Improved 5mpg on BFG K02

[jwkilgore]

Everyone there are 2 different ratings for these tires C rating maximum 50 PSI and E rating maximum of 80 PSI. One recommended pressure does not apply to another. BFGoodrich*All-Terrain T/A KO2 E rated tires

BFGoodrich*All-Terrain T/A KO2 C rated tires

No, there are three different ratings. The C and E ratings for LT tires you referenced above, plus the standard P-metric rating for Passenger tires. Everyone telling you that you're making a huge mistake in running 50psi is thinking about P-metric pressures. If you run a standard P-metric passenger tire at 50psi you'll jar your teeth out, wear the center of the tread, and run the risk of a blowout.

However, LT tires are designed to run at a much higher air pressure than P-metric. They require a higher pressure for the same load rating. So follow the advice of the tire manufacture (the people who actually made the tire should know what they are talking about). So 50psi for an E-rated (max pressure 80psi) on a 4Runner should be about right.

 

[ArthurHawk]

No, there are three different ratings. The C and E ratings for LT tires you referenced above, plus the standard P-metric rating for Passenger tires. Everyone telling you that you're making a huge mistake in running 50psi is thinking about P-metric pressures. If you run a standard P-metric passenger tire at 50psi you'll jar your teeth out, wear the center of the tread, and run the risk of a blowout.

However, LT tires are designed to run at a much higher air pressure than P-metric. They require a higher pressure for the same load rating. So follow the advice of the tire manufacture (the people who actually made the tire should know what they are talking about). So 50psi for an E-rated (max pressure 80psi) on a 4Runner should be about right.

I did not see this specific tire rated P, but in general yes there are 3 ratings I was referencing to these specific tires with current sizes.

 

[Northern 4Runner]

The trouble is an e rated tire is meant for a heavy truck, and not really a 4Runner. If you run an e rated tire at 32psi or in that vicinity you'll run the risk of very uneven tire wear.

 

[1engineer]

I don't believe you. Please show me the calculations and data or it didn't happen. Why? Because if this were the case and we could magically improve efficiency THIRTY PERCENT (!!!!) by running heavier tires with a rougher tread pattern don't you think the manufacturers would already be doing this? Never mind OEM'S spend BILLIONS a year to eek out a few mpg.
Sorry OP but your math is off by a factor of 10 or so.

 

[alfonzo]

I don't believe you. Please show me the calculations and data or it didn't happen. Why? Because if this were the case and we could magically improve efficiency THIRTY PERCENT (!!!!) by running heavier tires with a rougher tread pattern don't you think the manufacturers would already be doing this? Never mind OEM'S spend BILLIONS a year to eek out a few mpg.
Sorry OP but your math is off by a factor of 10 or so.

Though a bit of smart-ass answer, I agree. I also like the calk mark test.

 

[Friggin Idiot]

I can't imagine how rough that ride is at 50psi! I initially tried 40psi with my 275's (E) and didn't care for how rough the ride seemed over the stock Duelers. I ended up running 37psi and smoothed out the ride enough for my liking when driving alone. When trailering or loaded for long haul I have to add some air back in. 37psi is good enough for a daily commuter on variable fuel load and nothing else in the truck, but adding anything more than 2 people and it starts to feel mushy.

 

[Northern 4Runner]

I don't believe you. Please show me the calculations and data or it didn't happen. Why? Because if this were the case and we could magically improve efficiency THIRTY PERCENT (!!!!) by running heavier tires with a rougher tread pattern don't you think the manufacturers would already be doing this? Never mind OEM'S spend BILLIONS a year to eek out a few mpg.
Sorry OP but your math is off by a factor of 10 or so.

His mpg gains were comparing underinflated bfg ko2's to the exact same ko2's with 50 psi. Not comparing stock tires to ko2's.:doh:

 

[BlackWorksInc]

No, there are three different ratings. The C and E ratings for LT tires you referenced above, plus the standard P-metric rating for Passenger tires. Everyone telling you that you're making a huge mistake in running 50psi is thinking about P-metric pressures. If you run a standard P-metric passenger tire at 50psi you'll jar your teeth out, wear the center of the tread, and run the risk of a blowout.

However, LT tires are designed to run at a much higher air pressure than P-metric. They require a higher pressure for the same load rating. So follow the advice of the tire manufacture (the people who actually made the tire should know what they are talking about). So 50psi for an E-rated (max pressure 80psi) on a 4Runner should be about right.

This is partially true, but you need to consider that an E-Load LT tire is not meant for something as light as a 4Runner. These are the types of tires you see on "Heavy Duty" trucks that are running 8,000lbs trailers and so on, even then door jamb will only recommend running high pressures when towing. When you put such a stiff tire meant for such a heavy load on such a light vehicle and then inflate it to "working pressure" that tire is not being weighted down enough and is over-inflated because of that.

So while true that LT tires require more pressure, that doesn't mean that bumping it up to 50psi is going to be right for a an unladen, non-towing 4Runner.

