Tire size makes truck SLOW!

[02Oilburner]

I recently when from 315 75 r16 to 285 75 r16 and my truck seems like it is back to factory stock.(373 gears) It used to fly! Does changing tire size make that big of a difference? I get 20 mpg on highway but it is slow as hell from a stop. If this is the case Im going to save for new rims and tires this spring!!!

 

[big_rooster]

You are saying that your truck got slower with smaller tires? That makes no sense at all.

 

[mike.germann]

I'd look into another cause to the problem, maybe it recently happened around the time you got different tires? that's a trivial tire size difference.

Are you getting oil/fuel? Gauge readings?

Start with the small stuff and troubleshoot towards the bigger stuff as you go. Your wallet will thank you.

 

[rammertide07]

It makes sense that larger size tires would be faster on top end....and you would think that smaller tires would give you more torque on take-off. Those are custom tunes on your chip right? Was tire size taken into consideration with those tunes were written? That may have some affect on it....I'll have to think about that one.

 

[JLDickmon]

you sure those 315's were 75 series?

 

[rammertide07]

......

 

[BIG JOE]

you sure those 315's were 75 series?

Ditto....

 

[02Oilburner]

Hey guys! Sorry I just got home from my 2200 mile round trip Christmas vacation and was not able to respond.
Big Rooster= I was thinking the same thing that it should be a little faster off the line.

Mike Germann= I think I maybe having an issue with fuel delivery. On the way home yesterday at 4:00 am the truck started to loose power. I was in the middle of nowhere an nearly crapped myself!!! I forgot to tighten a connection on one of my fuel pumps before I left. Its one of those push on connections which is just a freaking STUPID design. I climbed under the truck and touched it and it came back on! It happened about 500 miles later so im going to look into fixing that and also get a fuel pressure gauge and oil pressure gauge also.

Rammertide07 Yes these are custom tune for my truck. I think I will have to call Jody at DP and see if it needs to be re-tuned for the tire size.

JLDickmon and BIG JOE yes it was. Here is the tire I had
Mickey Thompson Performance Tires & Wheels

Im going to check fuel filter and connections on pumps and see what I can find. I may also need to check IC boots for leaks and maybe my up pipes. They need to be replaced they are both the originals with over 400k miles. MY money pit just keeps getting deeper!!!!!

 

[dpantazis]

02-
you have something else going on, its NOT tire related. coincidence with tire change, yes.

fuel pressure gauge is not an easy or cheap one. not worth the money unless you are racing.

you will suck air from those QD fittings. look at the hutch mod to eliminate them.

programming will not be an issue with tire size. think about it, ford shipped these trucks with different tire options with the same programming. did jody ask you about tire size? i think not. he might have asked you about REAL variables like injectors and turbo, but not tire size.

check your MAF sensor too, or even change it out. they slowly get flaky but won't throw a code.

dp

 

[JRJ04]

02-

check your MAF sensor too, or even change it out. they slowly get flaky but won't throw a code.

dp

do we have one of those? is that the air flow restriction gauge that plugged into the factory box?