By Mike "Evo" Cannizzaro – J&P Cycles RSC Team

Way back when I saw my first chopper as a small boy, that marvel of mechanical mastery, I knew one day I would build one. One of the first motorcycles I ever owned was a CB350 on a hardtail frame, no brakes, hard to turn and, yes, it had serious rake! I don't exactly know what the rake or trail was at the time. My only concern was how cool it looked, not why it handled like a really long skateboard. I also had a few Kawasakis including a sportbike, but mostly cruisers for me. I currently own several Harleys including a 1977 FXS with a Springer front end. I built this bike piece-by-piece, part-by-part, a true labor of love. Many of the parts on this bike I made myself and with the help of J&P Cycles for things like handlebars, cables, tires, bearings, electrical items, etc., I successfully completed my project!

Mike Canizzaro's "labor of love," his 1977 FXS Springer. 

Before I disassembled my stock bike, one of the first things I thought about was the stance of the bike and how would that affect the handling characteristics. Changing the front end would not only change the look but ride as well. A seemingly easy swap could have had dire consequences (meaning my CB 350!). This was the only thing on this project I got right the first time!

This is where rake and trail come to play. Depending on your bike and style of riding, you will want to know about rake and trail for different reasons. Cruisers and now some touring bike riders want that custom ride to look cool while maintaining the bike's geometry, while sport and adventure riders may want to fine tune their bikes to match their style of riding.

Rake or (castor) references the angle of the steering head or the frame's neck in degrees from vertical.

Trail is the measurement from the vertical line from axle to ground and the distance from the steering head to ground.  

The other dimension to consider will be offset. This is defined as the distance between center-line steering head and center-line fork tubes.  You will also need to know the length of the fork by measuring  from the top of the fork to the axle. The diameter of the wheel you choose will also have an effect, so you will need to know this as well. To find your wheelbase measure from axle to axle or have a look in your repair manual. In some cases, and especially you big wheel bagger folks, help can be as simple as a raked triple tree. In any case, as long as you take into consideration the changes you want to make first or what type of bike you want to build this won't be as hard as it sounds.

To understand how rake and trail work together you will need some inside information. Most cruisers will have 30 to 34 degrees of rake. Sportbikes tend to be around 26 degrees of rake while touring  models fall around 29 degrees. I've seen choppers with as much as 48 degrees. Typically trail is 3 to 6 inches. Anything you do as far as tires, wheels, and suspension will affect these measurements. Even doing a wide tire may require some front-end adjustment.

An angle finder will help find rake. To find your starting point, first stand the bike upright. If it has rear suspension have someone sit on it. Draw a vertical line from the axle to the ground. Second, draw a line following the steering head to the ground while being cognizant of the offset. You should be in front of the axle; measure one mark to the other. At too little or negative trail the bike will handle very well at low speed but becomes very dangerous and unstable at high speed. Fear the death wobble! If the trail is over 6 inches the bike will become clumsy and feel sluggish at high speed.  You’ll have trouble balancing at low speed or on winding roads. These are just a few things to think about before you start that project. If you are  building a bike's chassis from scratch and your trigonometry skills are not  up to snuff, there are plenty of rake and trail calculators online to help you.

Dialed! 

Building or customizing your own bike gives you that sense of pride and feeling of accomplishment. I find knowledge of your bike always help. I always keep a good supply of maintenance items like spark plugs, oil & filter and even some gaskets. It may sound odd and I know you're thinking, what does that have to do with rake and trail? Well, you would be right, nothing! But the better you know your own bike the easier it is to make it the way you want! So, let's go build something. Take your time, get'er done and get'er right!