LOL, yes it is very confusing. Once you go over several pages in different sections of the owner's manual it starts to make sense.

From what I've heard about Germans, they probably need to know how to calculate loads and adjust tire pressure accordingly. I've heard the tests and level of knowledge is very stringent over there.

 

Yes I followed the Manual for 2014 C Class available on the MB website . I have even quoted the lines above from the manual when michail71 and I were discussing about this. Here is the exact line :


Tire and Loading Information placard on the B-pillar on the driver's side of the vehicle (Y page 326). The Tire and Loading Information placard contains the recommended tire pressures for cold tires on a fully loaded vehicle and for the maximum permissible vehicle speed.

 

At first glance it looks confusing, but I think the disrepency is made by our laws more so than MB.

The pressures in the door are legally required in the US. So they have to list the max pressure period to comply with the law. The fuel door then gives the correct information with the added note that the max is for specific cases and generally you should be 3 under max.

 

That's the problem, on the fuel door it says "max load" and next to it are the pressures to use. If they would have just had the pressures and then below go into something about what the pressures should be for those kinds of extreme conditions that would make it much more clear.

 

I can understand the reason for confusion and ambiguity, but I think it makes sense as written. The fuel door is correct in that is the max you should put in the tire as shown... Except for the special case of over 100Mph where you'll need the extra +3 PSI.

As I mentioned earlier, the door has to list the overall max period due to the US requirement that they put it in this fashion.

 

Hmmm, both my door jamb and fuel door say Front 28psi Rear 33psi (2010 C300 Sport RWD).

When filling the tires I kept the car running and used the psi numbers on the dash, I wonder how reliable that is... I reset the data to the current psi when Ihad exactly 28psi in front and 33 ipsi in back and I have seen the numbers dip as low as 23 and as high as 36 without any warnings.

 

I've found my TPMS numbers to be very close when measured with a good gauge. Once I got the bleeder valve and got them all the same they usually match up or differ by 1 psi.

Does you fuel door have multiple values? Some examples the owner's manual show indicates it could be a table of load/pressure values. On mine it just has the blurb to add +3.

 

So are you saying it's better to have more like 40psi+ or less pressure for the back? I have the same issue with the inside shoulder of the rear tires. I thought it was an alignment issue mostly..

 

Correct tire pressure as per MB factory for the 204 for the 4matic version (17") staggered is 28" front and 33" rear.

Over the years to comply with regulation, MB upped the tire pressure to improve fuel economy. So if you care about ride, stick to the above, if you care about fuel consumption, go nuts.

This is as per MB Canada. I have the official tire pressure document and have uploaded it in the past.

 

My 2012 C300 4MATIC Sport with 17" staggered wheels (225/245) says 33 Front and 38 Rear on the gas cap and 36 Front and 41 Rear on the B pillar. Talk about fuel consumption care from 28 and 33!

 

My C350 with 18" AMG wheels shows 36/39 in the fuel filler and 39/42 on the door jamb, as mentioned before +3 to each. I run my car at 35/35 as I see no reason to use such a high pressure in back ... in another thread the conclusion was that the higher pressure in back was just to max out gas mileage with no other benefit (42 psi on a C250?). My car rides nicely with no noticeable tire wear issues in back.

 

An increase in tire pressure is purely for fuel economy reasons.

I run my 2012 C300 at the specified 2008 tire pressure, of 28psi front, 33 psi rear.

To summarize, i'm quoting from Mercedes Benz Canada in an email they replied to me with.

"2008 C300 with staggered 17” tires Front: 225/45 (28psi) Rear: 245/45 (33Psi)
C300 4MATIC (up to March 2011) with staggered 17” tires Front-30psi Rear-35psi
C300 4MATIC (as of March/2011) with staggered 17” tires Front-33psi Rear 38psi"

 

I typicaly run the recommended pressures or close to them, 30PSI in front and 35PSI in the rear. However, when I'm doing long trips on highway, I bump the front and rear to 40psi, car is smoother on the highway, more efficient and I feel the increased handling due to reduced roll. I do have to be careful not to hit pot holes haha.

 

Using the factory (door frame) numbers seem fine (and no noticeable wear in 12,000 miles - 9/32 F & R).

Ride firm but not jarring also.



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