TWM Tech-Talk July 1st Article
***A quick note. It is possible that not all products discussed in this article are available for your application***
TWM Performance…Cable bushings, Base bushings, and Polyurethane Stay bushings explained!
Truth be told, there is a lot more that goes into making the perfect shift assembly than the average consumer may believe. Most people suppose that once you throw in a short shifter and a nice heavy shift knob, you’ve exhausted all of the possibilities to improve upon your shift feel. This is simply not true, and it is even more so when dealing with your typical, modern cable actuated shifter. Cable actuated shifters often feel more spongy or vague than their rod shifter counterpart simply because of their complexity. In a cable actuated shifter, there are multiple points between the shift knob and the shift actuator on the transmission where large rubber bushings are used and often offer generous amounts of flex. This flex is transmitted directly to the shifter as a sloppy vague feel.
So now the question persists, what can I do to improve upon this vague feeling past your typical short shifter and shift knob modification? The answer comes in the form of superior bushings; both on the base of the in-car shifter assembly, and directly where the linkage meets with the transmission. We’re often asked what the differences are between TWM Performance Base Bushings and Cable Bushings so we’ll try to take an in-depth look at their different purposes and designs in this article.
-Base Bushings (The best bang, for your buck!)
It should be noted that for every cable actuated shifter, we offer base bushings! Essentially, our base bushings are precise CNC machined aluminum bushings that replace the soft and flexible OEM bushings that attach the shifter assembly to the floor of the vehicle. The result is a completely different shift feel. Due to the fact that aluminum won't flex like rubber, your shifter will feel much more solid and precise.
The most noticeable difference after installing TWM Performance base bushings is the definition of the "H" pattern. What I am referring to here is the gates in the shifter. With this added feel and gate definition, locating and selecting gears is easier than ever before.
-Cable Bushings and Transmission Arm Bushings (Metal alloys at work!)
Once one side of the shift assembly has been taken care of with the base bushings inside of the car, it’s time to move onto the other side to where the cables connect to the transmission in the engine bay. Many cable actuated shifters have bushings that connect the cables to the transmission shift lever. This is our final point of interest with our shifter overhaul.
By nature, many of these soft rubber cable bushings are in a housing that must pivot and rotate with the cable. Therefore we had to find a material that would allow for this rotation without causing friction resistance and possible binding, while being hard enough to remove the flex and play that is inherent with the OEM rubber bushings. What we came up with was our Bronzoil metal alloy.
Bronzoil is extremely hard which eliminates all play, slack, and flex in the cable linkage, while having “lubricating” properties to prevent all of the potential negative effects that were mentioned above. While it is not mandatory to use the Base Bushings in conjunction with the Cable bushings, the combination is a recipe for a solid feeling shifter, and more precise, gated shifts each and every time.
Another point of interest is the manufacturing process of our cable bushings. A large portion of the competition uses aluminum or bronze which is prone to binding and cause stiffness and notchyness in the shifter feel due to the non lubricating properties of Aluminum and Bronze. Furthermore, the other brands tend to use crude casting techniques to make their bushings and bearings which makes for large tolerances and a less than smooth finish; two very important things when fabricating bushings and bearings that are tight fit.
Here at TWM Performance we decided to go above and beyond the call of duty. While our metal is already superior to other brands, we decided to use a CNC to make our parts. All TWM Performance bushings are CNC machined to the strictest tolerances to assure a better than stock fit and a perfectly smooth bushing to avoid all binding and metal degradation!
-Polyurethane Shifter bushings (Simple, yet effective)
Let me start off by explaining exactly were these bushings go. Basically the Polyurethane bushings are used on cars with rod actuated shifters. There are two rods on a rod actuated shifter setup; one to select the gears in the transmission, and another that is a "stay" rod which keeps the shifter solid in its pivot base. The polyurethane bushings that we make here at TWM Performance go where the stay rod connects with the transmission casing. From the OEM, there is a weak, soft and mushy rubber bushing that creates this connection. This creates a vague feeling in the shifter, and only gets worse as the rubber bushings age.
TWM Polyurethane bushings not only fit better than OEM bushings, but they are stiffer and more durable than the OEM rubber as well. You can rest assure that a TWM Performance Polyurethane bushing will last you the life of the vehicle and that it'll provide you with a firm and connected feel to you to your transmission that you thought would never be possible!
Now, all of these claims are great, but you may still be asking yourself, what can be so special about polyurethane bushings, and why are TWM's bushings so much better than the next guys...
Well to be honest it’s pretty simple; it’s all in the quality of the polyurethane used, and the molding process. Here at TWM Performance, we use the highest quality polyurethane along with high-tech ovens and vacuum chambers to insure that there are no bubbles or cracks in the bushings. Lower quality polyurethane tends to have bubbles in it which will lead to a soft bushing that will wear faster.
Secondly, it’s all in the fitting of the piece. You want the bushings to be tight enough to provide the most solid and connected feel allowable, but they need to fit and be easy to install. Our engineers work and test our bushings until they find the most perfect fit possible for each and every application. Add to that the most stringent quality control procedures on the market, and you’re guaranteed to be satisfied each and every time you buy a TWM Performance product.
When it comes down to it, the most important aspect of purchasing products for your car is knowing what you’re buying and knowing the features the product offers, even though you may not be able to see them. Hopefully this article will have shed a little light on some of our products!
Thanks for reading and as always, all comments, questions, and opinions are welcome!
Team TWM Performance