I just remembered, my tires are Chapparall or something like that
Non-Sexy MPG Advice
This is about as sexy as John Goodman in a speedo but it definitely works, particularly for heavy pickups.
Keep your tires aired up rock-hard.
This is a must for folks with firebomb tires but it makes a big difference on other brands as well.
I use 235-85 E rated tires and I keep them inflated to 80 psi, front and rear. Any more and the tire starts to "crown" - bulge out in the middle of the tread. That will wear the center of the tire out quickly. Not recommended.
My truck is very sensitive to this. If the tires get down to 70 psi, I lose 1 MPG. At 60 psi, 3 MPG. Ask me how I know that. Don't gundeck the tire inflation.
Keep your tires aired up rock-hard.
This is a must for folks with firebomb tires but it makes a big difference on other brands as well.
I use 235-85 E rated tires and I keep them inflated to 80 psi, front and rear. Any more and the tire starts to "crown" - bulge out in the middle of the tread. That will wear the center of the tire out quickly. Not recommended.
My truck is very sensitive to this. If the tires get down to 70 psi, I lose 1 MPG. At 60 psi, 3 MPG. Ask me how I know that. Don't gundeck the tire inflation.
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I know if they are "Overinflated" you'll see it wear pretty quick! 
dave when you slow down to stop or something, do you coast, let off the gas while still in gear, or down shift? and what RPM do you shift at?
I've heard that if you can keep the shifts below 2000 rpms they will do better.dave when you slow down to stop or something, do you coast, let off the gas while still in gear, or down shift? and what RPM do you shift at?
Trailerhauler asked:
"dave when you slow down to stop or something, do you coast, let off the gas while still in gear, or down shift? and what RPM do you shift at?"
Dave sez:
It depends.
If I see a stop sign or light coming up and I'm not being crowded hard by traffic, I kick into neutral and coast. Running empty on flat ground, I can usually coast a half mile or so - further if loaded on flat ground or downhill. The engine returns to an idle and I still have power steering/brakes. Real hard-core hypermilers shut off the engine but this truck is too heavy for that.
I don't coast in neutral with a trailer.
As a rule I don't downshift. Brake pads are cheaper than clutches and diesels without an exhaust brake don't give you much engine braking anyway. they only reason I might downshift is that I know that at the bottom I need to drop the hammer on it.
For upshifts, I generally shift at 1300 RPM. This generally drops you onto 1000 RPM which has plenty of torque for acceleration. Heavily loaded going uphill I shift at 1500-1800. Only time I my struck ever sees over 2000 RPM is when I underestiamte the gap in traffic and I really need to speed up fast.
"dave when you slow down to stop or something, do you coast, let off the gas while still in gear, or down shift? and what RPM do you shift at?"
Dave sez:
It depends.
If I see a stop sign or light coming up and I'm not being crowded hard by traffic, I kick into neutral and coast. Running empty on flat ground, I can usually coast a half mile or so - further if loaded on flat ground or downhill. The engine returns to an idle and I still have power steering/brakes. Real hard-core hypermilers shut off the engine but this truck is too heavy for that.
I don't coast in neutral with a trailer.
As a rule I don't downshift. Brake pads are cheaper than clutches and diesels without an exhaust brake don't give you much engine braking anyway. they only reason I might downshift is that I know that at the bottom I need to drop the hammer on it.
For upshifts, I generally shift at 1300 RPM. This generally drops you onto 1000 RPM which has plenty of torque for acceleration. Heavily loaded going uphill I shift at 1500-1800. Only time I my struck ever sees over 2000 RPM is when I underestiamte the gap in traffic and I really need to speed up fast.
alright, kinda sucks here with the 4.10 rear end. thinkin about gettin a 3.73 rear and some 19.5 wheels like deere slayer!! that should help and look good at the same time
Bigger tires will hurt your MPG.
Yeah, I generally shift between 1300-1500 and get pretty good city mileage.
I need to work on some aerodynamics so I can get decent highway miles
Dave, do you have any pictures of your bed cover?
I need to work on some aerodynamics so I can get decent highway miles
Dave, do you have any pictures of your bed cover?
There are pix of the cover and my air dam in the gallery.
Temporarily down for maintenance! haha, I'll check them later
I didn't think it would make a difference if you got bigger tires. But it's probably because they weigh more right?
either way I still want a set!
either way I still want a set!
Bigger tires can add rolling resistance and weight. Taller tires will throw off your speedo/odo and tranny shifting points.
It also adds more wind resistance by making your vehicle higher off the ground. It also allows more air to go under the vehicle. I may be talking out of my a$$ here but it sounds good in my head.
yeah, that's what I got to thinkin after I opened my mouth about not making a difference in milage.
Does anyone know how much worse the f450-f550's get?
Does anyone know how much worse the f450-f550's get?
That really depends more on gearing than anything else. A f450-550 with 4.30s will do better than a F450 with 4.88 gears. I think a F450-550 with 4.30s & the right amount of power would do about as good as a F350 with 4.10 gears. But then again too it depends how the truck is configured.....single, super, crewcab...wheel base length, flatbed, dump truck, 5th wheel hauler....Does anyone know how much worse the f450-f550's get?
That sorta stuff....
yeah, I know thier worse than 350's because of the gearing
well, i just checked my E rated tires that call for 80 psi cold, and they were 55 psi. No wonder why my mileage is such crap. I'm getting 12-13 mpg in town being nice with a 2wd f350 cc. And the local gas station compressors will not fill my tires to more than 70 psi :doh:
When the tire shop rotates my tires (free rotate & balance for the life of the tireswell, i just checked my E rated tires that call for 80 psi cold, and they were 55 psi. No wonder why my mileage is such crap. I'm getting 12-13 mpg in town being nice with a 2wd f350 cc. And the local gas station compressors will not fill my tires to more than 70 psi :doh:
) they always air them up to 65lbs. That way the whole surface of tire contacts the road & rides good & wears evenly. They said they don't even bother going up to 80 unless your hauling something heavy.
Yeah, but you'll have less rolling resistance with more air in them, thus resulting better fuel economy.
I didn't buy 265 Mud radials because I was after MPG. In all truth though I don't notice much diffrence MPG wise in a 235 aired up vrs. a 265 except that the 265 rides ALOT better. The last owner with had a camper shell that sat flush with the cab roof & a stock exhaust with 235 A/T radials & said he normally saw 14mpg. I got it & straight piped it & pulled the camper shell off, installed a set of 265-75/16R mud radials & was regulary getting 16mpg when I drove it easy & 14mpg when I was harder on it in the summer.Yeah, but you'll have less rolling resistance with more air in them, thus resulting better fuel economy.
One time I tried to keep a set of 235s aired up to 80lbs but the ride was horriable & when they heated up they would get over 80lbs resulting in the center of the tire to wear down rather quickley. Not a great idea in my book. It can be done but with how often the temps change around here I don't feel like stopping to check the tire pressure all the time.
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