E320CDI W211 fitting 235 tyres instead of 245 on 17" wheels

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I do not count DitchFinder-, DitchFinder and Ditchfinder+ or even Ditchfinder++ brands.

I hardly think that the Michelin crossclimate+ can be described as ditchfinders.

(They also have Goodyear’s, Bridgestone, Avon, Dunlop, Khumo, all good tyres)

Hope you find some that suit you.
 
Because of speedo accuracy which is setup on the basis of 245/45/17 ratio. In order to maintain that accuracy 235 in 17” would probably have to be something like 235/48/17 and 225 in 17” would be 225/54/17 and just immagine the prices of those.

OK lets do some calculations:
Rims 17" is 432mm
Sidewall of 245/45/R17 is 0.45*245=110mm
Sidewall of 225/45/R17 is 0.45*225=101mm

So:
Total radius of 245/45/R17 is about 542mm
Total radius of 225/45/R17 is about 533mm

So the difference in radii is less than 2%. That is if speedo is calibrated for 245/45/R17 than with 225/45/R17 the speed will be over-stated by just under 2%. Given that regulations allow very genrous tolerances for understating the speeds I can not see a problem with MB approving 225/45/R17 (unless they are so lousy with their speedo that even with 245/45/R17 it over-reads by the maximum allowed - 10% which would be a joke for a premium class car.). However they did not even bothered to approve 235/45/R17 that would give a speedo over-read of under 1%.
 
Michelin CrossClimate repeatedly get top marks in almost every tyre test review.

But if Michelin CrossClimate+ are available for the OP's car, I would not hesitate buying them if I was in his position.

CrossClimate+ are available for my car. They are considerably less suited for my car and the way I use it than TS860 or TS850 (love driving when there is snow, drive more in winter than in summer, drive mainly at night when it can be quite cold even in summer in the UK).

However even as of this morning I was inclined to reluctantly buy Michelin CrossClimate+ .... until I changed to winter tyres my elderly family's member car....

He bought brand new Michelin Pilot Sport4 just 4 months ago. A single trip to the continent (nice motorway driving) and a bit of driving there by the gentlest of drivers, perhaps 2000-2500 miles in total .... and the thread depth is as low as 5mm!!!!!!!! What a joke!!!

In contrast I had Continental WinterContact 215/55/R16 for about 5 years, driving those winter tyres all seasons, I am not the gentlest of drivers and yet they still have 4mm left!!! (Both cars are facelift E320CDI, and while he had proper 245 tyres and they did not last I had improper 215 tyres that lasted much longer than I ever hoped!)

So I am now inclined towards the 2 generations old and decade old TS830s hoping that they are not much worse than TS850....
 
OK lets do some calculations:
Rims 17" is 432mm
Sidewall of 245/45/R17 is 0.45*245=110mm
Sidewall of 225/45/R17 is 0.45*225=101mm

So:
Total radius of 245/45/R17 is about 542mm
Total radius of 225/45/R17 is about 533mm

So the difference in radii is less than 2%. That is if speedo is calibrated for 245/45/R17 than with 225/45/R17 the speed will be over-stated by just under 2%. Given that regulations allow very genrous tolerances for understating the speeds I can not see a problem with MB approving 225/45/R17 (unless they are so lousy with their speedo that even with 245/45/R17 it over-reads by the maximum allowed - 10% which would be a joke for a premium class car.). However they did not even bothered to approve 235/45/R17 that would give a speedo over-read of under 1%.

You have really worked all that out for nothing?

Don`t forget we are now ECU controlled cars and not way back in the 70`s / 80`s

Volvo back in 1998 the ECU can reset the speedo reading in a controlled procedure so i dare say MB with all it`s codes in the ECU can do the same so speedo accuracy is no problem with ABS and ECU motors.

The thing is when a car is first produced it is designed around safety .....if the car can control itself at speed and also traction with a powerful engine from standing starts to fast cornering. Whether you do all these things when driving is of no consequence but if you do use them and the car cannot control them properly then all hell is let loose with the manufacturer.

Which is why insurance companies will jump on those idiots that simply change the details and safety components of their motors.

