TOE IN … A VERY IMPORTANT MATTER
The steering geometry of tadpole trikes is complex and it is important that everything is right in order for proper and safe operation. Toe in is a common steering setting found on cars, trucks, buses, etc. Here is a drawing of this adjustment using a car for illustration:
On a tadpole trike this adjustment should never be set to where there is toe out. Most manufacturers recommend about 1/16 of an inch toe in. However, the truth of the matter is the closer you can get it to neutral and still handle well the better. By neutral I mean the wheels are straight … no toe in and no toe out. If this adjustment is off very much it can seriously effect the handling as well as wear the tires out very quickly as the rubber will be “scrubbed” off.
Making this toe in adjustment is relatively easy, especially on a direct steering trike. On an indirect steering trike it is a little bit more involved, difficult and time consuming. A tape measure can be used although I personally think there is a better way which is easier and more accurate. They make a tool to do this. Catrike sells one called the Calibro. It sells for about $50. It is rather large and so in my opinion is a bit difficult to use. Keep in mind that oftentimes there are such things as cables, wires, spokes, fender braces, etc. to contend with. Trying to use a large tool in these areas can be challenging. Again, personally I think there is a better way (better tool and much much cheaper … maybe even free). I use a telescoping radio or tv antenna. I already had two or three of these laying around so the price was right. 🙂
It is the “cat’s meow” as far as I am concerned. For those who don’t understand this American expression, “cat’s meow” simply means perfect or ideal. Just make sure the antenna telescopes out far enough to reach the distances involved. I don’t advise using the tires to measure off of as you may not get as accurate measurement on them as you will on the wheels. Of course, if you wheels are out of alignment or bent you won’t get an accurate measurement.
The way to measure the toe in on a tadpole trike is to take measurements between the front and back of the front wheels. The measurement should be taken as close to the center of the wheel as possible front and back. You many have to go on the bottom of the boom on the front and on top of the boom in the back to keep the measuring position the same height off of the ground front and back. The measurement in the front should be approximately 1/16 of an inch less than the measurement in the back. When the rider is seated on the trike this measurement will change somewhat … depending upon the weight of the rider and the frame of the trike (what it is made out of). This is covered in the first video below. The wheels will tend to toe out a little with the riders weight on the trike. Ideally this measurement and adjustment should be made with the rider seated on the trike distributing his weight as nearly normally as he can. To do this it will require another person actually taking the measurement and doing the adjusting to get the toe in set properly. On my trike when I sit down my toe in measurement changes about 1/16 of an inch. So if I am doing this by myself I know I can set the toe in at 1/16 of an inch and then when I sit down in the trike the toe in will change to 0 or neutral … exactly where I want it. Here are a few videos showing how to set the toe in on a tadpole trike … both direct steering and indirect steering.
This first video shows TerraTrike trikes:
This next video clearly shows using the telescoping antenna to set the toe in adjustment on a Catrike:
The third video shows adjusting the toe in on an ICE trike:
Lastly, this next video shows the Calibro tool being used on a KMX trike:
Did you notice that these guys are riding on the wrong side of the trail? 🙂
I have found that this toe in setting can change by itself even when the lock (jam) nuts are tight. So I highly recommend checking the toe in measurement periodically to make sure it hasn’t changed. Rembember handling and tire wear will be effected should the toe in adjustment get off too far.