[Guest]

Dear all,
I recently got back from Dallas. During strict highway-only driving I was getting a constant 31.2 MPG. I calculated it by the old method of topping off the gas and dividing the miles by the gallons used AS WELL AS taking the computer's word for it which showed me. Do you all get this type of mileage also? Is mine too low or higher than what most of you guys get on long trips?

 

[sosh]

I never saw this mileage when I had my W210 E320 4M. I usually averaged about 28.5 on the road at 70 MPH in level country. Your figure seems high to me was it mostly downhill, even a 1% grade or so average?? What ever is allowing this is teriffic I would just leave it alone as long as its running well.

 

[Musikmann]

My MPG, as far as I can remember, has never reached 28. Driving through Kentucky I regularly travel 200 miles each way, averaging about 68 MPH, but going 80 whenever I can. For what this is worth, my '98 E430 got almost the same MPG, on the same interstate highway, as the '01 E320 - I noticed between 26-27 with that.

 

[Raylee177]

Maximum I got on FWY driving on 2001 E320 was 30.5 miles per gallon with air conditioner on and off with my wife aboard.
31.2 excellent!

 

[Check Codes]

You always pay for the extra weight and friction of the 4matic in fuel economy, but you make it up on snowy/icy roads.

You're right in range with what I typically see. The absolute best I've ever seen on mine was a 200 mile run from Southern Arizona to west Phoenix, mostly level, running 70-75, 32.5 for that trip. I was stunned.

Typically I see right around 29-31 for steady cruise highway driving.

Take care and enjoy the ride,
Greg

 

[Yacht Master]

My MPG, as far as I can remember, has never reached 28. Driving through Kentucky I regularly travel 200 miles each way, averaging about 68 MPH, but going 80 whenever I can. For what this is worth, my '98 E430 got almost the same MPG, on the same interstate highway, as the '01 E320 - I noticed between 26-27 with that.

My 1999 E 430 cruise control @ 72 mph A/C on 26.5 repeatable, 27.5 best ever.
In town I am a lead foot hence the V8.

 

[mackmack]

mine is E430 and on the hwy ihe most i got was 26 mpg with the AC off, i think thats good for a V8

 

[Kajtek1]

The absolute best I've ever seen on mine was a 200 mile run from Southern Arizona to west Phoenix, mostly level, running 70-75, 32.5 for that trip. I was stunned.

Typically I see right around 29-31 for steady cruise highway driving.

The good mileage was on Arizona gasoline?
Nevada is selling Californian diluted gas.
I just topped off 40% of the tank in AZ going to Great Canyon and my mileage became unbelievable.
We have to burn more gasoline in California to protect the air.
Does it make sense to anybody?

 

[micosavo]

That is good mileage, at 60miles/hr on a 200 mile trip, my car averaged 32 also. The highest I ever saw on the computer was 34.9, but I was doing 50m/h for ages!

 

[Raylee177]

Tire size has effect on mileage also. When I switched from 215-55-16 original stock to Yr. '05 211 stock tire 225-15-16, mileage went down by 2 miles per gallon.

 

[Check Codes]

Tire size has effect on mileage also. When I switched from 215-55-16 original stock to Yr. '05 211 stock tire 225-15-16, mileage went down by 2 miles per gallon.

Actually, Raylee, your mileage really didn't drop. You increased the OD of the tires, thus making the odometer track fewer miles for the miles you actually drive. Thus, you go the same distance on the same amount of gas, but when you calculate it (or let the computer calculate it) the calculation will be off. By the same token, your speedometer also reads slower now by a few miles per hour.

That said, tire and wheel size can have a negative impact on actual fuel economy even if you maintain the proper OD. Larger/wider wheels are much heavier, so there is a true loss as more of the engine's power is needed to rotate them to begin with and to keep them rolling. And don't kid yourself, there is also a loss of cd on the front, and the added wind resistance will come into play as well. Anecdotally I've heard tales of people going from 15s and 16s to 19s and 20s and seeing a 15-20% drop in fuel economy.

But in your case, Raylee, the 211 wheels I think are actually a bit lighter than the 210 wheels and the mild increase in width shouldn't really impact cd, so overall I'd bet your fuel economy is exactly the same, the odometer just doesn't know how far you're actually traveling. (The side benefit, of course, is that your car will always reflect that it has fewer miles than it actually does, so maybe that will get you an extra $200 on trade-in way, way down the road. )

Take care and enjoy the ride,
Greg

 

[slybydesign]

Greg210, you sound like your well versed on tires, may I ask you something? When I first got my car 98 w210 the tire sizes where 225/60 16 all around, I just found out that was extremely wrong and dangerous and switched to 205/60 16 all around and now I feel like Im floating in mid air. What in your opinion would you say the difference will reflect in mpg/hwm/and etc. thank you, (sorry I typed the wrong size)

 

[Raylee177]

Gregs210,
as always, I thank you very much for that information. It really is a good piece of information. It sounds very logical. You just helped me get back my lost 2 miles per gallon that I thought I lost with the new tire set! By the way, I have no problem with the tires.
Have a very good day!

 

[Check Codes]

Greg210, you sound like your well versed on tires, may I ask you something? When I first got my car 98 w210 the tire sizes where 225/60 16 all around, I just found out that was extremely wrong and dangerous and switched to 205/60 16 all around and now I feel like Im floating in mid air. What in your opinion would you say the difference will reflect in mpg/hwm/and etc. thank you, (sorry I typed the wrong size)

Hey, Sly. I'm just glad you got the other ones off your car before the rubbing turned into "catastrophic failure".

The tires you're riding on should have the same OD as the ones Raylee has on his car, so just like him your odometer reflects less than the miles you actually drive. So your mileage is actually better than what you think it is. To the extent there is any actual effect on the car I'd think it might ever so slightly improve your mileage, because you're presenting slightly less rubber into the airstream of the car. Whether that would be enough to actually measure, I don't know, if you've got tens of thousands sitting around take it to an air tunnel and find out.

Hope you come down to earth soon.

Take care and enjoy the ride, folks.
Greg

 

[MRBSMITH]

Incredable!!

In the valley between LA and SFO( flat and straight), following trucks at 58ish I got 35.8 over 300 miles!!!

B

 

[slybydesign]

Hey, Sly. I'm just glad you got the other ones off your car before the rubbing turned into "catastrophic failure".

The tires you're riding on should have the same OD as the ones Raylee has on his car, so just like him your odometer reflects less than the miles you actually drive. So your mileage is actually better than what you think it is. To the extent there is any actual effect on the car I'd think it might ever so slightly improve your mileage, because you're presenting slightly less rubber into the airstream of the car. Whether that would be enough to actually measure, I don't know, if you've got tens of thousands sitting around take it to an air tunnel and find out.

Hope you come down to earth soon.

Take care and enjoy the ride, folks.
Greg

:bowdown: Thank you very much for the info. I am very happy that I switched b4 something bad happened. Now that I have the new tires, I feel like the car is super smooth on the road. I dont know if I wanna come down now, LOLOLOLOLOLOLOL