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Setting Toe on Front Wheels of a Trike (Catrike)

Mikey says: Toe is a measurement of the horizontal diameters of the two front wheels, and how close to parallel they are to each other when the wheels are pointed straight ahead. If they’re not parallel, the wheels either “toe in” (the fronts of the wheels are closer together than the backs of the wheels) or “toe out” (backs are closer). I’ve seen people use a tape measure, piece of string, Catrike flagpole, trammel points, framing squares, or (last resort) a special tool. Once you’ve got a way to measure the inter-wheel distance front and rear, just fiddle with a tie-rod end to tweak the wheels to make the distances equal, or at least within about 1/16″ of each other. Loosen the stop nut, disconnect the tie-rod end from the bracket on the wheel, turn the rod-end in (adjusts the toe “out”) or out (adjusts the toe “in”). The finest adjustment you can make is a half-turn of the rod end, so you may have to settle for a tiny bit of toe. Some people prefer toe-in, others toe-out if they can’t make it exactly neutral, and some people don’t want it exactly neutral anyway. Once you’re happy, reconnect the rod-end to the bracket, tighten the stop nut, and go riding.
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trikebldr adds this about toe:

Basically, toe-in gives better stability at higher speeds, but higher tire wear. Toe-out will give more nimble, power-steering feel, with more tire wear. Neutral toe will give a balance of the two, with very little tire wear.

To explain the stability issue, think of it this way; with toe-out, each wheel is trying to pull the trike in it’s direction, and when you try to go straight and hit even a tiny bump with one wheel, that wheel gets a traction advantage over the other and begins to turn the trike it’s direction. As it does so, the weight advantage transfers to the other wheel. And, this cyclic action happens over and over, making the trike feel very unstable. Example: left wheel hits a bump, gets more traction than the right wheel and the trike starts to turn to the left, shifting the weight over to the right wheel. Now, the right wheel has more traction than the left, so the trike starts to turn to the right, shifting the weight over to the left wheel. This cyclic action happens over and over, creating an unstable, unpredictable feel for the rider. It manifests itself as a tendency to wander from side-to-side.

With toe-in, when one wheel gets a weight advantage and tries to turn the trike, that action only adds more weight to that wheel and nothing changes, giving a feeling of stability. No wandering!

Absolute neutral toe tends to feel more like toe-out at very high speeds, so just a touch of toe-in is preferable for most riding conditions, but not so much that it causes tire wear. That’s where it gets tricky! I run all of my trikes at zero toe when unloaded (in the work stand), and that gives it just a hair of toe-in when I sit on the trike. My original set of Stelvios on my ’07 have over 9000 miles (YES! NINE THOUSAND!), and are still useable. I replaced them only because Tickle Pink was going to be riding that trike during the rally week this year, and I wanted it to be absolutely trouble free. I think this setting has well proven to be optimal for at least my ’07 Speed. Tire wear on my ’08 looks good so far, too, with this setting, and it has over 2000 miles so far.

Here’s a little bit about setting toe. The trueness of the wheels can kill an adjustment completely!!! If each wheel wobbles even 1/32″, and they are in just the right position to each other during the toe setting, that could affect the setting by 1/16″, and that is all I would recommend as a maximum toe-in value. So, even if you actually have neutral toe, it COULD look like 1/16″. The only way to eliminate that is to bind the wheels slightly by adjusting the brake pad just enough to hold the wheel from spinning freely, but allow you to rotate them during this operation. Now. working from the right side, take your toe reading, front and back. Write it down. Now rotate only the right wheel 1/4 turn and take the toe reading again. After doing this at the four “corners” of the right wheel, rotate the left wheel 1/4 turn and start over on the right wheel. This means you will be taking sixteen readings total to see how much your wheel trueness affects the real toe setting. An average of all sixteen values will be a very accurate reading!

This is all very tedious, but if you like a very accurately tuned machine, it is worth it. And, once done to this accuracy, it shouldn’t change unless you take things apart or bend something. My ’07 never changed, and it was never apart in over two years until I recently took it completely apart for “surgery”. My ’08 is now almost 18 months old and has also never changed.

2 comments to Setting Toe on Front Wheels of a Trike (Catrike)

  • Mike Armstrong

    The Catrike forum has a recently-developed forum on Toe-in/out with some real engineering data and analysis that’s worth a read, and definitively shows that a small amount of toe-IN is what you want.

    http://catrike.yuku.com/topic/3848

  • Olmon

    To correct for lateral run-out on your wheels, raise the trike so the wheels can be spun & with a colored marker, mark the centerline of each tire by spinning it against the marker. That will give you the true center to measure toe-in or out from.

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