Bunny, Portland, Oregon asked:
On a recent trip from the farmers' market with a heavy load of fruit in my bike basket I started to wonder if the placement of the load on the bike makes any difference in the efficiency of the work I do. Would it be easier for me to have baskets on the back where I would pull the load as opposed to on the front where I must push my load. Is it simply too small a system to make a difference?
We put this to Jos Darling, Mechanical Engineering, University of Bath:
Thatís a tricky one, really. The answer is pretty much however you want to do it. If youíre looking at just the rolling resistance the way tires work is that the more weight on the tire the more rolling resistance. What I mean by rolling resistance is how difficult it is to push the wheel forward against the road. As long as you keep the pressure in the tires at a nice high value youíll find they roll very easily. Whether you put the weight on the front or on the back, given itís got to be shared by one or the other, itís not going to make that much odds.
Thatís the simple answer.
But of course, itís never quite that simple. If you look at the finer detail youíve got more complicated things like aerodynamics. If youíve got a basket on the front thatís probably not going to help a whole lot. You might do better to put the luggage on the back where itís hidden behind the rider. The other thing that you might find is that if youíve got all the weight over the front then the front gets a bit wobbly. So rather than cycling in a nice, straight line, youíre going to be wiggling a bit and trying to balance the bike more carefully. In a way thatís going to waste some of your energy like scrubbing off the speed if youíre trying to go round the bend quickly.
In a sense youíd better try and share the weight between the front and the back. The answer is itís not going to make much difference at the end of the day. Unless Bunny is whizzing down hills at enormous hills at speed in Portland I suspect the aerodynamics arenít going to be a big issue. You neednít worry yourself about where you put the weight.
When I was in college, I used to ride many miles back and forth to school carrying books, groceries and other odds and ends. I actually still do a bit of my grocery shopping by bike, and am also an active racing cyclist and scientist, so I may have some experience to throw at this.
As with any means of transport of goods, the weight should be evenly distributed with a bias to the rear axle.
I get my groceries delivered DoctorBeaver, Thu, 23rd Oct 2008
Start pedaling. When you fall over you steer into the fall's direction until you fall the other way and (important!) before you actually have reached the ground. Then you repeat it the other direction.