Fromt and rear tyres different profiles?

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Robllew

New Member
Joined
Dec 1, 2020
Messages
7
Location
Sheffiels
Car
C250 CDI
Hi there, just come round to pricing some tyres up for my W204 C250. Noticed the fronts are 225/40/R18 whilst the rears are 255/35/R18. I understand the rear being wider than the front but not heard of them being a lower profile? Is this a common thing? Had the car just over a year and it's currently on Bridgstone all weather tyres but they're ready for a change.
 
That’s the correct fitment for a C class. My E class is the same 35 profiles on rear and 40 on front
 
The profile has to be lower on the wider tyre to maintain the same rolling circumference as the fronts
 
Spot on the theory , but real world differs with aspect ratio and tyre widths .
 
The profile number is the percentage of the width. You are all good.

40% of 225mm is 90mm sidewall
35% of 255mm is 89.25mm sidewall, iyswim

Spot on the theory , but real world differs with aspect ratio and tyre widths .

...and tyre wear (they do get smaller over time), and tyre pressures, but it a good approximation.
 
The profile has to be lower on the wider tyre to maintain the same rolling circumference as the fronts
How come the c63 has 245,35,19 front
265,35,19 rear then ?
Plus ive gone 275,35,19
 
How come the c63 has 245,35,19 front
265,35,19 rear then ?
Plus ive gone 275,35,19
The C63 has an actual staggered diameter setup (the rear tyres have a larger rolling circumference than the front). This is also standard on some models (my fronts are 255/35/20 and rears are 275/35/20).

It's possible to adjust the programming in the ESP module for this slight variation of circumference so the traction control still knows what's going on. (That it's normal for the rears to be rotating slightly slower than the fronts.)
 

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