2nd Gen Non-Engine/Transmission -4 mpg because of BFG A/T???

[RussW1911]

I put stock size 265/75R16's on my truck a couple weeks ago and checked my mileage. Did these tires steal 4 MGP from me or do ya think I have other problems... . I started useing Howes meaner cleaner at the same time. I drive the same way all the time on trips and its the same route I take everytime. I would hope they wouldn't drag my mileage down that much.



I checked my IAT sensor and cleaned it. New fuel filter. Clean air filter. No boost leaks that I can find. Good tire pressure..... I can't think of anything else.

Thanks

 

[Cowboy Medic]

I have heard others say that BFG uses a harder compund which increases rolling resistance. I have BFG A/T's on mine size 235/85/r16. I had the General Grabbers before that same size. I actually have not noticed a difference. I average 16-18 in town 18-20 on 75mph interstate and can get up to 23mpg on a 55 mph highway. I think wind, and other weather plays more havoc than the tires do. One thing though is I am very conscientous about keeping inflation correct. I know that has made a huge difference for me at times.



Good thing with the BFG's is the wear. I have over 43,000 miles on this set. they are starting to look a little bald, but it is better than the 25,000 I averaged on my michelins and my grabbers. I will definitely go with the BFG's again.

 

[RussW1911]

Thanks Cowboy.....

I have another querry for the board. The max inflation on my tires is 65 psi. they still look like they are a little low because of the weight of the truck. Would I do any serious damage by upping it to say 70 psi. to see if that helps?

 

[OTRPU]

Beats me if it will. Personally I never exceed the sidewall max inflation. Running Coopers, 35 lbs max, haulin tri-axle 4 or 5 slide 5ers all over the country. They look alittle squatly, but wearing well and haven't blown.



Cheers,

Steve J.

 

[Cowboy Medic]

Sitting or around town driving probably not. Most of the time the tire pressure given is max cold. They are designed to accept higher pressure as a tire heats the air inside expands some. Where you would possibly get into trouble would be hauling a heavy load in warm temperatures. Without enough room to expand and no way to dissipate the heat, you could potentially cause a blowout. 5lbs over is not likely to put you at high risk. but your still taking a risk. My max PSI cold is 80lbs. I usually run it around 75,(on the front--- dually on the back I usually run 60-65) they look like they are a little bowed, but you also have to remember centrifugal force will even things out when you are rolling. My advice is not to exceed the max. Watch your tire wear and decide if it is wearing even. if it is you should be fine.

 

[Steve St.Laurent]

Are your BFG's larger than the other tires? If so are you taking that size difference into account in your calculations? I run 285/75R16's on my truck which are 10% larger in circumference than my stock tires were so I have to take whatever my odometer says and multiply x 1. 1 to get the true mileage. Just something to consider.



You don't want to inflate past the max inflation pressure. Look at the weight that your tire is rated for at that max pressure. My 285's are rated for 3305 lbs per tire at 65 psi and the heaviest unloaded are the fronts at 2200 lbs on each tire. I run mine at 55 front/45 rear unloaded and they wear flat. At 65 I would wear out the centers first and lose tire life driving around unloaded.

 

[RussW1911]

Same size

The tires I put on are the same size as stock, atleast the sidewall says they are. I haven't made any differences on my calculations for that reason. It should be the same. As far as inflation I am running 6 psi, thats the max and they still look squatty. I won't go over the sidewall max but will watch my wear closely to see what they do. On the last trip I made the tires didn't even start to warm up over outside temps.



Thanks guys, Russ

 

[Andy Redmond]

Howe's meaner cleaner? Some sort of injector cleaner?



I've noticed mileage drops when using this sort of thing (Cummins injectory cleaner). After you run thru a tank and the injectors are cleaned up, it usually goes back up.



Try switching to another brand of diesel too, maybe the jobber has got a load of blended diesel or some that's a little low on cetane.



I wouldn't think the tires would hurt the mileage that much since you stated that they are properly inflated.



You must have a load range D, BFG (65 psi max) an E load rating would allow for more psi (typically 80) as well as a stiffer sidewall. I had "D" rated Dunlop's last time (255/85/16) even after the speedo correction I think they hurt the mileage a 1/2-1 mpg.



My . 02.



Good luck

Andy

 

[Ramafid]

I use Howe's diesel treat twice a year and get much worse fuel mileage for the next two tankfuls. After that mileage goes back up. It usually drops 1-1. 5 mpg. Fuel at different stations can drop my mileage by as much as 2 mpg. Same size tires should not have too much effect on mileage. Must be a combination of things to see a decrease of 4 mpg.

 

[Turbo Tim 1]

I went from 235 stock michelins to 255 BFG Mud Terrains and only saw 1-2 mpg drop mostly due only to size calculations. I've gotta say it can't be because of the tires.

 

[RussW1911]

Thanks guys, I'm not going to put in the cleaner the next couple of tanks and see if it comes back up. Howes guarentees a mileage increase. But, guarentees have been renigged on before.

Keep any info coming that ou guys have.

 

[EBottema]

Tires cant make that much of a difference! especially a 20% drop in mileage... .



it has to be something in the engine causing it to not run as good... are you blowing lots of black unburned fuel? Check timing possibly???



If anything, its prob a conbination of many different things!

Erik

 

[CFAR]

my procomp m/t's are costing me about 2-3mpg, I think it is the more aggressive tread coupled with the softer sidewall

 

[OTRPU]

According to my DOC, I'm not to use any injector cleaner that states on the container that it removes water. Like those that have Isopropyl Alcohol and such. Injector seals will pay the price if I do. He makes a living rebuilding injectors & pumps.



Cheers,

Steve J.