if rims size identical...can... if very different then cannot

need rim info tbh

Need more info. What car and what are the sizes for the front and rear. Might have a staggered setup from the factory.

need the rim width...

example ori BMW front can be 8" wide...rear 9"... here you cannot use 4 identical tyre size

tell us the front/rear tyre spec we should be able to deduce

Need more info. What car and what are the sizes for the front and rear. Might have a staggered setup from the factory.

Good dry and wet grip. Great for some spirited driving

Nonsense! My rims are 18x8 front and 18x9 rear and I just use same 245/40/18 on all 4! Tire size also got range if fitment possible so like 245 can fit for 8-9.5jj width.

TR1 btw some say ok but I have also heard bad comments on it saying the grip is not good, so not sure.

yeah... tbh for this profile... 10mm difference from 225 vs 245 not that noticeable... but a lot depends on the sidewall too... 235 probably a good compromise

btw cant generalized smaller front = understeer... got many factors involved... also understeer is preferred and safer for 99.9% of people... imho all the cars are designed slightly understeer anyways...

edit: do you rotate your 9jj to the front?

buy a pump...don't use run flats... then everything becomes cheap...

What sensors?? Often they just talk only coz they don't know how to explain and just take the easy way out.

As he mentioned above if change width also need to consider the sidewall height because 245/40 is taller than 235/40 but less than 235/45. What are your actual sizes now? (Sorry if already mentioned before, I might not notice it).

weird profile combo tbh... you bought used car?

maybe you mean 225/45 + 245/40?... 235...40 or 45 should not be a problem... BUT really you should check your rim size like I said... I dunno what is fitted and dunno any overlap... so don't want to give wrong advice

Ya very unbalanced combo. The front is way too small in rolling diameter, very thin profile, while the rear is very tall sidewall!  Difference in sidewall height is a massive 2cm! Your car must be low at nose while the rear sticking up, and the fender gaps at the front is much bigger too. Stock Merc C class should not be like that. Are you sure they're not 225/45/18 and 245/40/18??

Ya very unbalanced combo. The front is way too small in rolling diameter, very thin profile, while the rear is very tall sidewall!  Difference in sidewall height is a massive 2cm! Your car must be low at nose while the rear sticking up, and the fender gaps at the front is much bigger too. Stock Merc C class should not be like that. Are you sure they're not 225/45/18 and 245/40/18??

anyways... 235*4 is probably about same cost as 225*2 + 245*2

don't think you gonna save much... just give you some flexibility in terms of rotation if uneven wear

Yeah I also suspect as such, so max can only go 235/45 but will be about 0.5cm taller sidewall, will be slightly heavier but more comfortable. Handling might be slightly more neutral but not much noticeable if just normal driving.