Suppose I wanted to drive an automobile in reverse gear from Boston to New York. Is there any mechanical reason I couldn’t? What would be my top speed? (assuming a completely stock passenger car - a Honda Civic for example).
Reverse is geared very low and any time you drive in a lower gear than necessary it does put stress on the transmission. However, if you were to drive very, very slow, say two miles an hour, you could probably do it, however finding a highway that would let you would be something else again.
What happened? Trying to erase some miles that shouldn’t be on the odometer?
Castor/caster effect would keep your already gear-limited top speed down unless your full attention was paid to steering (and I’m talking much moreso than driving a car forwards - one inattentive moment over an hours long drive could see you spun out. Aside from that, just the limitation of driving in a very low gear - you would theoretically be fine at very low speeds, but it’ll be hard to stick to that without the temptation to put the foot down.
Is this a Frank Drebin sort of thing?
Actually, I was thumbing through an old book last nght and came across a column by Erma Bombeck that someone must have enjoyed and cut from the paper. For those of you who don’t know or remember, she was a syndicated columnist who wrote about the everyday trials and tribulations of raising kids and living in suburbia. Shed died of cancer several years back. Anyway, the column dealt with taking a long car trip with a bunch of kids and having to listen to them argue about whether you could drive a car in reverse from Boston to Los Angeles. She also wondered in the column what the proper dosage for a sedative wouuld be.
When we were in high school my brother had an old (1977 or something) Mercury Capri – it would have been close to 10 years old at the time of this incident. He was driving in another town about 10 miles away when something happend to the transmission and the car would only go in reverse. So, with my dad following him in another car, my brother drove the Capri all the way home in reverse, looking over his shoulder to steer. He got stuck once at a curb and they had to get out and push the car clear.
He mostly took back roads, and he said the only scary part was crossing Rte 1 (a busy four-lane road) without benefit of a stoplight.
Looking back now, it seems like that wasn’t a very good idea.
“Don’t make me turn this car around!”
Your neck will get very tired.
The transmission pretty much won’t care. The stresses on the tranny will be very low as the gearing is very low.
The engine won’t care EXCEPT there will be no ram air effect for cooling, so the radiator fans will have to run all the time. (normally on the freeway, the fans don’t run as there is enough air flowing through the radiator without them.
The caster on the steering will be all wrong, but I don’t think that is as important as you will now have rear wheel steer, so any steering inputs are magnified. At say 20 mph backward a tiny input will make a huge change in your direction.
Your top speed? I don’t know, it would depend on how your car is geared, probably in the 15-20 mph range.
I am told that a DAF had a belt driven continuously variable transmission and would go as fast backwards as it would forward. I did not find a cite for this, just something I heard.
I had a demo derby car built just for racing in reverse. We did a few changes that made the car much easier to drive. The first thing was to flip the rear end over. This way the transmission could be put in drive and allowed for the same speed as a regular car. Next we swapped the brake proportioning valve to fix the problem with rear tire braking. Last, a bucket seat was installed at about a 45 degree angle to save wear and tear on the neck. This car was capable of lap times close to what other demo derby cars could do running forward.
This statement has a very specific meaning in my house. I now have to clean applesauce off my keyboard.
Thanks.
Reverse gear ratio is effectively first gear backwards. Your top speed will be pretty close to whatever you can do in first gear driving forward. Or Low One if it’s an automatic.
IIRC somebody did this a few years ago.
Steering is unstable in reverse - the car tends to turn more tightly if you let go of the steering wheel, the opposite of how it works going forward. So you’d have to provide a great deal of positive stability mentally to overcome this. Rick alludes to this, and also correctly points out the radiator air flow wouldn’t behave as intended. Ditto for breathing exhaust fumes, I guess. Also, the mass of your lower leg on the acellerator pedal makes that system unstable too, so when you press the pedal you’re thrown forward which makes you press the pedal further, etc. The brake, for which this is normally true, would now stop acting that way.
Once upon a time, drum brakes were designed so that the tangental force acting on brake shoes would also increase the perpendicular loading force. This had an effect sort of like power brakes. If you turn this inside out, you’d have an effect like the multiple wraps of rope on a ship’s capstain constricting and gripping it to multiply the tension. Going in reverse, all this works against you. I guess power disk brakes have none of this, though.
Transmissions might well not be designed to handle much wear in reverse. Said another way, if you could put many thousands of miles on a transmission in reverse, they probably wasted money designing and building it.
'Splain please?
I believe what he means is that he removed the rear differential and re installed it upside down, and not that he removed the back half of the car and flipped it over [wheels to the sky].
Not quite on-topic, but close enough that I’ll just fire it out: The other day I was going through a fast food drive-thru, and the guy two cars ahead of me went through the line in reverse. It was obvious to me that he and his passengers were just a bunch of college age kids who thought it was pretty funny (probably knew the servers too). I thought it was hilarious.
I seem to recall a spec sheet for a VW bug in the 60’s that gave the design life expectancy of each gear. Reverse was only designed for a few hours of cumulative time, which seemed low until I calculated that the number of hours you normally spend in that gear isn’t really that much. So using it as the only gear for 3000 continuous miles might exceed the design parameters.
Or even 300.
So sorry for this hijack, but does that really work? I thought it was an urban legend kind of thing.
No, Ferris, this does not work. 
Safety would be my main concern.
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If your driving an unmodified car, your making the trip at a speed generally lower than most roadways. (Top speed would be 20 or 30 MPH, I assume.) A lot of the state routes (let alone the interstate) have a typical speed of 45-55. So your a slow moving obstacle for the other traffic to deal with.
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Your car is facing the wrong way. This manifests itself several ways:
2a) Other folks will initially be confused as to your intentions. Multiply this over the thousands of drivers you will cross paths with on the roads, and I would not be surprised if the odds of an accident are very high.
2b) Steering based on the tires in the rear of the vehicle is a bit different than the follow-the-leader front wheel steering we are used to. Fork lift drivers and boat handlers can attest to this.
2c) Your first instinct in an unexpected situation may be the wrong one, as with you looking over your shoulder and steering that way, you may steer opposite what you wanted to.
2d) Neck and back fatigue. Done over a few hours, a regular person will suffer cramps and head aches.
- I do not know if their are moving violations potentially involved here… operating a car in reverse on the freeway is a no-no in some locations.
Bah! James Hargis and Charles Creighton went from New York to Los Angeles driving backwards in 1930. It took them 42 days.