most of us were falling asleep in Geometry class, we
didn't realize that we were learning important RC
principles. Geometry is everywhere in RC: symmetry,
shape configuration, and not to mention, angles out the
wazoo! When dialing in your car's suspension, toe angle
(the horizontal tilt of the wheels) must not be
overlooked. If toe angles are set correctly, you can get
the most out of your suspension, meaning it will keep
you moving straight and cornering aggressively.
Inconsistent toe settings, however, will send your
vehicle into unpredictable directions and greatly affect
handling in general. If you did fall asleep in 2nd
period, no worries! I'm Mr. Wortel, and I'll be your
substitute for the next 15 minutes.
Words: Michael Wortel
Part 1: WHAT IS TOE ANGLE?
Looking down onto your vehicle, you may notice that the front and rear
wheels can be adjusted horizontally, causing them to point in or away
from the chassis; this is the toe angle. Angling the toe so the front
of the wheels are pointing toward the center of the chassis is toe-in.
The opposite of toe-in is called, intuitively, toe-out. This occurs
when the rear portion of the wheel angles toward the chassis. The most
important part of toe adjustments is consistency. If toe on one side
is different from the other, the vehicle will certainly veer off and
hit a wall, or the car belonging to the guy driving next to you (not a
good way to make friends at the track).
Part 2: HOW TO CHANGE IT
Changing toe angle is much like adjusting camber links. To change toe
on the front wheels, lengthen or shorten the turnbuckles with a wrench.
Lengthening them will result in toe-in, and shortening provides
toe-out. Changing toe in the rear can be more complicated. Some
vehicles use turnbuckles in the rear, but most are fixed and require
changing wheel hubs or bulkheads. Initially, set the front toe to 0
degrees. If the rear toe is adjustable, set it to -1 degree, although
this can differ for on-road and off-road applications. It is important
that the toe settings are symmetrical from side-to-side, so use an
adjustment grid or stand to ensure accuracy. If these tools are not
available, you can easily make one yourself, drawing vertical lines
and measuring toe relative to 90 degrees. This seems old school, but
it works well.
Making A Toe Adjustment Grid
Now it's time to put your geometry skills to use. It is easy to make a toe adjustment grid without having to purchase a stand.
1.) Use a piece of paper that is bigger than the footprint of your vehicle.
2.) With a ruler, draw a vertical line on one side of the outer wheels, making sure that it is at a 90 degree angle with the front edge of the paper.
3.) Then, draw an identical line on the other side of the vehicle, also 90 degrees from the edge of the paper.
4.) What you have now are two straight lines to compare your toe angles with. Use a prOtractor to measure the toe relative to the line on each side. If the angle is a perfect 90 degrees, then that side has neither toe-in nor toe-out. This will ensure that your angles are accurate and symmetrical.
Part 3: WHEN DO I ADJUST TOE
It is impossible to make one generalization for toe setups, because they vary for on-road and off-road, as well as from track to track. Toe settings, however, are universal in how they affect handling. In general, toe-in on the front will result in stability on the straights but with increased drag. Toe-out will result in increased cornering but will feel more volatile on the straights. In the rear, toe-in counteracts oversteer and increases forward traction, as well as increasing off-power steering. Increased rear toe-in, however, will reduce straightaway speed. The only time you would ever use toe-out in the rear would be for rock crawling, because it would allow the rear end to swing around turns.