..concerning Superduties by email.

I have a couple of concerns.

One is the rattle, the latch on my armrest is loose and driving me crazy. I called my service writer today at the Ford dealership and he says He is worried if he orders a new armrest <lid> it MIGHT not fix it. He's going to call Ford and see if they have addressed this issue or if there is one. Someone else has reported this complaint on here also.

The second, is I stumbled across a thread on another site about getting worse MPG after the Flash, Now conicedently I am also. But I did go to a bigger tire than stock. My lie-o-meter was consistantly showing 22-23mpg before the flash and tires.<Same day purchase> I only went to a 295. Same size rim. Shouldn't make that much of a difference. I can only get 18.5 babying it all highway. Just can't tell if it's the tires or OTHERs have reported the change in MPG after the flash.

Shane

 

Shane -

The bigger tire might make a difference... I can't recall but my original 265's revs/mile was like 5% different than my 285's.. In effect that would make the lie-o-meter off 5% on my mileage..

I got a spreadsheet that multiplies by 105% to get "actual Mileage"..

So that could make up some of the difference...

 

Hi Shane,

I've not heard of anyone reporting worse fuel economy after the flash, mine has been about the same.

Bigger tires are less efficient, there's no way around that. More aggressive treads and more rubber on the ground will have more rolling resistance, and the larger diameter will make your speedo and odometer off, thus your MPG calcs will be off because you're really travelling more distance than your truck thinks, which will make your MPGs artificially low on your lie-o-meter.

At the risk of sounding blunt, this is not Ford's problem. You did this to your truck, not them. I'm jealous though, I hate the look of my stock 245/75R17 rubber bands...

 

Shane, not sure if this will help your situation or not but if you use the calculation below and determine actual size of your old and new tires, you should be able to arrive at the % of difference you should see as a result of the tire change. Of course, it will not account for weight or resistance differences.

Circumference Equation:
[(width * ratio * 0.02) + (rim * 25.4)] * 3.1415
<o></o>
Steps:<o></o>
1. Multiply Width, Ratio and 0.02<o></o>
2. Multiply Rim and 25.4<o></o>
3. Add Step #1 with Step #2<o></o>
4. Multiply Step #3 with 3.1416<o></o>
5. The result will be the circumference of your tire in mm.

 

You can also get on the tire manufacturers website & get your original tires (Conti's?) Revs per mile & then see what your new tires Rev per mile -

Mine was - Old 661 RPM vs 630RMP = 31 RPM less on new (like 5%) throwing off computers calcs & odometer...

 

IMO...why not for go all the hand calculated...and go visit your local dealer service dept. They should be able to adjust the REVS per mile from the OLD to the NEW. If you do that, then your speedo will be back to OEM...and so should your lie-O-meter.

The biggest benefit...is that your tranny will thank you. By changing tire size...this also affects shift points in the tranny. Which could cause an over heated tranny during summer months.

You paid for the tires...now go pay to change the REV per Mile. If you do...make sure to report back. I'm sure the other 2011 SD Owner's would appreciate it!


biz

 

My mileage before and after the flash are pretty well the same. 18.5 - 19.3....
I have never hit the 20.0 mark.

--
Gordon

 

There is NO WAY to contact someone at Ford direct,you get these customer relations people that dont have a clue and dont help at all in my Michelin Tire case as if had someone close it would have never went as far as it will in the near future.