Join Date: Jul 2009
Location: Silo'd in SD, USA
A simple way to get some measure is to do this:
A small plastic protractor
Some lightweight fishing line
A fishing weight (sinker type, 'bout one ounce)
A black permanent marker (Sharpie works)
A length of wood dowel to span handlebars
Bike on center stand and level.
Cut the dowel so it will span your handlebars with the ends running about an inch over on each side in a spot that leaves the dowel sitting level. each bike is different. Tape the dowel in place.
Find the center of the dowel and mark it with the marker. Center the protractor to the mark with the straight, flat side against the dowel and tape just the ends to the dowel. So far, everything is temporarily in place.
Use the razor blade and cut open the marker. Inside will be the felt material used to flow the markers fluid. Careful, it's messy. Cut a small section appx 1" long and about 1/16" wide from it. This is your new wiper.
Take a length of fishing line and tie a knot to one end of the wiper, wrapping about 3/4" of the remainder a few times and tie another knot at the other end. You should be able to hold the line taught with the wiper in-line with the fishing line. Tie the weight about two inches down from the wiper.
The protractor has a embossed side with raised marks of graduation. Don't use this side, use the smooth side to face you as you sit on the bike. Flip it over if need be. From the center mark, position the wiper at the bottom edge of the arc so that it stays in the middle and tape the fishing line in place. A couple of wraps of the line around the dowel and protracror is a good idea before taping it down.
Now, don't move this thing around too much. Once it's in position it will mark the protractor before you start riding.
Finally, adjust the dowel so that the protracter has about 5 degrees forward (or positive)tilt, giving the bottom about 5 degrees negative (or rearward) tilt and supplying just a bit of constatnt force for the wiper to stay on the plastic. Maybe more depending on your riding style.
Go ride. When done, transfer your off-center marks into degrees of tilt for the ride you just took.
Feel free to improvise the above. Some people (ie: cheap-a$$ed racers) get pretty fancy with the basic above idea. If you plan on doing some testing, use clear celophane tape on the protractor, it'll become reusable and you put the marked tape into a logbook with notation, ...or whatever...
In a cage, some measure of g-force can be calculated using the same set-up with more accuracy than one might expect. Construction technique is key with this idea.