me its ok and even beneficial to put 255/30 rear ,no problem i have all 8.5j , he said 255 rear will make the car more stable ,and he's got that kind of set up to his Alfa Romeo .Im getting confused , but in fact I found a calculator for tyre comparing Tyre Size Calculator 225/35 and 255/30 in fact are quite the same size with less than 1% difference

A staggered tyre set up will have different wheel widths from front to back, you do not, so why bother with different sized tyres?
 
Technically you can have 255 both front and rear on 8.5 inch rims, whether 255 will 'work' on the front is another matter altogether. 16' to 19' is quite a big jump on a car like this IMHO. Let us know how you get on.:thumb:
 
Interesting, but in post 4,
" How does wheel size affect performance" They tested a Golf but I presume all cars are similar, they said 15" wheels 0-60 times are 7.6 secs, 19" wheels are 7.9 secs, hardly a big difference and you certainly wouldn't notice it, 0 - 100 is 1 second
difference, again hardly noticeable, and the bigger/wider wheel faster and more composed handling, put that together with bigger wheels look a LOT better, there's no real reason not to go for bigger wheels,
is there?:)
 
I just think the car might look a bit odd with 255/19 all round. It's up to the OP, bit late really as he already has the wheels but 245 is acceptable on 8.5 on the front with 255 on the rear maybe ? Not sure if the difference will be noticeable :dk: There is a good reason why most (if not all) performance cars have different size tyres/wheels front to rear.
 
There is a good reason why most (if not all) performance cars have different size tyres/wheels front to rear.

There must be a good reason the different sized tyres also have different width wheels too.
 

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