I've seen guys throw LT Toyo MT's with bracket lifts on their Tundras and Tacomas, leave the tires at the 50~60psi the tire shop filled them up to and by their 1st 5k service those nice MTs are worn out and severely cupped and need to be replaced. The combination of crappy ProComp shocks not really tuned for the vehicle and overinflated tires just wiped out over a grand of shiny new tire. Then the customer gets mad at me because I have to break the news that all that money they just spent was a waste.

 

[Simpleman74]

This is why load range E tires are terrible on a 4Runner. You have to run them way under inflated to keep the ride close to normal.

And there is no way you just picked up 5mpg, give it a few tanks for your numbers to average out.

I run e rated at 45psi, chalks great and rides great. I also venture off the pavement so to say E rated tires are terrible..... is terrible advice

 

[1engineer]

His mpg gains were comparing underinflated bfg ko2's to the exact same ko2's with 50 psi. Not comparing stock tires to ko2's.:doh:

Read his OP. going from 17 to 20 mpg and then up to 23 mpg? That's not air pressure that's magic.

After thousands of results posted in the mpg thread that averages, on stock size tires, 17-20 mpg. He was getting 17 mpg with his KO2'S (average for stock tires combined city and highway) to 20 and to 23? Stock tires don't get 23 man. Air pressure adjustment will usually net you a half an mpg unless you go to ridiculous pressures and that gives you a mpg or so. Claiming 5mpg (his title) is dubious at best no matter what the tire.

 

[1engineer]

I run e rated at 45psi, chalks great and rides great. I also venture off the pavement so to say E rated tires are terrible..... is terrible advice

They are a terrible choice unless you are running off road in sharp rock or some other tire damaging surface. Did you gain 5 mpg?

 

[Simpleman74]

They are a terrible choice unless you are running off road in sharp rock or some other tire damaging surface. Did you gain 5 mpg?

hell no! Lol I think I lost 1mpg ish

 

[spawn]

I had been struggling with 17mpg for months on my newly installed KO2s. After reading a few threads, I thought I would post findings to save anyone any doubt.

I took pressure from 37 psi to 50 psi and I am now getting 20+ mpg. I even hit 23 mpg on freeway but that isn't an apples to apples comparison.

YMMV but definitely try increasing air pressure to improve mileage. Please be cautious and know if new air pressure is appropriate for your task at hand (towing etc)

Best,

Justin

23 freeway - tail wind?

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[proimion]

FWIW, I'm running LT265/70R17 Load C KO2 on a stock suspension at 38psi cold (what Discount Tire set it to on install). For the last 1,253 miles I'm getting exactly 18.0 MPG at an average speed of 27.6 MPH. I know this because I keep a detailed spreadsheet. :first:

Still, seems a tad underinflated to me, so imma bump it up a bit.

 

[cutty01]

Any rubbing issues with 275-7-R17? When I get my 4Runner I was planing on getting these same exact tires with same sizes.

Some don't and others have minimal rubbing. Every vehicle is different as it depends on your alignment (caster I believe). Even if you do, you can just do the fender liner mod or just use a heat gun and reshape the liner.

 

[DenverTrailRunner]

I simply e-mailed BFGoodrich to inquire about what pressure I should run these tires on my 4Runner. Attached is the reponse I got stating specifically 50psi.

Thanks for posting this email! I am getting the exact tires that you have installed later today and this is great to know.

 

[Northern 4Runner]

Read his OP. going from 17 to 20 mpg and then up to 23 mpg? That's not air pressure that's magic.

After thousands of results posted in the mpg thread that averages, on stock size tires, 17-20 mpg. He was getting 17 mpg with his KO2'S (average for stock tires combined city and highway) to 20 and to 23? Stock tires don't get 23 man. Air pressure adjustment will usually net you a half an mpg unless you go to ridiculous pressures and that gives you a mpg or so. Claiming 5mpg (his title) is dubious at best no matter what the tire.

I re read the OP's post, and he is definitely comparing all mpg to since he has installed his ko2's.

I pick up my 4Runner today, so I have very little knowledge (real world) of mpg's with these things, just stating what the op was comparing, and that was air pressure. No idea if it makes sense or not, or if it's even plausible. :reddance:

 

[LandCruiser]

I re read the OP's post, and he is definitely comparing all mpg to since he has installed his ko2's.

I pick up my 4Runner today, so I have very little knowledge (real world) of mpg's with these things, just stating what the op was comparing, and that was air pressure. No idea if it makes sense or not, or if it's even plausible. :reddance:

Real world is 13-17.

For reasons unknown I managed close to 19 blazing back from Huntsville in 110 degree heat.

 

[Runn4est]

We get about 18.5 for mixed driving and can actually eek up to 21 maybe even 22 mpg on road trips. When we had the stock LE wheels on we actually got 24mpg (ok more like 23.8:lieon a road trip! Yes, this was calculated, not using the computer.

 

[Simpleman74]

I guess my point is.... if you are worried about gas mileage, maybe the 4runner was the horrible choice not the tire:yo: