[Joshua]

First of all, after a 4500 mile trip in my Corvette from Knoxville to Pahrump NV and back I tried to maintain 10 over the speed limit. In only two instances I was passed by a truck and that was when I was doing 75. When trucks were blocking my lane because they were passing other trucks I rarely was able to even maintain 70, with most trucks blocking my lane while passing doing between 65 and 70. Most of my trip the speed limits were 70 to 80 meaning I was trying to maintain 80 to 90.

So if you are intimidated by trucks my advice is to give them a mental finger and drive your comfortable speed.

Now lets talk about reality. Your tires have a speed rating. Find out what it is for your specific tires and do not exceed that speed. A fact of life is driving fast is something anyone can do. Your bus will drive much faster than almost all traffic on the road, topping out around 85 if it has not been modified. It is not about driving fast. It is about stopping.

The average car on the road is going to stop from 60 MPH somewhere around 110 to 120 feet. Your bus is going to stop from the same speed around 280 feet. If you want to go fast, at 70 your stopping distance increases to 450 feet. If I was all alone on the highway and never had fools pull in too close, or never was at risk of having to make a quick stop 70 would be a nice speed. But that is not likely.

The car that pulls into close, the car that decides at the last minute to get off at the exit and slams on the brakes in front of you, the car that has an unexpected stop, such as hitting an animal is a threat and the faster you drive the more likely if you are lucky you get to change your shorts, and if you are unlucky metal gets bent.

I admit I take a lot of heat for driving at 62 MPH. I don’t care. I set the cruise, let the world pass me by, and rarely have to slam on my brakes or make a lane change so for me driving the bus is total relaxation. What speed you should drive is up to you, and you alone. But at least be informed and understand the impact speed is going to have on your driving habits and safety.

[Marshall]

Thanks Jon, sage advice as always.

[Dick]

Like Jon, I do 68 in either the right lane or the middle lane. Most of the time, I’m in the right lane, nestled in a chain of other trucks doing the same speed. I’m not opposed to speeding up to 75 or more to negotiate traffic, but my cruise is set to 68.

[Chad]

Larry,

in addition to Jon’s advise, I will share with you my experience for consideration. When I first got my bus I drove her 75 – 80+ left lane all the way. That was up until I blew a steer tire doing 80 and if it wasn’t for having an early career driving trucks, where 2 things are instilled in my DNA, never wrap my thumbs around the steering wheel and never ever jump on the brakes when a tire goes, as well as the grace of God, I was able to keep the dirty side down and safely stop.

Bottom line is the unexpected happens. Always position yourself to be able to handle the unexpected. I now drive in the low to mid 60s. If those around me on the road don’t like it, I just smile at them because I am driving a Prevo and they are not. When I have to get somewhere in a hurry, I fly, otherwise I relax and enjoy the open road

Safe Travels

Alex

---

1984 96" with 8V92TA

(remodeled Liberty Coach)

Greenwood, MO

[al]

If I recall, the speed rating for Michelin is 65 mph.

[Pat]

Power torque curve on a 60 series is 1500 Rpm’s. That works out to approximately 63-65 MPH on most Prevost’s coaches.
63-65 MPH = safest speed and most efficient use of engine power.

My 2 cents for what it’s worth.
Chuck

[Bill]

Michelin’s are rated for 75 MPH.

To the OP, the acceptable speed for your towed is determined by the vehicle manufacturer. I tow a Jeep and it does not have a towing speed limit. I cruise very comfortably at the speed limit (plus a couple) to a max of 72-73 as that’s my comfort range. The bus runs quite smooth even at 80 when heading down a hill that’s a bit steeper than I had expected. Of course speed depends upon traffic but when I’m out there on the Interstate with limited traffic my goal is the destination so the speed limit works for me other than the 75 and 80 speed limits out West.

---

2005 XL Thompson Coach

Rarely tow anything behind us.

Sold: 1993 Liberty that we loved for 12 years.

[Fred F.]

On interstate system I run at 63 mph. I may hit 65, 67 going down a hall, but I keep an extreme watch on it. I am with Jon, and others that have stated, relax and cruise. Vehcile wants by they will find a way.

R

[John]

Thank you all for your replies.

[Larry]

Chuck, thanks for your response. I think early on I asked what the best rpm for the Detroit Series 60 was to get the best fuel economy and got some answers like “if you’re worried about fuel economy, you’re driving the wrong vehicle” and the like. That was fine cause we like to have a good laugh but I know all engines have a sweet spot where they operate the most efficiently so thanks for shedding some light on that topic for me. ;^)

[glen]

Actually, max torque for the Series 60 is at 1200 rpm. The torque stays constant from 1200-1400 rpm for the 12.7l and 1200-1500 rpm for the 14l version. Driving anywhere in the 1200-1400 (1500) rpm band would be fairly efficient. 1200 rpms would be most efficient due to lower internal friction. But that would be pretty slow.

[Pat]

Great info, I have been looking for the torque and power chart for 12.7 liter 500 HP.

Larry Nelson

2002 XLII Vision

2019 BUICK Invision

Hurricane, Utah

[Jimmy]

Threegreens:

I second Larry’s comment, have not seen that chart before.

Thanks for the posting

Chuck

[Tim]

I am far from an expert but based on a sense I get about how the engine feels as it pulls I found in my 8V92 the “sweet spot” was 1800 RPM. Below 1500 the 8V92 just seemed to get lazy, likely related to that engine just not getting enough turbo boost.

On both my 12.7 and 14 Series 60 engines 1500 RPM seemed just right with the right combination of power, wind noise, fuel economy and reduction of downshifts lower RPM would cause.

That RPM in both coaches was 62 MPH.

At around 4 mph per 100 RPM stepping up to 1600 RPM pushes the speed up just enough to make me have to change lanes due to slower traffic often enough my lazy attitude found driving was far more relaxing and easy if almost everyone was passing me. I rarely had to touch the brakes or turn off the cruise control at 1500.

Having said 1500 I know despite what the torque curves show, 1500 is not ideal for hill climbs so in anticipation of a hill that will require a downshift, I drop down to 5th manually, increase my speed, and switch to performance mode so the transmission will hold higher RPM longer on upshifts, and drop a gear sooner on downshifts. I do that so I can spend time in the fast lane passing trucks going slow up the hill.

[Ed]

I cruise around 1450-1500 rpms (60-65 mph) too. Still very close to max torque and lets you hang with the trucks (at least on the West Coast). I get about 7 mpg towing a Jeep Wrangler over 3000 miles of varied terrain.

The main thing I take away from the charts is, don’t be afraid of full throttle below 1500 rpm. You are not lugging the engine.