Community Forums

PlayItForwrd · 09-01-2015, 12:47 PM

at 65 mph you're moving at 95 feet per second.
at 80 mph your moving at 115 feet per second.

If you have to panic stop 26,000 pounds of motorhome, that 20' per second isn't going to make much difference. The trick is, stay alert to your surroundings and, extreme circumstances notwithstanding, you'll never have to panic stop.

I pulled our 7000# boat with the cruise set at 72mph for the better part of 200 miles last weekend, and I was the slowest vehicle on the road. That said, know this: If you're driving 55mph on a highway where everyone else is driving 80, you're the most likely vehicle to create an accident...

BeachDude · 09-01-2015, 12:58 PM

Quote:

Originally Posted by PlayItForwrd

....That said, know this: If you're driving 55mph on a highway where everyone else is driving 80, you're the most likely vehicle to create an accident...

+1, Absolutely agree!

dennis45 · 09-01-2015, 01:35 PM

I don't have a problem following traffic at whatever the flow is be it 50 to 65. I won't drive 75-80 no matter what.
The part that really bugs me and I see all the time, is drivers who slow down and speed up. Pick a speed and go with it. These are the ones who cause accidents.

LVRVLUVR · 09-01-2015, 02:25 PM

Quote:

Originally Posted by PlayItForwrd

at 65 mph you're moving at 95 feet per second.
at 80 mph your moving at 115 feet per second.

If you have to panic stop 26,000 pounds of motorhome, that 20' per second isn't going to make much difference. The trick is, stay alert to your surroundings and, extreme circumstances notwithstanding, you'll never have to panic stop.

I pulled our 7000# boat with the cruise set at 72mph for the better part of 200 miles last weekend, and I was the slowest vehicle on the road. That said, know this: If you're driving 55mph on a highway where everyone else is driving 80, you're the most likely vehicle to create an accident...

x2

LVRVLUVR · 09-01-2015, 02:29 PM

Quote:

Originally Posted by GRUU

What's your hurry?

had a hot dinner and a piece of pie waiting at home...

wanted to get there before they cooled off..

actually ,... just wanted to see what it would do..

LVRVLUVR · 09-01-2015, 02:32 PM

Quote:

Originally Posted by BeachDude

Yeah, next time I take out my coach in CA, (with a 55 mph limit when pulling the toad), I'll pull out my iPhone while I'm going over 80 mph to satisfy your doubt.

I'll get right on it.

serious,,, will yours run 80 on the speedo.... none of my fords would go over 75 with out shutting off...

docj · 09-01-2015, 02:41 PM

Quote:

Originally Posted by PlayItForwrd

at 65 mph you're moving at 95 feet per second.
at 80 mph your moving at 115 feet per second.

If you have to panic stop 26,000 pounds of motorhome, that 20' per second isn't going to make much difference.

Actually, it will make a world of difference. At 80 mph your rig has 46% more kinetic energy than it does at 65 mph (because KE is proportional to the square of velocity) and kinetic energy is what has to be dissipated in order for it to stop. Your brakes will have to work much harder to bring you to a stop and your stopping distance will be far greater.

I don't care what speed you drive at, but everyone has to deal with the same principles of physics.

LVRVLUVR · 09-01-2015, 03:16 PM

Quote:

Originally Posted by docj

Actually, it will make a world of difference. At 80 mph your rig has 46% more kinetic energy than it does at 65 mph (because KE is proportional to the square of velocity) and kinetic energy is what has to be dissipated in order for it to stop. Your brakes will have to work much harder to bring you to a stop and your stopping distance will be far greater.

I don't care what speed you drive at, but everyone has to deal with the same principles of physics.

don't forget going up a 6% grade vs down a 6% grade

Gordon Dewald · 09-01-2015, 03:43 PM

Actually speed is not what kills or maims. It is the sudden stop that causes the damage. If you have a blow out and drive into the ditch at 80 you could gradually reduce speed for for miles (assuming you keep control of the unit) and be OK as long as there was not a culvert, trees or other obstacle in your way.

PlayItForwrd · 09-01-2015, 04:55 PM

I understand kinetic energy and all that. Here's a simpler version of what I meant:

Suppose some car on the side of the road pulls into your lane 200' in front of you... based on typical reaction times, at 65mph you'll travel 145' before you can even hit the brakes. At 80mph, you'll go travel 175' before hitting the brakes... In 'kinetic' terms, yes, it's a world of difference. In 'reality' terms, the end result of a 26,000# motorhome smashing into a parked car at 55 mph or 70 mph won't be a whole lot different.
I don't advocate driving motorhome's 80 mph, mostly because there may be a loose nut holding the steering wheel.

-- but IMO it's not inherently unsafe to do so.

Possum · 09-01-2015, 05:08 PM

To put it another way would you want to be in and around traffic that has a guy (girl) white knuckling the whole way or be in and around traffic where you can left lane past the guy relaxing and driving comfortably and assured of his abilities.

I have driven long haul and did the limits and then some; now I don't have to be anywhere in any hurry.

docj · 09-01-2015, 05:11 PM

Quote:

Originally Posted by PlayItForwrd

I don't advocate driving motorhome's 80 mph, mostly because there may be a loose nut holding the steering wheel.

-- but IMO it's not inherently unsafe to do so.

Since most, if not all, MH Class A tires are rated for 75 mph, I would contend that it is inherently unsafe to drive above the speed rating of your tires. JMO.

Gordon Dewald · 09-01-2015, 05:14 PM

Quote:

Originally Posted by Possum

To put it another way would you want to be in and around traffic that has a guy (girl) white knuckling the whole way or be in and around traffic where you can left lane past the guy relaxing and driving comfortably and assured of his abilities.

I have driven long haul and did the limits and then some; now I don't have to be anywhere in any hurry.

One of the issues is the person who claims they are safer and more competent at 80 mph than at 60 mph. Something to do with living on the edge keeping them on their toes while slower speeds lets them relax and possibly falling asleep.

Either has to be testosterone or adrenaline.

Steve Ownby · 09-01-2015, 05:22 PM

Quote:

Originally Posted by Gordon Dewald

One of the issues is the person who claims they are safer and more competent at 80 mph than at 60 mph. Something to do with living on the edge keeping them on their toes while slower speeds lets them relax and possibly falling asleep.

Either has to be testosterone or adrenaline.

The amount of chest thumping and juvenile posturing in this thread sounds more like a bunch of teens in the 1950-60 than supposed competent drivers of vehicles weighing between 20-50,000 pounds. I hope to never meet a few of you on the road.

Steve Ownby
Full time since '07