Using a calc that EBennz posted I compared the stock wheel/tire combo of the W124 E420 to the largest possible upgrade (without rolling your fenders).

Stock
195x65x15

Upgrade
225x45x17



It appears your just trading sidewall height for wheel height? The amount of rubber on the road remains the same?

the short sidewalls will give a more immediate response to steering input off center. also larger wheels give more room for bigger brakes.

for ordinary driving though, the very short sidewalls are a lot more vulnerable to chuchholes. i saw a car recently along the road with a flat very low profile tire and an obviously bent rim.

also if the wheel tire combo is heavier than stock it will contribute to a worse ride and less adhesion on bumpy turns as the wheel will tend to float over bumps rather than follow them.

for me sticking with stock seems best most of the time. the exception is when tire availability is an issue, which seems seldom with a benz.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Tom, it sounds like low profiles tires would not do for the District of Columbia. A ride down most streets there would confirm to you that funding infrstructure in our nation's capitol is not a high priority for the DC government.

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" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

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No. Your contact patch ( where the rubber meets the road....literally), will be considerably larger. ( 195 mm vs. 225 mm tread width ).
Also, the " rolling resistance " will be a little higher, i.e. gasmileage may go down VERY slightly.

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2007 C 230 Sport.

Unless the vehicle got magically heavier during the tire change, the contact patch must remain the same at a given pressure. In this case, the patch gets wider, and, therefore, it must also get slightly shorter.

You can, of course, increase the contact patch by decreasing pressure in the tire.

interesting point.

absoultely true i am certain but i never thought of that before.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

A (heavier) larger wheel will require more energy to decelerate, affecting braking performance.

I saw an Exiige in Georgetown a few weeks ago... can't imagine how long that will last.

That makes sense... thanks for taking the time to explain. I'm out in the country here and some of these roads warrant an off road package. I think I'll leave my 15' wheels well enough alone

if you have rough roads, probably that is best.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.