Tyres are supposed to have their sidewalls vertical for optimum performance when fitted on the rim at the required air pressure if you come down on size of tyre you should come down on size of wheel J if you go up the same applies .....there is a very narrow margin to be spot on legal which is why i suspect MB don`t agree with the next size down being fitted.

When you buy a car you should understand what you are buying and why it is the way it is built and not just come along and alter the spec. and risk the lives of your kids and family and most of all other road users. Owners do the same with brakes etc. and other aftermarket components.

If you can`t afford to run the car as it is you should not own it!

I have 245/45/17 on my C 320cdi on the rear and the Goodyear Assymetric 3 are around £100 the staggered smaller size on the front were around £85 which i believe is a bargain for that type of tyre.
 
You have really worked all that out for nothing?

Don`t forget we are now ECU controlled cars and not way back in the 70`s / 80`s

Volvo back in 1998 the ECU can reset the speedo reading in a controlled procedure so i dare say MB with all it`s codes in the ECU can do the same so speedo accuracy is no problem with ABS and ECU motors.

The thing is when a car is first produced it is designed around safety .....if the car can control itself at speed and also traction with a powerful engine from standing starts to fast cornering. Whether you do all these things when driving is of no consequence but if you do use them and the car cannot control them properly then all hell is let loose with the manufacturer.

Which is why insurance companies will jump on those idiots that simply change the details and safety components of their motors.

Tyres are supposed to have their sidewalls vertical for optimum performance when fitted on the rim at the required air pressure if you come down on size of tyre you should come down on size of wheel J if you go up the same applies .....there is a very narrow margin to be spot on legal which is why i suspect MB don`t agree with the next size down being fitted.

When you buy a car you should understand what you are buying and why it is the way it is built and not just come along and alter the spec. and risk the lives of your kids and family and most of all other road users. Owners do the same with brakes etc. and other aftermarket components.

If you can`t afford to run the car as it is you should not own it!

I have 245/45/17 on my C 320cdi on the rear and the Goodyear Assymetric 3 are around £100 the staggered smaller size on the front were around £85 which i believe is a bargain for that type of tyre.


Are you an engineer (as I am a scientist and a lot of people in the family are engineers)? If safety is compromised by fitting a 235 tyre on 8J 17 wheel instead of 245 tyre than I would say the car is just unsafe and full stop.

As far as risk to myself, my family and others is concerned I would be a lot more worried about:
1. Driving with summer tyres on snow / ice / when temperature is at risk of being below zero - would argue it should just be made illegal, possibly under exiting laws - it is dangerous diving.
2. Driving with budget tyres.
3. The difference between various "Premium" brand tyres which can be a huge as some vendors call even Avon's premium.
4. People driving on close to legal limit tyres as performance declines extremely rapidly below 3mm.
 
CrossClimate+ are available for my car. They are considerably less suited for my car and the way I use it than TS860 or TS850 (love driving when there is snow, drive more in winter than in summer, drive mainly at night when it can be quite cold even in summer in the UK).

However even as of this morning I was inclined to reluctantly buy Michelin CrossClimate+ .... until I changed to winter tyres my elderly family's member car....

He bought brand new Michelin Pilot Sport4 just 4 months ago. A single trip to the continent (nice motorway driving) and a bit of driving there by the gentlest of drivers, perhaps 2000-2500 miles in total .... and the thread depth is as low as 5mm!!!!!!!! What a joke!!!

In contrast I had Continental WinterContact 215/55/R16 for about 5 years, driving those winter tyres all seasons, I am not the gentlest of drivers and yet they still have 4mm left!!! (Both cars are facelift E320CDI, and while he had proper 245 tyres and they did not last I had improper 215 tyres that lasted much longer than I ever hoped!)

So I am now inclined towards the 2 generations old and decade old TS830s hoping that they are not much worse than TS850....


I do accept that there are less tyre makes to choose from at the size your car came with.

And I accpet that the model of tyre you had your heart set on is not available in a the size approved for your car by the car's manufacturer.

And I also accept that you do not like the Michelin CrossClimate+, that are available in a size suitable and approved for your car.

But at this point I have a difficulty in understanding the exact nature of the issue that you have with the CrossClimates.

