I recall a similar question being on the air, but here I go: I’m a cheapskate and brake and accelerate easily, but here’s MY question.
My vehicle is a 1999 Ranger, 4X4, 5-speed. From a fixed point, I can take two routes to get home. The shorter route is 1.9 miles, up a very steep hill (450 feet climb in one mile). I can get it up to 4th at the bottom of the hill and try to get some speed up, but halfway up I always have to downshift to third, at a high RPM, AND if I get behind a truck or slower car, I may even have to downshift to second to get to the top. I can avoid the steep incline by taking a route that is 4.9 miles, but it’s a very gentle slope and I can make the whole uphill run in fifth gear without lugging. I get about 21 on the highway, so this will cost me about 1/4 gallon of gas. I’m sure the longer route sames me money on gas as well as wear and tear on the truck. What do YOU think?
yes, I always try to follow the route of least resistance and coast to red lights and such. it saves fuel and wear and tear. sometimes it even saves time to take a much longer route
I’m not sure how a mile long hill going up 450 is a big deal. You cut three miles off the trip. The car doesn’t really care if you are running in a lower gear at a higher rpm as long as you aren’t lugging the engine. I’d take the shorter route if it was more fun. Sometimes I took the longer or scenic route home just because it was different.
Why would you drive 3 miles out of your way to avoid an 8% grade? That’s a pretty average hill–nothing earth-shattering. There’s no way I waste the time to coddle my truck: it serves me, not vice/versa. (More to the point, it would take extremely careful planning to even devise routes that had no 8% grades around here.)
Going uphill if you downshift correctly and at the right time, there shouldn’t be a big increase in the Ranger’s RPMs, so that really shouldn’t be an issue. Also, as Bing wrote, as long as your gears aren’t lugging, it’s not an issue to be concerned about.
First, it’s closer to 10 % because it crowns maybe 500 feet before I turn. Secondly, i haven’t measured MPG at all. I get 21 on the highway, maybe 22. I’m sure not getting close to that lugging in third. Thirdly, the age of the truck shouldn’t matter. It’s well maintained with 55,000 miles on it since i bought it new.
If you get 21 mpg on the long road, you use slightly less than a quarter of a gallon of gas. To use the same amount of gas on the 1.0 mile route, you would only get a hair over 8 mpg. I’d take the shorter route.
I don’t think there is any way to extrapolate your highway mileage to the short distance uphill you travel. I don’t think driving up an incline for less than 2 miles amounts to any kind of wear and tear on the car. I think the fuel savings will be in the pennies, therefore irrelevant.
Take the route that takes less time. When you’re dying, will you be wishing for more time or more gas money?
8% 10%…still pretty average. I probably drive a 10% 3X/week, and a 14% weekly (used to be daily, before I moved).
I guess it’s regional…you flat-out would have to carefully route-plan to avoid those sorts of hills around here: take only roads that parallel railroads or rivers, or interstate-quality roads. Perhaps, in west Texas or Florida, 8% might well stand out.
Heck, even bicycles around here do steeper. We have the "Dirty Dozen"race annually, with the 13 steepest hills in the Pittsburgh metro area, the flattest of which measures 20%. (The steepest, Canton Ave, is 37%, cobblestoned, and arguably the steepest paved road in the world.) The road in question wouldn’t even make the short list!
I was referring to simply filling the tank, note the odometer, and drive one way long enough to use, say, a quarter tank. Then refill your tank, note the odometer, then calculate mpg (miles traveled/gallons to fill the tank). Then drive the other way and use a quarter tank, refill the tank, note the odometer, then calculate mpg the same way. This assumes you can devote this vehicle to this purpose, but as Click and Clack would say, “It must be done to advance science!”
@insightful: Use a quarter tank on a one-mile hill? What…go up and down it 60 times in quick succession?
Actually, if OP is interested in maximizing fuel economy and wear and tear, he should go UP the steep hill and DOWN the gradual one. Going up, he should be going slower, less aero drag, and almost all the gas burned gets stored as potential energy (by raising the 4400# truck up a 550’ hill). If he stays out of open loop, he’d be running the engine at peak BSFC.
By going down the gradual hill, he can coast (heck, in neutral if it’s legal/deemed safe in his location) with minimal braking. Going down the steep hill would be less efficient as it would require braking, “wasting” all the built-up potential energy as heat.
OK, an eighth of a tank. My test would cover repeated trips over a couple weeks, but it must be done for the sake of science. I’m also assuming (that word again) that these routes are taken every day, like to work. If they’re only taken once a month, then yeah, the whole conversation is moot. I still say if you get 20 mpg on the long route, you’ll get at least 10 mpg on the short route.
I’m sorry, I just can’t help myself. This reminded me of when I was a kid maybe 12 or 13. My Mom and I would take the car out to the gas station at night to get gas for my Dad’s commute the next day. The question was always if we should come back the long way or short way. The short way meant straight home, but the long way went through the fairgrounds where I’d hop on the Sears catalog and drive. That’s where I learned to drive a manual in 1961.
I’m in agreement with meanjoe, going up the short route will get worse mpg, but will use less fuel than the long route. Both routes lift the weight of the vehicle the same height, but to use the long route, you also add a couple of miles of rolling resistance and wind drag to the energy needed.
If I was trying to set a gas mileage record, I would choose a road with short steep climbs followed by gentle gradual descents allowing me to safely coast with the engine shut off during the downhills and the climbs putting enough load on the engine to get it to run at its peak brake specific fuel consumption.
OK, i see there’s no gas saving. I still prefer the long way because it’s easier on ME. If I have a load in the bed it’s a no-brainer. FWIW, all my neighbors take the longer route when there’s any snow on the roads. I didn’t mention that there’s a dangerous interstate highway exit at the crest, with no traffic lights, and at rush hour, the hill can be blocked solid in both directions.