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Old 07-08-2019, 08:09 PM   #155
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Old 07-08-2019, 08:56 PM   #156
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Originally Posted by bucks2 View Post
.
A gasoline engine though, has no such limiter.

A carburetor equipped gas engine , usually had no rev limiter , but modern electronic fuel injected engines do.
My 426 would turn 8,000 + if I missed a shift .
Last two trucks; 5.2l Dakota 5,200 limit, 8.0l V-10 in 3/4 ton Dodge 4,400.
At the limit the computer shuts off every second fuel injector .
Most of the current Hemi powered vehicles from Chrysler won't go over 3,000 RPM unless the vehicle is in motion.
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Old 07-08-2019, 10:57 PM   #157
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Aside from your tires, I'd suggest the two other limiting factors of concern would be the brakes and handling/steering.

Since we rarely drive only in a straight line, just imagine how well your coach would handle doing emergency evasive maneuvers at 108mph? Or even at 88mph? These things are not race cars, and while your coach may be able to reach 108mph that doesn't mean it's safe to do so.

Guessing that you have drum brakes on the drive axle, maybe on the front axle as well. Whether air or hydraulic, your brakes are going to struggle to bring that coach to a safe emergency stop when going 65mph. Can't imagine how much longer the stopping distance would be at 108mph, but I don't want to be the vehicle in front of you having to find out.


Wow. I'll bet you're afraid of all those cars that go 150 miles per hour too. Can you imagine some housewife with all that power? Can her brakes bring her to a safe emergency stop? You know her new Challenger isn't a race car. And while that car can reach 150 mph that doesn't mean its safe to do so. I wonder why all those vehicles aren't piled up in intersections all over America.

I'll also guess you've never driven thru the middle of Nevada or Texas. Places where you can literally see 15 miles in front of you and there are no other vehicles in sight. And no, you're not going to miss that animal that jumps out in front of you at 60 mph either.

How about you give someone the benefit of the doubt as to how fast they should drive and not ASSume they'd do something unsafe? (Who do you know that would travel at 108 in an area with other traffic?) How about we think that maybe the designers of the vehicle made good decisions on what brakes, and steering was needed on any particular vehicle?

I don't know how many people you've taught to drive heavy motorhome sized equipment in your career, or how many times you've driven heavy vehicles thru traffic and down deserted roads with lights and sirens while responding to emergencies. But I know how many I have in my career. I'll put my trust in my ability to drive within the proper limits. I sure hope I'm not in front of you when you exceed your abilities.
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Old 07-08-2019, 11:05 PM   #158
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About the speed rating on all RV tires - They use a letter as required by federal law. The Letter "L' is actually 75 mph max speed rating and this letter is found on the sidewall of the tire. I doubt that your tires are OTR truck tires unless they have been replaced specifically with truck tires. Some people don't know the difference between a truck tire and an RV tire other than the label and it's very simple. RV type tires ride smoother because the sidewall can flex more than a truck tire as well as the RV tire has more carbon black to resist sun damage since the RV is usually parked most of the time. Truck tires are designed to have a longer life, less flex therefore the rough ride since a trucking company is looking for long wear and not the ride.
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Old 07-08-2019, 11:23 PM   #159
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For those that would like to understand the Federal Speed Rating Code I suggest that they get on the internet and go to Tire Rack and they have a list of the speed ratings. Note that 2 or 3 years ago the Fed require all trailer tires to have their speed rating raised from 65 mph to 75 mph. That and a majority of cars on the road have a speed rating letter S that is 87 mph unless it has performance tires that could go over 150 mph or higher if it's a V tire.
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Old 07-09-2019, 05:33 AM   #160
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Wow. I'll bet you're afraid of all those cars that go 150 miles per hour too. Can you imagine some housewife with all that power? Can her brakes bring her to a safe emergency stop? You know her new Challenger isn't a race car. And while that car can reach 150 mph that doesn't mean its safe to do so. I wonder why all those vehicles aren't piled up in intersections all over America.

I'll also guess you've never driven thru the middle of Nevada or Texas. Places where you can literally see 15 miles in front of you and there are no other vehicles in sight. And no, you're not going to miss that animal that jumps out in front of you at 60 mph either.

How about you give someone the benefit of the doubt as to how fast they should drive and not ASSume they'd do something unsafe? (Who do you know that would travel at 108 in an area with other traffic?) How about we think that maybe the designers of the vehicle made good decisions on what brakes, and steering was needed on any particular vehicle?

