MPG frustration

[Timelord-SKO]

I've read twice now that on RV & semi truck tires the psi stamped on the tire is a minimum pressure, This was mentioned twice now in motorhome magazine.

Either way, the tires will say max or min. They don't tend to leave these things ambiguous. I'd go check what my tires say, but I am lazy. :biggrin:

 

[jazty]

I've read twice now that on RV & semi truck tires the psi stamped on the tire is a minimum pressure, This was mentioned twice now in motorhome magazine.

:-o

That's scary..

Maybe there are special RV tires that have a min and max printed?

I'll admit that I'd enjoy seeing an RV with tires inflated to 150psi bouncing down the road like a basketball!

 

[family wagon]

It certainly COULD be. But in my own experience... I never noticed a tire marked with a minimum inflation number. I've only seen maximum listed on the sidewall.

 

[cadillackid]

mine actually have the word Max so it wasnt confusion.. and I looked up the specs online for my tires and it says 120 PSI max cold. I dont remember a minimum pressure being stamped on the sidewall.. I'll have to look when im at the bus again..

both my drives and my steers have the same pressure markings on them..

-Christopher

 

[Tango-SKO]

Never saw a tire marked with a "minimum" pressure...only "Max Cold".

 

[Stu & Filo. T]

Ok I found one article in the January 2014 Motorhome Mag under the tech advice section, I tried scanning and attaching but it didn't work so heres a quick break down of question & answer.

Guy went to Les Schwab for tires balance & psi check,Les said to run tires at 90 psi instead of the 120 psi marked on tire.

The tech guys answer is; Their right in suggesting the lower psi," The psi molded into the sidewall is the tire manufacturer's" MINIMUM PRESSURE" when the tire is "CARRYING it's MAXIMUM RATED LOAD"

I knew I read something to the effect i just couldn't remember exact wording

Oh & lets make sure we're talking the same thing, I'm not talking tires on your car's or 1 ton trucks or short busses, i'm talking over the road truck & bus/RV tires

 

[porkchopsandwiches]

My 34' Thomas with a 3126b (electronic injection, 7.2 liter) does about 7-8 mpg usually with highway cruising. I've gotten 9 mpg like twice. My bus is pretty heavy at over 24,000 lbs. Not sure if this is normal for mine or not, but it has always been about that mpg for me.

 

[bread519]

Guys I am beyond frustrated. Tire pressure ok. All new filters. And still only getting 8mpg no matter what. A pedal to the metal, driving conservatively. Idk what's going on. Everyone says they get 8-12 and I'm stuck at 8 and it's absolutely killing me .

 

[AlleyCat67]

Not sure where mine is just yet.... filled the fuel tank when I first got it but haven't driven far enough to get a feel for the mileage... will certainly update when I know.

 

[EastCoastCB]

Guys I am beyond frustrated. Tire pressure ok. All new filters. And still only getting 8mpg no matter what. A pedal to the metal, driving conservatively. Idk what's going on. Everyone says they get 8-12 and I'm stuck at 8 and it's absolutely killing me .

I think I calculated mine at around 8 or so.
Not having an OD may be why we don't do quite as well as some who do?

 

[Geo Jeff]

8mpg would be amazing. My 40ft Alfa with c7 and 6 speed gets 6 mpg every where. I cant imagine the bus would get more but I keep hearing 8. Checking MPG its important to know every one is driving the same speed. Huge difference between 50 and 60 mph. Keep in mind that wind resistance between 50 and 55 is 4 times or 10times. I cant remember any more i use to do ECO racing for mpg. around 35 mph drag for the most part starts to factor in very little unless your pushing a sheet of ply wood.

Back in 1994 we had a new ford power stroke I think it was actually a banks system back then. Our enclosed trailer was way up over the truck. First race we went to we could not get the truck over 55mph and would start getting warm. Next trip we installed a sprint car wing on the roof of the truck and angled the wind over the trailer and you could drive right up to 70 with no issues a tall.

