Rake and Trail

One of the things that gives choppers their cool look is a raked out front end. The rake is the angle of the front fork from the body. Think of it this way... if you draw a line directly down from the top of the frame to the ground perfectly perpendicularly this is the 90 degree angle of your right triangle. From where that line (or plane) hits the ground to the spot beneath the front wheel is the second side of your right triangle. The line that goes from the top of the frame to the wheel is your hypotenuse.

So before I knew what kind of front end I needed to buy and what size to get we had to figure out what the rake was on the current frame. If a chopper has a front end that is too long the bike (or trike) won't be able to make a U-Turn. Those of you with big cars with a crummy turning radius can relate to that.

Now there is physics and trigonometry involved in the front end rake of a chopper. Due to the pressure of the vehicle and the resistance of the ground the front wheel wants to spin not round and round north to south but round and round horizontally. For a chopper to be safe the physics must be right so that at both low speeds and high speeds the front wheel does not have too much side to side wobble, nor does the bike (or trike) have the propensity to try and flip ass over front end.

Years of practice, and eventual mathematical computation has taught chopper builders that the ideal rake is between 30-45 degrees. Old bikes where the rider sat upright had a smaller degree of rake on the front end. New high speed "crotch rocket" motorcycles often times have less than 28 dgrees of rake on the front end. The typical Harley Davidson motorcycle has between 28-32 degrees of rake.

C gets out his old school engineering tool, the plumb bob, and hangs it from the neck of the trike frame. I stick a piece of doweling in the neck for visual effect.

As the plumb bob hangs perfectly perpendicular to the ground due to gravity we have the back leg of our right triangle. Based on the readings we learn that this trike frame has a front end rake of 53 degrees. That is too much. We will have to adjust the rake.

However, making a chopper safe to ride involves more than just what angle the front end rakes out from the frame. I can use a right triangle calculator (because I suck at math) to figure out how long a front end to order, but we also have to worry about the trail.

Trail is the horizontal distance from where the steering axis hits the ground (our perpendicular line) to where the front wheel hits the ground. The trail is calculated in inches. The greater the amount of trail the more stable the front wheel is but it also makes the wheel harder to control. If the trail is too small (or negative) the chopper will have little to no wobble at low speeds, but be difficult to handle at high speeds. If the trail is too great the chopper will handle sluggishly at high speeds but will wobble at low speeds. To have a safe ride that is easy to handle 2-4 inches of trail is ideal.

To figure out the trail of the front end once you know the rake you need more than geometry (like we did in our right triangle exercise). It requires trigonometry.

Now, as you recall I mentioned above, I suck at math. Luckily, not only now thanks to the internet do we have online triangle calculators, but we have rake and trail calculators.

We knew we would want a maximum rake of 45 degree angles. Besides, that would be easier to build than a 42 or 44 degree angle. With a simple right angle triangle ruler we had a measure for where the neck should go.

Step #1 level the trike

Step #2 measure 45 degrees and mark frame

Step #3 cut down neck angle (since we had to replace the neck piece entirely it was cut off)

Step #4 weld new neck on at proper angle

This is not the final finished piece, but it is as far as we got that day. There will be more welding to reinforce the strength of the neck. VW Trikes have a tendency to pop wheelies so we want to make sure the neck is strong enough to handle it.

Just behind the frame you can see a piece of sheet metal up against the wall. We will use metal from that to blend the center piece between the tubes of the frame to make it cleaner and stronger. Eventually most of this will be covered by the gas tanks.

The frame

I was so excited when we got the frame back to The Shop. The first step was going to be sandblasting the frame down to its bare metal. I was told by C that they had a sandblasting machine at The Shop and I just had to get the material for it.

I went to The Pep Boys and bought an enclosed carport canopy and went back to The Shop to try and convince C and his brothers to help me assemble it. Once it was up we went down to Home Depot and bought an industrial power strip some clamp lights to make the carport a useable space, after all winter was coming. Even if it is Los Angeles we still have to deal with darkness and the humid ocean air. I also bought a large roll of heavy duty plastic drop cloth. I went back to the shop and got it all set up. It was clean room quality, or as close enough to it as I was going to get.

The next day I began researching sand blasting materials. Little did I know that high tech cleaning involved either crushed walnut shells or micro rubies. Who would have guessed? However, the more I read online the more it seemed do it yourself sandblasting was pretty problematic. All the sand blasting materials to purchase via the internet were pretty pricing if for no other reason than shipping costs. Eventually, I went back to Home Depot to see what they had. They had no idea. I talked for five different people about sand blasting media and eventually waited around for 20 minutes until their "expert" was free. He directed me to a $5 bag of sand and told me that was what people used, even though the bag said not to use for sandblasting on it. They were no help. I bought the bag and schlepped it back to The Shop.

