Tire size change
Posting Guru
Joined: Nov 2006
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This link is from the 6.0 PSD Tech Forum, it may proove helpful...
http://www.csgnetwork.com/speedocalibcalc.html
http://www.csgnetwork.com/speedocalibcalc.html
Postmaster
Joined: Aug 2006
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After rereading the OP's question, I start to wonder if anything is wrong. He just says it is different, this does not necessarily mean anything is wrong. I initially took different as wrong.
All I know is on a MY04 just changing the tires and not recalibrating the computer will not make the transmission do anything different that would be a problem. A transmission relearn should also not be necessary, unless you feel something is wrong.
When it comes to gearing, there would be no problem there as at 33" tall he is still within range of what would come out of the factory with a 6.0L and 3.73's. So even towing/hauling at max GCWR will be no problem, as long as the tires are load range E.
Now his fuel economy, if he is going by the vehicles computer it would be off. He would have to add 3.5% to the vehicles computer average to be correct. Being the difference of the new and old tire is only 3.5% the overall economy change should be minimal.
These are just my thoughts.
I would also like to wish everyone a Happy New Year!
All I know is on a MY04 just changing the tires and not recalibrating the computer will not make the transmission do anything different that would be a problem. A transmission relearn should also not be necessary, unless you feel something is wrong.
When it comes to gearing, there would be no problem there as at 33" tall he is still within range of what would come out of the factory with a 6.0L and 3.73's. So even towing/hauling at max GCWR will be no problem, as long as the tires are load range E.
Now his fuel economy, if he is going by the vehicles computer it would be off. He would have to add 3.5% to the vehicles computer average to be correct. Being the difference of the new and old tire is only 3.5% the overall economy change should be minimal.
These are just my thoughts.
I would also like to wish everyone a Happy New Year!
Posting Guru
Joined: Nov 2006
Posts: 1,154
Likes: 2
PowerStroke HD, that's about the same change I'll get when I finally get the Terra Grapplers in. They shipped me the correct size 285/75R16 but unfortunately in laod range D not in load range E like I ordered. At 32.8" they are 3.6% taller than the stock 31.6"tall 265/75R16E tires and will give me an effective gear ratio of about 3.59. I'll post an update on mileage and any shifting issues when I get them on and run a few tanks through the truck...
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melvinew2
1987 - 1996 F150 & Larger F-Series Trucks
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Jun 16, 2016 02:01 PM