E.g.:

You say: "They are considerably less suited for my car and the way I use it than TS860 or TS850 (love driving when there is snow, drive more in winter than in summer, drive mainly at night when it can be quite cold even in summer in the UK)."

But you do not explain in what way the CrossClimate+ tyres are 'less suitable' for the way you 'use the car' compared to the other tyres you mention?

You say: "He bought brand new Michelin Pilot Sport4 just 4 months ago. A single trip to the continent (nice motorway driving) and a bit of driving there by the gentlest of drivers, perhaps 2000-2500 miles in total .... and the thread depth is as low as 5mm!!!!!!!! What a joke!!!"

You are offering anecdotal evidence from someone who used Pilot Sport 4 tyres on an unknown vehicle (FWD? RWD? 4WD? SUV? etc) under unknown conditions (tyre air pressures? Tracking? Geometry? Etc) suggesting rapid tyre wear - which is actually consistent with sports tyres due to softer rubber compared to eco tyres etc - and you do not explain in what way this anecdotal evidence is related to your current tyre conundrum?

I bear no ill feelings to yourself, but reading your posts I do get a sense that you are angry about the fact that the tyre you want is not available in the size that is approved for you vehicle, and that is understandable.

But at the same time some of your posts are incoherent and to my mind are lacking focus and devoid of logical analysis of the situation, its causes, and the options available to you at this juncture.

Instead, you aim your rant at the car manufacturer and at the insurer, and reject out of hand the solutions offered by other forum members.

Again, I have no axe to grind, but it is becoming evident that your predicament will not be resolved through this thread.

I wish you all the best with your quest to find tyres that work for you.
 
You are offering anecdotal evidence from someone who used Pilot Sport 4 tyres on an unknown vehicle (FWD? RWD? 4WD? SUV? etc) under unknown conditions (tyre air pressures? Tracking? Geometry? Etc) suggesting rapid tyre wear - which is actually consistent with sports tyres due to softer rubber compared to eco tyres etc - and you do not explain in what way this anecdotal evidence is related to your current tyre conundrum?

Well, any non-scientific evidence can be called anecdotal. But then as far as I am concerned, my personal experience does carry a lot of weight when making decisions, especially in the absence of other reliable evidence.

In the same family we have two E320CDI (and this was made clear in the post you have quoted, by the way), both facelift, both RWD.

Number 1, is mine and I do not drive it too gently. TS850 lasted 15k miles and even now they are 4mm even though were used all seasons - something that is supposed to ruin winter tyres quick. They were also smaller size 215 55 R16 - a factor which would be expected to increase wear.

Number 2, older family member who drives gently. Michelin Pilot Sport 4 tyres after just 2.5k miles are down to about 5mm. Most of those miles were just two long motorway journeys. And yes I do not consider that adequate longevity.

So I think I have very sufficient grounds to be very happy with the longevity of TS850 and to be unhappy with Michelin Pilot Sport 4. I suggest it is not too illogical to then project that negative experience I had with Michelin Pilot Sport 4 onto CrossClimate+ and it is not too unreasonable to expect that Michelin CrossClimate+ will not prove considerably longer lasting than Michelin Pilot Sport 4.

I would argue very logical conclusions based on evidence available to me. So will be trying to get TS830P - though it looks like they are difficult to get and will have to buy them online and look for a fitter myself.

And yes, all this trouble would have been avoided and I would be able to get even better tyres, TS860, installed on my driveway (as opposed to take a delivery and look for a garage myself) for a much smaller price if Mercedes bothered to approve fitments other than 245.
 
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....I suggest it is not too illogical to then project that negative experience I had with Michelin Pilot Sport 4 onto CrossClimate+ and it is not too unreasonable to expect that Michelin CrossClimate+ will not prove considerably longer lasting than Michelin Pilot Sport 4....

You lost me there... I don't wish to sound argumentative, but I find this sentence bewildering. I am afraid to say that if you continue with this type of pseudo-logic reasoning, your tyre search quest may not get you very far... good luck.
 
And this is really getting ridiculous !!!!