C and the brothers assessed the situation. R had dug out the sandblast machine for me. C was concerned. I told him about all the research I had done. After conferring with A and R they decided I probably should outsource the sandblasting job just to be safe. I agreed I did not want any of the Brothers put in health jeopardy from flying silicon micro particles from the sand.

Back at the computer researching sandblasting businesses in my area I was trying not to get discouraged. Of course this was going to be more expensive than I expected. Of course The Brothers were going to proceed cautiously. I proceeded forward without complaint since it was my project. I learned about powder coating and while it had an appeal it was too expensive. I tried using the web to find pricing and turn around time information, but despite being the 21st century this was near impossible. Finally I resorted to old fashioned phone calling, but even this was challenging as many businesses had closed or I was dealing with contractors who were out and about.

Finally, I found a place in the neighborhood. They would not quote me a price without seeing the item. I met C at The Shop early one morning before work and we took the frame to the metal working shop. One day turn around and the same price I had been quoted elsewhere. A deal was struck. We left the frame and picked it up the next day.

Now we had a clean frame, a place to store it, and primer and Bondo to repair it.

Phase 1: Research and Design

As I began my process it was clear I was in charge of finance, research, and design. Each month I planned to set aside a few dollars towards my project. I scoured informational pages on building VW trikes. Guys had been doing this for decades and there was a lot of information out there, both through chopper websites and VW aficionado websites. I had a lot of homework to do. I thought C and his brothers might be able to use the spare parts. No, I was told, there was no extra space at The Shop for more vehicles until some other project was finished or a vehicle was sold. There were webpages where guys would build frames for you, but that was thousands of dollars I did not have. Several of them sold instructional manuals on how to build your own, but most of them believed it was a bad plan (because they wanted you to buy one of their's). Solution, buy a frame.

I began with Craigslist and The Samba. One guy in San Diego wouldn't sell me his frame because it was too much for a little girl like me to handle. Geesh! I gave C the contact information and let him work on this old coot. To know avail. Eventually, I found a guy in the desert who was emptying out unfinished projects from his yard. He said it was a '69 VW bug rear end he welded to the front end of a Harley. He said any standard Harley front end would fit it. Deal!

Mid-August I got C to load into my car, because it had working airconditioning, and out we drove to the desert. It was actually hotter in the Valley that day than it was in Lancaster, but either way we were glad to have the AC. The frame was ugly. It definitely needed sandblasting, but no structural damage, just cosmetic patches. $200 and a handshake. Now the project has officially begun.

Introduction

In August 2011 I found myself in need of inspiration. It had been a hard summer and the upcoming year did not show signs of improvement. My health continued to be problematic with little insight from the medical community. My hobbies were falling by the wayside with my increasing disability. I decided I needed a project.

I call it falling down a rabbit hole. You know how it goes... you're reading something interesting online, you click on a link that leads to something else equally interesting, and the next thing you know you have stumbled upon something that catches your eye. You have gotten somewhere, somehow, and you're not sure what link got you there, but you are happy you found it. This happens to me often.

When I was five years old my Dad retired from the U.S. Air Force and we moved to Torrance, CA. The house and neighborhood served us well, and was not bad, but it was not where they hoped to be. At the end of our block, across the street from the middle school soccer field, was a biker bar called The Deep Sands. I always remember before its doors closed and it became an insurance agency all the big choppers sitting out in front. At that age I only really had three goals for myself: to own a leather jacket, to be able to play guitar, and to ride a motorcycle. Yes, I did used to pretend to be Elvis, and play Hound Dog on a tennis rackets as if it were a guitar; I knew all Danny Zukos' parts from Grease. Living near The Deep Sands seemed appropriate to my little impressionable mind.

One day in August I fell down a rabbit hole thinking about The Deep Sands and my unfulfilled childhood life goal of driving a motorcycle. Sure, I'd ridden dirt bikes around, but I could not go for a ride down the street. The increasing neuropathic issues with my hands made it less and less likely I was going to be able to either. Five years ago clutching was hard enough, now I wouldn't be able to use the handbrake either. Somehow in my head I got the notion the three wheeled choppers with high backed seats were called Cheetahs. There certainly is a 70s toy 3-wheeled chopper of that name, and a modern motor trike company, but neither fit the image in my head. So I started cruising the web and diving in rabbit holes to see what I found.

Eventually, I found that in the late 60s and early 70s when Harley Davidson was sold to American Machine and Foundry and the quality of the bikes decreased guys who liked to chop up bikes started welding the front end of a Harley onto the rear end of a VW Bug. Thus, the VW Trike was born. It just so happens that I have a friend, who is an engineer, who is also a gear head, who also likes to work on Harleys and VW Bugs. I asked C if he had ever worked on something like this, and C said no. I asked him if he would be interested in working on it with me, and C agreed.

*** C likes to fly below the radar and has asked not to be named in the blog, unless of course it is for a job referral and you want him to build you a chopper.