I don't know how many people you've taught to drive heavy motorhome sized equipment in your career, or how many times you've driven heavy vehicles thru traffic and down deserted roads with lights and sirens while responding to emergencies. But I know how many I have in my career. I'll put my trust in my ability to drive within the proper limits. I sure hope I'm not in front of you when you exceed your abilities.
I'm not talking about the ability of a car to go 150mph here. I'm not talking about the ability of a motor home to go 85mph either. What I'm getting at is the wisdom of doing so considering all the different safety issues involved.

On top of all that, there is the fact that nearly every tire on a motor home is speed rated to 75 mph.

It's not the ability of a car to go 150mph that scares me. It's the idiot that decides to give it a try in the middle of heavy traffic on a crowded highway in downtown Chicago.

I've been driving long enough to know that as speed increases, the ability to safely perform emergency maneuvers decreases. That's not opinion, it's fact.

Doesn't matter to me how many people you've trained to drive. Doesn't matter to me how safe you feel driving a motor home down a busy highway at 108mph. Doesn't matter to me if you have the best brakes and handling equipment possible.

What matters to me is that we're all sharing the same roads, and most of us would prefer everyone do so at a safe speed.
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Old 07-09-2019, 07:27 AM   #161
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About the speed rating on all RV tires - They use a letter as required by federal law. The Letter "L' is actually 75 mph max speed rating and this letter is found on the sidewall of the tire. I doubt that your tires are OTR truck tires unless they have been replaced specifically with truck tires. Some people don't know the difference between a truck tire and an RV tire other than the label and it's very simple. RV type tires ride smoother because the sidewall can flex more than a truck tire as well as the RV tire has more carbon black to resist sun damage since the RV is usually parked most of the time. Truck tires are designed to have a longer life, less flex therefore the rough ride since a trucking company is looking for long wear and not the ride.
I cruise at 64MPH with a 2016 F350 diesel pulling 15,000#. I'm running 1500 - 1600 rpm and getting 10 - 11.5 mpg. No idea what the new dually will get yet. It seems on all my diesel trucks best mpg does not come until 20K are on the odometer.
My Sailun tires have the best reputation of all trailer tires and are rated at 75 mph at 110 psi. Still see no reason to go that fast.
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Old 07-09-2019, 08:15 AM   #162
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I have a 39 ft 2006 Gulfstream on a W24 Workhorse chassis with a Vortec 8.1L gasser. The previous owner installed a full Banks Power system on it. Traveling weight was 23,200 lbs. I also tow a 4500 lbs Jeep Wrangler.
On my last trip, to Montana from Minnesota via I-90, I averaged 7.6 mpg over 2200 miles. I try to keep my speed to about 60 MPH. Nice and easy. But I don't use cruise control too much and try to take advantage of downhill speedups and uphill coasting when I can. This only works on the interstate because I'm sure I would not make many friends if I tried this on a two-lane. Surprisingly, my best leg was from Billings, MT to Buffalo, Wy where I averaged about 9.3 mpg. Tailwinds are your friend.
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Old 07-09-2019, 11:35 AM   #163
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I'm not talking about the ability of a car to go 150mph here. I'm not talking about the ability of a motor home to go 85mph either. What I'm getting at is the wisdom of doing so considering all the different safety issues involved.

On top of all that, there is the fact that nearly every tire on a motor home is speed rated to 75 mph.

It's not the ability of a car to go 150mph that scares me. It's the idiot that decides to give it a try in the middle of heavy traffic on a crowded highway in downtown Chicago.

I've been driving long enough to know that as speed increases, the ability to safely perform emergency maneuvers decreases. That's not opinion, it's fact.

Doesn't matter to me how many people you've trained to drive. Doesn't matter to me how safe you feel driving a motor home down a busy highway at 108mph. Doesn't matter to me if you have the best brakes and handling equipment possible.

What matters to me is that we're all sharing the same roads, and most of us would prefer everyone do so at a safe speed.
I agree with everything you've stated. Unfortunately, I figure you're wasting your breath with bucks and others who feel their equipment and experience are better than everyone else's. They don't seem to realize that even if they did do things perfectly, there are other things outside their control that can cause a problem.

I posted this in another thread. Coming home from Florida, I was doing about 65 in the car when a commercial charter bus passed, I'd say at least 10 mph faster than us. I'm guessing he was about 2 to 3 hundred yards ahead when his front left tire blew. We heard it with windows up and saw the smoke and instant hard swerve to the left it caused. Thankfully there was no one beside him when it occurred. He got the rig straightened, showed he had some experience, but that experience didn't help with the initial unanticipated blowout.