The 245 45 R17 Continental Wiinter Contact 830P are actually not approved for facelift E320CDI - at least it would appear so based on
Mercedes-Benz E-Class 2007 - Wheel & Tire Sizes, PCD, Offset and Rims specs

Speed rating is H. For E320CDI approved tyres for 17" rims are only 245 45 ZR 17 95W. So can not install H rated tyres. Not sure whether can even install non run-flat without it being a modification as ZR means run-flats.


For E320 CDI 4-Matic however 245 45 R17 95H are approved so TS830 would be fine....
also they are approved for E420CDI (did no even know these exist) and even for E500.
 
And now verified to E-class Owners manual (pages 388-389) ..... beyond ridiculous....

For 17" rim for most E-class facelift the only approved winter tyre spec is:
245 /45 R17 99V XL M+S

So the person who just bought TS830P needs to call his insurer and quite a few others with winter tyres as they have to be V rated or above AND 99 load rated or above not to be a reportable modification.
 
Tyres are supposed to have their sidewalls vertical for optimum performance when fitted on the rim at the required air pressure if you come down on size of tyre you should come down on size of wheel J if you go up the same applies .....there is a very narrow margin to be spot on legal which is why i suspect MB don`t agree with the next size down being fitted.

This argument against allowing 235 45 R17 (in addition to 245 45 R17) on 8J 17 rim does not hold water given that 245 45 R17 is also approved by MB to be used with 8.5J 17 rim ... (they did not bother even to change ET compared to 8J, though one would assume they would have to do that - but no, both ET38)
 
This argument against allowing 235 45 R17 (in addition to 245 45 R17) on 8J 17 rim does not hold water given that 245 45 R17 is also approved by MB to be used with 8.5J 17 rim ... (they did not bother even to change ET compared to 8J, though one would assume they would have to do that - but no, both ET38)

You can go down to 225 on an 8.5j without issue (if approved for your model). I have read the range is 215-315 but I wouldn't want to try those extremes but 225 45 r17 is pretty much the standard winter tyre size on a few German cars even on staggered wheels.
 
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225 on 8.5j is the recommended minimum in general but leaves a very exposed alloy rim .

Had 225 45 18 on 8J all around on another car and went 245 40 instead .
 
225 on 8.5j is the recommended minimum in general but leaves a very exposed alloy rim .

The alloy rims that so many facelifts W211 came out with, including mine, are 8J 17 (R11 LA 17" 5 DOUBLE SPOKE DESIGN). I have no doubt whatsoever at this stage that 235 or even 225 tyres on these would be absolutely safe. Probably even safer if one fits the best tyres available in 225 vs in 245.

The issue is insurance. If a particular rim or tyre spec is not approved than you either have to declare it as a mod (major inconvenience, major expense) or risk invalidating your policy. You could have paid tens of thousands in premiums over the years, they might even pay out a smaller claim or two but if there is a big claim chances are they would just refuse (or pay out third party if they have to and pursue you to reimburse it. Remember that question whether you are a homeowner when buying insurance?).

So the question than arises what is approved by the car manufacturer and hence, most likely, does not have to be declared, especially if winter tyres are put.

And here I had a saga:
1. I wanted the best on the market Continental TS 860 but not available in 245 45 R17 - the tyres face-lift E-Class generally came from dealership with. I was very frustrated but decided will go next down. TS830P...
2. The I discovered that TS830P are speed rated H, below an approved specification of V. Hence these to would be declared!!! So the only continentals winters are 810S. I might have been even prepared to extend my very positive experience with TS850 to TS810 or TS810P but sports? That would be too much....
3. I then looked even closer at my E-Class manual....and it looks like no 17" rims at all are approved for my car (and for the vast majority of face lift E-Class). So it appears that Mercedes have actually sold a car with unapproved rims and tyres (or with a major mistake in their manual). This now looks beyond ridiculous. I started a new topic as this is essentially a new issue of wider interest than whether I can put 235 tyres instead of 245 tyres on 8J 17 rims!

Approved Rims and Tyres for E320CDI Facelift (are 17" approved at all ?)
 
Couldnt be bothered reading every word as it got quite boring and a bit anal. Basically if the OP is rating tyres on reviews and a big leaning on spec \ safety etc buy the correct tyre and pay your money. Simples.
 

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