I bet this works with buses as well i know it has worked with every vehicle we have ever tried it on. but overdrive or your tall gear at 30 mph always gets you the highest MPG.
If you were on flat ground running out of fuel switching into high gear will usually give you 20 to 50 more MPG because you are not fighting any wind at all. The engine is just over a idle. If you over shot your tank of fuel and just didn't want to push the bus to the next station this might help. On my Geo's it takes you from 45 to 50 mpg to 70 75mpg. This true on most small cars and works on trucks like my old ford 5 speed. Forgot my wallet one night and though I would never make it home. It was early morning no traffic out of Seattle headed north. I just set the cruise control at 30 and jumped in the slow lane turned on my 4 ways and went 80/90 miles home on virtually no fuel. I pulled in my drive way and stopped and the engine died from the fuel sloshing in the tank.

 

[cadillackid]

I also believe that the 'E' engines are getting better mileage... I know in my case it seems to be.. granted my 2 busses are very different.. but at 65 in the little bird im getting close to what I get in the carpenter at 55.. and both have AT545 transmissions..

imagining I would do more If I updated the trans to OD and freshened the motor.. no plans to do that unless I start running into issues..

-Christopher

 

[prof_fate]

on full size buses we run 105 in the fronts and 95 in the rears.
No clue what the tires say to run, or the buses, was just told this for my CDL/P/S test.
it's what they find (the bus co) works best.

No idea on mileage, probably sucks as we drive slow and stop a lot..LOL.

It's interesting now that I've driven 7 or 8 different buses how individual they all are, even when they are claimed to be 'identical'.

today drove an older Int'l, more basic bus than the boss orders,been driving a new one the past week (as in 4300 miles on it). trained on a year old one (17k). Today the old one had 90k on it - noisier in most ways but seemed to have a lot more power. Not a fan of air wipers though!

No DEF, lower seats, no headlight warning alarm, no student left behind alarm, door open/lights buttons are not on the steerring wheel..felt like an antique. LOL

I should be getting this bus or the 'newer' one (same bus, just 65k on it) next week as 'my' bus.

as long as I wont blow up in a ball of fire for running my tires at 100 then im going to keeop doing so because running them at the 80 / 85 stamped on the bus label makes it a real Chore to drive... at 100 its all smiles for me..

the sidewall says max 120 PSI cold..

-Christopher

 

[cadillackid]

the busses will have tire pressures marked usually on the weight and ID plate above the driver seat or near the doors.. im told everything under the sun... some here say run whats on the plate... people that seem to drive busses for a livng that i tlak to in person say they run 100-110 cold PSI..

maybe large fleets do that just to make it "easy" to pump up the tires or check them on walkaround checks in the mornings.. esp if a driver switches busses..

I had thought about trying to find a nice 2006 Bus withy lower miles just to have the newest bus and have no DEF... then I found a 2000 for pretty cheap on auction and it has all the "features" I could want in s bus.... Air seat, air ride, A/C, tilt, Cruise, power front door, ABS, and as radio that works some of the time..

if I were you i'd go for the Pre-DEF even if it means you get a little older bus wit ha few miles... im not a fleet manager but i see what the DEF enabled pickup truck guys go through... in my opinion its still got a ways to go to be reliable..

plus its one more tank you have to keep full... from what i understand its not easy to disable or remove it without making the computer mad..

-Christopher

 

[ol trunt]

My shortie with it's 317 cu in turbo diesel gets 17 mpg highway and 14 mpg highway towing the 3000 lb toad. Like everyone else I had hoped it would do better

Jack

 

[2kool4skool]

On our last trip our little TC1000 gave us one tank at 14mpg. No towed, just the scooter on the rear hitch this time.

We run the AC always in the summer, often in the winter and our 7000 mile avg. is now 12.

55-60 mph.

 

[Geo Jeff]

on full size buses we run 105 in the fronts and 95 in the rears.
No clue what the tires say to run, or the buses, was just told this for my CDL/P/S test.
it's what they find (the bus co) works best.

No idea on mileage, probably sucks as we drive slow and stop a lot..LOL.

