One of the questions I hear racers say to one another is “how much toe in are you running?”. On average, rear toe in can range from 2 to 3.5 degrees. Toe in is adjusted in a numerous amount of ways on the various touring cars. Pictured above you can see the Tamiya TRF416. The blocks are notated by letters…others are numbers….and so on.
Toe in effects the stability of your car emmensely. At the same time, it takes away from straight line speed. A good rule of thump is to use the minimum amount of toe in necessary to have a stable car.
Many times, racers will feel a lose feeling in their car during a run. One of the first things they think of doing is adding toe in. This can work in some cases, but not in others. Sometimes, loose handling is a result of quick weight transfer….or namely too much weight transfer… too quickly. In that case, adjusting the toe in is just a band-aid to fix a more permanent problem that could be related to droop, oil, shock springs, and so on.
When a touring car enters a turn, it rolls much of the weight to the opposite direction you are turning to the front outside tire.. This momentum forces chassis level roll. It is at that time you tend to let off the trigger turn. When you straighten your wheels to exit the same turn, you tend to accelerate to the next turn. This is at the point your car’s chassis is near flat. A good rule of thumb regarding to in is…..Do you have enough forward traction coming out of a turn? If not, you may need to consider going to more toe in. Conversely, you don’t want too much forward traction as well. As this will rob you of straight line speed and perhaps overall corner speed. You want just enough and no more that that.
Next up roll center ……..
Most of the cars have roll center adjustments. For the purpose of this tip, I am specifically talking about the rear end roll center adjustment.
This can be adjusted with spacers inserts, washers,etc. (see pictured above). This is adjusted different on various cars. Typically, whatever you do to the front part of a rear arm, you do to the back. So if you are running .5mm spacers on the rear arm’s front block…do it to the rear arm’s rear block as well. Most of the time, arms are ran flat in respects to the chassis.
Using spacers places the weight of the suspension components higher in respect to the chassis. If you are using a base droop setting based on a setup, you will need to re-set this. It will change your dampening pre-load. Also, it will cause your upper suspension tie-rod to change angles. You may or may not want to change this based on how your car is handling.All of these need to be taken under consideration before running.
So what is the end effect? Well, it will basically loosen up your rear end. Have you ever had problems with your car pushing badly? Too much traction coming into a turn? Too much side bite coming out a turn? Is you car slow in transitioning from corner to corner? Have you ever driven you car and heard the tires squeal? This is a result of the tires becoming too hot and overworked. This can be caused by too much weight being shifted to the tires. Increasing the roll center just .5mm to 1mm can alleviate alot of the problems mentioned. This tends to save your tires from shredding as well. Try it sometime…it works for Vader…it will work for you!
