Speed Limiters

[nobb4u]

I am one who said they would not set the speed limiter on my truck, but that being said I never speak in absolutes.

A few weeks ago I was offered a super paying load going to Ontario the rate being one I could not turn down. So I accepted the load and thought about just making a run for it and try to avoid the old OPP. But decided it is better to not take the chance so I stopped and had the limiter set.

I decided to run and see how it affected the overall performance on my truck. Before I had it set my truck was averaging 9.6 MPH on my Datastar dash read out. All the pro limiter people keep touting how great there tuck runs, great fuel savings and they don't even notice a difference in how the truck operates. Well I am here to report that as soon as I get to a dealer to have it reset, I will be having it reset. Because my fuel mileage, after burning 1000 gallons of fuel with the limit set, has dropped to 9.2 MPH.

So with this in mind if I receive a load going to Canada that pays well enough I will have the limiter set again because with the money I save on fuel I can pay to have it set and reset about 5 times a year. (And I haven't seen 5 good loads a year coming out or going to Canada so I will still be money ahead)

 

[OntarioVanMan]

Thats the thing..every truck is different as is every driver...no one will get the very same results...every truck has its sweet spot..

.04 mpgs is a lot for you....but if too many miles are not involved in limiter mode your loss should be relative to the money going over there...
as long as your compensated for the loss when you negotatiate the price.

 

[TeamCaffee]

How your truck is geared will greatly affect where your "sweet spot" is.

It sounds as if the truck is geared to run at a higher speed.

 

[Crazynuff]

Scott Mooney , the most vocal opponent of speed limiters and organizer of the protests that had disappointing numbers of supporters says his 2000 Volvo gets the best fuel efficiency around 115 km/h , 15 km/h over the speed limit . TheRecord.com - News - Truckers planning rolling protest of speed limiter law . Why does an Ontario based trucker spec a truck to run well over the speed limit ? If Mooney was serious about trucking wouldn't he have replaced his truck 4 or 5 years ago with a more fuel efficient model that would run most economically without violating speed laws ? But I suppose an O/O that spends more time organizing protests than driving couldn't afford payments on a decent truck .
But spec'ing trucks to run at maximum efficiency makes me wonder about the wisdom of management of the major U.S. carriers . When they ordered fleets 3 or 4 years ago didn't they spec them to get the best mpg at 65 m.p.h. ? If so didn't cutting them back a few m.p.h. when fuel prices get higher cause the trucks to run below the rpm of their sweet spot ?

 

[piper1]

I'm sure it has nothing to do with the fuel blend starting to change for the winter or driving attitude.

 

[nightcreacher]

The gearing and speed of your truck has direct effect in your fuel mileage.
Most of the trucks I've had,were geared fast and run slow,this gets the best mileage.
I had a 425 cat with 3.42 gears,13 speed tranny,6mpg running 60 mph,almost 7 running 55mpg
475 cat,15 speed tranny and 3.36 gears,truck was geared to fast,still 6 mpg at 60 mpg,but worst going faster.
550 hp cat,13 speed tranny,3.42 gears.7 mpg at 60 mph,but 7.5 at 55,and 6.5 at 65
Now have 500 Detroit,3.70 gears,10 speed auto shift,truck gets 7 mpg at 60 mph,6.5 at 65.and at 55 mph will get almost 8 mpg,depending on the wind.
Guys that say they get their best mileage at 65 mph,or 70
have no concept at what they are really doing

 

[greg334]

I'm sure it has nothing to do with the fuel blend starting to change for the winter or driving attitude.

Thank you Piper, fuel has more to do with the issue than gearing.

How did gearing get into this anyway?

I have learned that some people act a bit differently with the limiter set on their trucks. Taking a ride with one guy the other day, I set his limiter for him (and his other trucks), when he took me back to my truck, I noticed he was stepping into is a bit more. I asked him about that and he said that the limiter lowers the RPM limit of the engine and had to give him the 15 minute explanation of what really is going on.