After a ride last month, a number of us were talking about ride costs and one mentioned her "$300 T-shirt" that she was getting at the awards meeting. This being Texas, it was immediately christened the "Neiman Marcus T-shirt." It was indeed a nice T-shirt and our discussion led to the topic for this column: how to keep the cost of attending rides down when the price of diesel is at or more than $4 a gallon everywhere in the country.

When I looked at the breakdown of my costs for that ride, 75% was fuel cost. The ride entry was 20% or less of my ride expense. Most of my rides are 300 miles or more one-way so I've been looking at ways to reduce my fuel costs since fuel reached $2.50 a gallon. Pulling a living quarters trailer or even a bumper-pull significantly reduces my mileage because of the air resistance of the flat surfaces of my truck/trailer and the increased weight pulled.

The greatest single factor in fuel economy is how fast you drive. This is more important for the vehicles we go to rides in than it is for our more streamlined family car because aerodynamic drag forces go up exponentially with vehicle speed. Above is a sample plot of the miles per gallon for a large vehicle like ours.

Car manufacturers give the highway mileage of new cars at the peak of this curve which is about 47 mph. Most of us are driving at the upper speed portion of this curve on our way to rides. From the graph, we see that driving 65 mph rather than 60 costs 40 cents per gallon more. Driving 75 mph rather than 60 mph costs $1 per gallon more. Diesel engine fuel economy is a little more critical than gasoline engines on speed but the principle applies to both types of engines.

Truckers have been impacted significantly and are taking steps to conserve fuel by reducing speed. Con-Way Freight, one of the nation's largest trucking firms with 8,500 rigs, has announced it is turning back the electronic speed limiters in its entire fleet from 65 miles per hour to 62 mph.

One of our Northeast members commented in a recent e-mail that "my brother, a professional trucker, and his friends have all reduced their speed from 70 mph (highway) to 58-63 mph, and he is saving over $400 per week in fuel costs . . . just by reducing his speed . . ."

There's a trade-off in that it takes longer to get there at 60 mph than it does at 75 mpg. On my typical drive to a ride, the difference in time once I include stops is about 45 minutes. I've compromised and usually try to keep at or below 65 mph which still provides a substantial saving. If you have more time, then slower speeds will do even better although too slow becomes a problem for other traffic.

There are a number of other things we can do to improve fuel economy: proper tire inflation, a tune-up for your engine and clean air/fuel filters are among them. Pooling with another rider is certainly a way to reduce costs and enjoy some company on the drive. Attending more multi-day rides helps a lot on the cost per day of riding. Ride managers are offering more multi-day rides in response to higher costs. (For more on this topic, see Ride Managers' Forum.)

I enjoy going to rides but need to keep my costs down. Simply driving slower is one of the best ways to do this so that all of us can enjoy our sport, keep our costs down, and stay safer on the highway.