TPO Parts TRUE RACING Clutch Spring Fabrication
If you have shopped around for clutch springs for your Ducati, you may have seen that there are many companies that sell stainless steel clutch springs. But how do you know which springs are better? Well, here at TPO Parts we take our engineering seriously--and this article will explain why TPO TRUE RACING Clutch Springs are the best you can buy.When we decided to offer our own stainless clutch springs we could have done what our competitors do--just have springs made that are exactly like the OEM springs, but made out of some stainless metal. The problem is that clutch springs aren't a simple cosmetic part. The springs are a vital part of the clutch's performance--and therefore the performance of the whole motorcycle. If you simply change the material that a spring is made from without considering the implications of that change, you can end up weakening the grip on the clutch discs, and decrease clutch performance! Our engineers sat down with a clean sheet of paper to design a clutch spring that not only was rust-free, but also addressed the performance concerns of your standard Ducati clutch.
Because stainless steel alloys have different mechanical properties than standard steel, we had to revise the coil design of the spring in order to deliver the proper clamping pressure to the clutch and to prevent the spring from bottoming or kicking out sideways when the rider activates the clutch (this is known as spring instability). To do this we took careful measurements of the OEM clutch springs and consulted with outside mechanical engineers specializing in spring design. Together, we created a new spring design that incorporates a new spring material as well as a revised winding design that delivers the proper spring pressure and compression performance for use with a Ducati clutch. We double-checked our new spring's design with computer modeling as well as testing on our own motorcycles (also known as our patent-pending Pavement Eating Testing).
Our final design is made out of stainless steel wire--but not any generic stainless. TPO TRUE RACING Clutch Springs are made from MIL-spec certified alloy wire. We mandate that our wire supplier provide material analysis for each batch of wire that we purchase. You can see one such certificate here.
Try asking one of our competitors what kind of wire they use, and if they can document it.
The geometry of the spring is designed to exceed Ducati specs for clamping pressure and closed height. This means that TPO springs minimize slip and provide a clean release of the clutch every time. Our springs are manufactured to exacting standards and are certified under ISO quality control procedures. We keep our paperwork on file to prove it. You can see one of our certificates of compliance for our springs here.
When we receive our springs from the winder we perform a two-step polishing process to put a mirror shine on the springs. We use a synthetic ceramic media for primary finishing, and then follow up with an organic media to perfect the finish.
We then perform our own in-house quality assurance inspection and grading process above and beyond the ISO procedures that have already have implemented. We test each and every spring for free height and spring rate. It is more costly to polish first and then grade the springs, but this is the only way to ensure that the spring's properties are not altered by the polishing process.
Here you can see our spring testing station. The newly polished springs are in the blue bin to the left. We use special instrumentation to measure the spring's free length and the spring rate. Springs that are out of spec are discarded, and TPO's in-house standard is four times more stringent than OEM. Those springs that pass our inspection are sorted by rate into the yellow bins to the right hand side. When you purchase a set of TPO TRUE RACING springs you receive a set of springs that are matched with equal rates to make sure your clutch pack is evenly loaded.
Our test rig loads each spring to each of several compressed heights. We check the load at each point to ensure the spring behaves as it should. This instrument simultaneously measures the amount the spring is being compressed as well as the force the spring is applying. This exact spring you see here is actually out of spec, and was discarded.
After load-testing we go on to check the free height of every spring. Again, any spring that is too long or too short--even by a tiny fraction of an inch--is discarded.
This elaborate procedure ensures that TPO TRUE RACING Clutch Springs are the best you can buy for your Ducati. Not only are the springs bright, shiny, and rust-proof, but they also deliver superior clutch performance. No other manufacturer goes to this effort to provide quality clutch springs. We call our springs "TRUE RACING" springs because they are the ONLY springs that are truly designed and manufactured for performance purposes.
