Advantage of a Larger Wheel? - PeachParts Mercedes-Benz Forum

EliotW · #1 08-20-2006, 02:30 PM

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?

t walgamuth · #2 08-21-2006, 05:53 AM

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

Dee8go · #3 08-21-2006, 11:09 AM

Quote:

Originally Posted by t walgamuth

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

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.

manny · #4 08-21-2006, 01:08 PM

Quote:

Originally Posted by EliotW

The amount of rubber on the road remains the same?

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.

Brian Carlton · #5 08-21-2006, 04:02 PM

Quote:

Originally Posted by manny

No. Your contact patch ( where the rubber meets the road....literally), will be considerably larger.

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.

t walgamuth · #6 08-21-2006, 08:11 PM

interesting point.

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

tom w

#7 08-21-2006, 08:33 PM

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

EliotW · #8 08-22-2006, 04:52 PM

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

Quote:

Originally Posted by t walgamuth

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

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

t walgamuth · #9 08-22-2006, 09:49 PM

if you have rough roads, probably that is best.

tom w