What's "Tri-Bearing"? – RHB Turbochargers


What's "Tri-Bearing"?

Full Metal Free Floating Triple Ball Bearing & What it Means

RHB sought out to improve the reliability, performance, and max RPM possible on ball bearing center sections, and achieved exactly that.

Our tri-bearing center section design is 100% clean sheet, and shares no parts with other brands. This bearing design is tailored around the specific wheel sizes we use that require high RPM to achieve optimal mass air flow.

Tri-Bearing

In typical dual ball bearing turbochargers, the compressor and the turbine side bearings are created equally. However, the forces they experience are far from equal.

The turbine side angular contact ball bearing will have to handle the radial load of the turbine wheel, extreme vibration from exhaust pulses, extreme heat as well as the bulk of the thrust load in the axial plane. When compared to the turbine side bearing, the compressor side bearing will only deal with a fraction of the heat, vibration, radial & axial load. That being said, it is no surprise that whenever a dual ball bearing turbo fails, it is the turbine side bearing that has either a melted cage, or excessive wear on the bearing races.

This is why we use 3 ball bearings. 2 bearings arranged on the turbine side and 1 bearing on the compressor side. We chose 2 turbine side bearings over a just a larger turbine side bearing because increasing the diameter of one bearing would reduce the max RPM capability of these CHRAs.

Full metal

Full metal means that we use bearings that are completely made up of metallic components. Our bearings are comprised of bearing steel balls, races, and brass bearing cages. In typical dual ball bearing turbos it is common for bearing cages to be made from bakelite (automotive plastic) or a similar composite material. Those materials are known to melt or fail under extreme loads or intermittent lubrication. Brass proves to be the superior material, offering better strength while having little effect on friction.  

Using full metal ball bearings allows our turbochargers to withstand extreme over-spin conditions, high temperatures, and situations where lubrication is intermittent.  

Free Floating Bearings

In other ball bearing turbochargers, the outer races of the bearings are fixed and cannot rotate in their housings. In our turbochargers however, the outer races of the bearings are allowed to free rotate with lubrication between the outer race and the bearing housing.

The benefits of this are relatively straight forward. Aside from creating a cooling film of oil between the outer bearing race and the bearing housing, this free floating configuration for the bearings creates a substantial reduction in friction at high shaft RPM. That's not all. Outer race wear in typical fixed bearing designs will only occur in one spot of the race, since radial load is not equal in every direction. This type of "spot" wear is not possible in our turbochargers since the outer race is always in motion. This configuration will greatly increase the lifespan of bearings that see high loads regularly.

 

 All of these features are offered as standard in all of our universal Tri-Bearing turbochargers, direct replacement CHRA's, and custom bolt on turbochargers. Thanks to modern manufacturing methods, we are able to bring some of the best turbocharging components to the market at very competitive prices!