Conical self-aligning lower roller bearings type 5BT000

The table below shows all key dimensions of the 5BT000 series conical self-aligning bottom roller bearings. We produce 5 main housings and multiple balls with rollers to cover all rudder shafts in full millimetres from 30 mm to 140 mm. The measurement T is the corresponding outside diameter for the rudder tube when mounted over the outer housing. 
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Type 4S000 bearing

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(steps of one full

BODY dia. "D"

(equivalent outside

HEIGHT "H1" / "H2"


LOAD (max)


30 - 45 mm

79 mm

60 mm

120 mm / 65 mm

0,8 kg

1000-1400 kg


46 - 60 mm

99 mm

80 mm

135 mm / 80 mm

1 kg

1900-2500 kg


61 - 82 mm

129 mm

110 mm

135 mm / 80 mm

1,4 kg

3400-4600 kg


83 - 115 mm

159 mm

140 mm

135 mm / 80 mm

2 kg

4700-6500 kg


115 - 140 mm

189 mm

170 mm

150 mm / 95 mm

3 kg

6600-7900 kg

Example: When you want to order a 78 mm conical bearing please use the code number 5BT078.
The 5BT000 series can also be produced with a PETP bearing house. Then add a "P" after the part number.

The applications for the 5BT000 series bearing:
The 5BT000 series bearings are specially designed for production yachts. This bearing type combines a very simple installation with a very smooth operation under all circumstances as the bearing will always be aligned to the rudder shaft. The bearing consists of an aluminium outer housing with an inside sphere turned out. A one piece delrin ball with rollers is located in the sphere. 

This bearing is not intended to be glassed into the hull. The production yard will get an aluminium part with the outer shape off the bearing, the so-called master, and put this on the mould of the hull. After the production of the hull, the conical master will be pulled out leaving a conical negative form. The top will have to be sawed off, and the bearing can be installed. This can be done in a very late stage off the production process, just before the rudder shaft has to be installed. The outside surface of the bearing and the conical hole in the hull will have to be cleaned thoroughly. The outside of the bearing will get a film of sealant (Sikaflex 291 or 221) and pushed into the conical hole. The nut will be mounted and tightened, so the bearing will be strongly fixed inside the hole. The rudder shaft can be mounted with the appropriate sealing system. When the lamination layer is thin and the bearing can flex in the hull it is advisable to make a reinforcement web around the bearing like in below picture. 
This bearing has to be sealed with a neoprene gaiter directly on the top of the bearing, or when the CWL is less than 100 mm below the top of the bearing, an extra tube will have to be fitted. (see the picture below)

The 5BT bearings require a hull master to be fitted in the mould/plug. Please find below the code numbers for the masters. Prices can be found in our pricelist with this direct link.
5BT030M Master for 5BT030 - 5BT045
5BT046M Master for 5BT046 - 5BT060
5BT061M Master for 5BT061 - 5BT082
5BT083M Master for 5BT083 - 5BT115
5BT116M Master for 5BT116 - 5BT140