Btw, my 8.1 Workhorse has gotten better than 10 mpg,,, a couple of times during our travels. Most time though, it gets between 8 and 9 mpg.
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Old 07-09-2019, 01:02 PM   #164
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...Coming home from Florida, I was doing about 65 in the car when a commercial charter bus passed, I'd say at least 10 mph faster than us. I'm guessing he was about 2 to 3 hundred yards ahead when his front left tire blew. ...
I would be fairly certain that he was pushing the limits of the tires on that coach - probably had been doing that for some time. That, combined with the heat on the road is not a great combination. Glad to hear that he was able to maintain control, as the stories often don't have a good ending.
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Old 07-09-2019, 01:10 PM   #165
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Old 07-09-2019, 08:28 PM   #166
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Just a couple of photos from my last coach at cruising speed. Second photo is from the trans controller. Could have done more, but the truck cut in front of me, so I had to slam on the brakes.

Some coaches really are race cars, or more specifically designed by race car engineers.

Interestingly, I had a trip where I was cruising well in excess of 80 mph. The coach got 8.24 mpg. On the trip home, I drive at 65 mph, and got 8.5 mpg. I would say the biggest difference is that once you improve an engine's breathing ability, the mileage does not nose dive as bad when the speed goes up. I tend to think for the most part, the exhaust is designed to flow well at the typical cruising speeds. Above those speeds there is not enough free flow, and I believe that is what kills the mileage. Before I installed headers and good mufflers, the mileage used to be very speed sensitive. Once installing the Thorelys and Magnaflows, speed did not seem to impact my mileage near as much.
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Old 07-10-2019, 12:06 AM   #167
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Dodging poky old people is a sign of Road Rage

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For many years I drove the same speed as the 4wheeler traffic and I did that pulling either a 20 ft stacker with one or two cars in it or a heavy utility trailer with a Hummer(H1) on it. 10 years in a 43ft diesel pusher and more recently, a 43 ft truck conversion, 70 to 80 mph. Always had at least two blow outs every trip on the trailers. The runs were always 500 to 1000 miles. Got really fast at flipping on spares but finally said to Hell with that. I reluctantly slowed down to 65, got the highest rated tires I could find, carry 4 spares and no more blowouts. Last trip from S La to Moab, Utah before slowing to 65, three trailer blowouts and a wheel ripped off the hub.
BUT, 60 is TOO slow. If you are in Florida, the average driver is used to dodging poky old people in RVs(yes, I too am very old, but not pokey). Out west you are 20 mph slower than average traffic. I would keep the hazard lights on like truckers do when they are moving slower than expected on the Interstate. Sure you might pinch out a sandwich worth of gas mileage every few hours on the road but I think moving close to the average speed of others is worth a sandwich for safety. Go faster and forget the gas mileage!

ItalGerBrit: By what you say you do, that accounts for ROAD RAGE! If the speed limit is 65 then those driving 85 are what defines dangerous drivers and should not be driving. Driving 60 is the sign of a sane and safe driver that cares about his life, his wife's life and the lives of drivers around him unlike the ones that don't like "dodging poky old people" are DRIVING HAZARDS, not to mention inconsiderate and bad mannered drivers..........
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Old 07-10-2019, 05:00 AM   #168
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Just a couple of photos from my last coach at cruising speed. Second photo is from the trans controller. Could have done more, but the truck cut in front of me, so I had to slam on the brakes.

Some coaches really are race cars, or more specifically designed by race car engineers.

Interestingly, I had a trip where I was cruising well in excess of 80 mph. The coach got 8.24 mpg. On the trip home, I drive at 65 mph, and got 8.5 mpg. I would say the biggest difference is that once you improve an engine's breathing ability, the mileage does not nose dive as bad when the speed goes up. I tend to think for the most part, the exhaust is designed to flow well at the typical cruising speeds. Above those speeds there is not enough free flow, and I believe that is what kills the mileage. Before I installed headers and good mufflers, the mileage used to be very speed sensitive. Once installing the Thorelys and Magnaflows, speed did not seem to impact my mileage near as much.
How are all those improvements in your exhaust system going to help you control that coach in emergency maneuvers and coming to a stop when someone pulls in front of you while you're driving 80+mph?
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