I am sometimes amazed how fast some people drive their RV.
Take a road trip in your car on the open interstate and it is pretty common to drive around 80mph or so. But, it sometimes amazes me when I am seeing motorhomes going almost the same speed.
Or worse… driving that fast with a towable.
I know we live in a fast-paced world. I know it is made worse by social media, video games, and other things that give people short attention spans. If you’re new to RVing, you may think it isn’t much different than driving a car. If the cars and big semi trucks are cruising along at 70-80mph, why should it be any different for you?
But, slow down.
Let’s discuss why…
Mind Your Tire Speed Ratings
First off, consider that the tires on your RV are rated up to a certain speed. If you surpass that speed, you are at a higher risk of a tire blowing out. Then, things like this can happen…
Towable trailers seem to be at higher risk here. Often, these trailers are equipped with cheap Chinese tires (sometimes called “china bombs”). When you combine that with the side-to-side motion of trailers… plus the fact that trailers with 2 axles often drag one of those axles sideways when taking a turn… these trailers often blow their tires faster than motorhomes.
It can cause a lot of body damage when a tire blows. It isn’t something you want to deal with.
Motorhome tires are often rated a bit better. But, it is important to know the speed rating of your RV tires.
Most motorhome tires are rated for speeds up to 75MPH. You can check your tires by looking at the sidewall and looking for the letter designation for speed. You’ll find letters ranging from L to Z and this signifies the speed rating of the tire. Most motorhome tires have an “L” designation, indicating 75MPH rating.
Image source: Utires.com
Obviously, you’d need to check your own tires to see what their top speed rating is. It is also really important that you keep your air pressures where they need to be.
Just because a tire is rated up to a certain maximum speed doesn’t mean you should drive that fast, however. Let’s continue…
Effects on Gas Mileage
Your RV is about as aerodynamic as a washer machine.
When you’re driving that RV down the interstate, it is pushing a lot of air. It is running head on into a big pile of air the entire time. And unlike a car, it doesn’t gracefully glide over the body. Your RV is running into it directly and just pushing through it.
On top of the air, your RV is obviously heavy. So, it takes a lot of engine power to move that box down the road. The faster you are going, the more power it takes.
But, how much more does the engine have to work depending on your speed? Is it nice and linear?
Answer = no.
The amount of drag on the body of your motorhome goes up by the square of the speed increase. So, if you double the speed, the force goes up 4X. If you triple the speed, the force goes up 9X.
So, every bit of speed you demand of your motorhome means there is much more counter-force on the front. This takes more power to overcome and decreases effeciency. And the amount of force goes up much faster than increase in your speed.
When the engine needs to work harder, it means it takes more gas. Obviously.
Safety Issues That Come With Higher Speeds
When you are bookin’ down the road at 75-80mph in an RV, you are quite literally at higher risk. You are relying on “lady luck” that nothing goes wrong.
First off, if a tire blows, you are at higher risk of losing control of the vehicle. Just go Google around for pictures of motorhomes that end up in the ditch… or towable trailers that have flipped. It isn’t too hard to find.
Secondly, the speed means that it takes a longer distance for you to bring it to a stop. You cannot control what the people around you in their cars are doing. It is not uncommon at all for things to slow to a crawl on an interstate and people hit their brakes. Sometimes, if they didn’t notice because they had their head up their butt, they’ll suddently slam on their brakes.
Then, there YOU are bookin’ with YOUR head up your butt at 70-80mph in a freakin’ HOUSE on wheels and you’re left trying to bring that beast to a VERY fast stop. If you didn’t calculate that one correctly or simply don’t have the room, you go crashing into things.
Your Ideal Driving Speed Is…
I personally drive my motorhome at a speed of about 65MPH. I just set the cruise and let it go.
Most people “in the know” on this recommend driving between 60mph and 65 mph.
If you’re driving a towable, you may want to go ever slower. Trailers are often at a higher risk of tire blowout or wagging issues (especially if not hooked up correctly).
Many times, you will see the big diesel Class A rigs driving faster. It is easier to do because they are quieter in the cockpit and the engines have more torque. So, it is easy to get out there and drive like a road bus when you are in a diesel rig. You are likely safer doing so than in a gas-powered rig just because you’re on bigger tires and a bus chassis. But, it doesn’t mean you SHOULD be driving that fast for the above reasons.
Now, even if you’re driving between 60mph and 65mph, it doesn’t mean if you go any faster than that for a minute that you’re taking your life in your hands. I’ve had my rig up to 70-72 before while passing somebody or going downhill. But, I try to keep it at bay.
I’ve never had my rig up to 75 or 80mph. I just won’t do it.
And honestly, I cringe every time I see somebody driving their RV at 80mph trying to keep up with cars. It is just… stupid.
In the end…
We Didn’t Buy An RV To Be In A Hurry
RVing isn’t a way to get there fast. You’re supposed to enjoy the journey as much as the destination. And, we’re not trucker drivers who are driving on a schedule.
So, slow down.
Set the cruise and relax.
Let the cars and big trucks pass you by.
Get better gas mileage. Stop increasing your risk of tire blowouts (or worse).
You are driving your HOUSE. Don’t forget that.
And these things are not built for constant road travel like a commercial semi truck. So, stop trying to act like that. 🙂