AFCO torque links are designed for reliability, minimal maintenance and maximum performance. Some Afco torque links utilize polyurethane spring bushings to absorb engine and/or brake torque. Afco torque links equipped with poly bushings have proven to provide excellent traction in all track conditions. Afco poly spring bushings are made with the highest quality polyurethane materials and are designed to provide both exceptional performance and durability. The following information answers some of the most common tech questions regarding torque links equipped with poly spring bushings.

WHICH BUSHINGS SHOULD I USE?
Which bushings should I use? A combination of factors determines what poly spring bushing is best for a particular application. The main factors include the technique of the driver, the torque curve of the engine, suspension type, track conditions, tires and the mounting position of the torque link. Typically, soft bushings are best when the driver, engine, chassis, tire and track condition combination prevents the quick application of engine power or when off throttle handling is loose. Hard bushings are best when a considerable amount of engine power can beapplied quickly at corner exit or when off throttle handling is too tight. The chart below provides a starting point for bushing selection. The listed Engine bushings affect on throttle handling whereas the Brake bushings affect off throttle handling. NOTE: Extremely soft engine bushings can cause a lot of axle wrap-up during acceleration that can lead to driveline problems.

BRAKE BUSHINGS (2.250" OD)
Red poly spring bushing, # 21209-3R (Red/Hard), is recommended for most applications. You can tighten off throttle handling by adding a second 21209-3R bushing if space permits or by switching to a single #21209-3B (Blue/Med.) bushing. Keep in mind that the use of brake bushings softer than those listed may cause excessive axle wrap-down during deceleration that can lead to driveline problems.

HOW MUCH TRAVEL?
You need to have enough torque link travel to hook up the racecar off the corner. Some racers are hooked up when the torque link travels 1.25” during acceleration while others need 2.5”. Torque link extension travel of approximately 1.5” generally provides good forward bite, stability when the torque link unloads during deceleration, plus good bushing and driveline life. Generally you’ll soften the engine side bushing combination to increase extension travel and improve forward bite in slow slick conditions. However, excessive torque link extension travel can overly delay the application of power to the tires and make the racecar feel as though it lacks forward bite.

HOW LONG DO BUSHINGS LAST?
Bushing life is mostly affected by the amount and frequency a bushing is compressed. Bushings compressed no more than approximately 30% of their static height may last a whole racing season. Bushings compressed beyond this amount on a regular basis will need more frequent replacement. Afco torque links typically include travel indicators that show the amount of bushing travel. Over time the chemical makeup of poly spring bushings can change, especially in hot humid conditions. At the least you should replace bushings during the off-season.

WHEN SHOULD BUSHINGS BE REPLACED?
There are a number of factors that indicate the need to replace bushings:

1. Bushings have lost free height. When a torque link loses its preload it’s usually due to the poly bushing/s losing their free height. Replace bushings if torque link preload must be readjusted more than twice.
2. Center hole of poly bushing becomes oblong.
3. Heavy wear marks appear on the outside of the bushings due to interference with the 3 stand-off tubes. Note that the appearance of minor wear marks is normal.
4. Forward bite diminishes for no apparent reason. Check preload first and readjust if necessary (See item #1 above).

WHAT CAUSES A BUSHING TO BREAK?
In most cases bushing breakage, while rare, is due to over-compression of the bushing. This is particularly the case when bushing breakage has occurred more than once for a particular application. The use of stiffer bushings is recommended in such cases. NOTE: Replace any bent poly spring retainer/seat to help avoid bushing breakage.

HOW MUCH SHOULD BUSHINGS BE PRELOADED?
Keep in mind that poly bushings become progressively stiffer when compressed. Therefore, any change to bushing preload affects the torque link’s spring rate and, consequently, traction. You can experiment with preload, especially to affect forward bite. Start out with 1⁄4” preload and adjust in 1/8” to 1/4” increments. The torque link becomes stiffer when preload is increased which quickens the application of power to the tires and vice versa. Note that it’s generally better for overall handling to soften bushings rather than reduce preload below zero.