It's interesting now that I've driven 7 or 8 different buses how individual they all are, even when they are claimed to be 'identical'.

today drove an older Int'l, more basic bus than the boss orders,been driving a new one the past week (as in 4300 miles on it). trained on a year old one (17k). Today the old one had 90k on it - noisier in most ways but seemed to have a lot more power. Not a fan of air wipers though!

No DEF, lower seats, no headlight warning alarm, no student left behind alarm, door open/lights buttons are not on the steerring wheel..felt like an antique. LOL

I should be getting this bus or the 'newer' one (same bus, just 65k on it) next week as 'my' bus.

Michelin has a good youtube video on how to find your correct tire pressure. I know in the RV i have tire pressure monitors and the tires run much higher when warmed up like 20 or 30 psi. Takes a few trips to see them all and start to adjust them so They all read correctly. Nichole called two nights ago outside Houston while she was waiting for a tire change on the road. $330 bucks inside drivers rear. Only one that did not have a tire monitor on it. Last time it was off the the wrong valve stem was installed so you could not screw the gauge on. Tire monitor is your best friend. helps save tires and mpg and you from crashing. If you have never watched a video on how to drive the bus when a front tire fails it worth doing. Nothing like the chassis trying to make a left or right turn on the freeway in traffic.

 

[bread519]

Filled tank to full today so I could retest by holding foot more steady regardless of hills, and not exceeding 55 ever. Out of a 46 mile quick trip, I used approx 3.88 gallons which I rounded up to 4 because it's a bit tough to get the exact amount of fuel in these tanks as before. 11.5 MPG. I am going to scratch a "fill line" on the mouth of the tank and re test tomorrow.

Maybe I was just too heavy on the foot before? Idk. Previous owner said he floored it every stop and he still got 10-12. But I'm thinking terrain has a lot to do with that since he was from the desert in AZ and Texas. Here in the UP its moderately hilly everywhere. I did hit a few good straight always though, and at 2250 RPM 55 MPH you can't hear the turbo spooling, though as soon as I hit the smallest grade you can hear it. I am going to test at 60 next, then once more at 55 for a longer trip. happy though to say the least.

 

[bread519]

8mpg would be amazing. My 40ft Alfa with c7 and 6 speed gets 6 mpg every where. I cant imagine the bus would get more but I keep hearing 8. Checking MPG its important to know every one is driving the same speed. Huge difference between 50 and 60 mph. Keep in mind that wind resistance between 50 and 55 is 4 times or 10times. I cant remember any more i use to do ECO racing for mpg. around 35 mph drag for the most part starts to factor in very little unless your pushing a sheet of ply wood.

Back in 1994 we had a new ford power stroke I think it was actually a banks system back then. Our enclosed trailer was way up over the truck. First race we went to we could not get the truck over 55mph and would start getting warm. Next trip we installed a sprint car wing on the roof of the truck and angled the wind over the trailer and you could drive right up to 70 with no issues a tall.

I bet this works with buses as well i know it has worked with every vehicle we have ever tried it on. but overdrive or your tall gear at 30 mph always gets you the highest MPG.
If you were on flat ground running out of fuel switching into high gear will usually give you 20 to 50 more MPG because you are not fighting any wind at all. The engine is just over a idle. If you over shot your tank of fuel and just didn't want to push the bus to the next station this might help. On my Geo's it takes you from 45 to 50 mpg to 70 75mpg. This true on most small cars and works on trucks like my old ford 5 speed. Forgot my wallet one night and though I would never make it home. It was early morning no traffic out of Seattle headed north. I just set the cruise control at 30 and jumped in the slow lane turned on my 4 ways and went 80/90 miles home on virtually no fuel. I pulled in my drive way and stopped and the engine died from the fuel sloshing in the tank.

Haha awesome concept!

 

[CaptSquid]

When I purchased Brunhilde, I drove her back to Montana from Illinois, largely highway driving at 65 mph, flat out. I didn't know at the time how big the tank was (100 gal), so I resorted to filling at about 50-75%. The entire distance, I got 7.5 mpg. It never varied.