Slewing Bearings RU178G

115 × 240 × 28 mm | GCr15 Steel | P5

When buying RU178G, the model number is only the starting point.

For a replacement order, what matters more is whether the new bearing matches the old one in size, mounting method and running condition.

RU178G has a 115 mm bore, 240 mm outside diameter and 28 mm width. It uses bearing steel and an open design. The standard precision grade is P5, with other precision grades available depending on the order.

If you already have a drawing or an old bearing, it is better to compare the actual dimensions before placing an order.

You don't need a complicated inspection for the first check.

Start with the basics:

For a production order, dimensional inspection should follow your own drawing or incoming inspection standard.

A model number can sometimes be copied incorrectly when an old bearing is replaced.

Before confirming the order, check:

① Bore - 115 mm

Make sure the shaft side matches.

② Outside diameter - 240 mm

This needs to fit the mounting seat.

③ Width - 28 mm

This is easy to overlook when installation space is tight.

④ Precision

P5, P4 and P2 should not be mixed up. A higher precision grade also means the surrounding parts may need better machining.

⑤ Bearing condition

Check whether you need an open bearing or another configuration.

These five points are usually more useful than simply asking for "the same RU178G."

Preload is easy to overlook when ordering a crossed roller bearing.

A bearing with too little preload may have unwanted movement.

Too much preload can increase friction and heat.

So we do not recommend choosing preload simply because another machine uses the same bearing model. The required value should be checked against the actual load, speed and accuracy requirement.

If you are replacing an existing RU178G, providing the original preload information can help us confirm the replacement more accurately.

If this is a replacement purchase, we recommend keeping the old bearing nearby when checking the quotation.

Take a few measurements and compare them with the drawing.

If the original bearing has markings, send us a photo of them. If there is no clear model marking, send:

Bearing photo

Inner diameter

Outer diameter

Width

Mounting drawing, if available

This can help avoid ordering a bearing that looks similar but does not fit the machine.

1. Why use an RU bearing instead of two ordinary bearings?

This is one of the main reasons to look at the RU series.

A crossed roller bearing can deal with radial, axial and moment loads in one unit. In some designs, this means you don't need to arrange several standard bearings to get the same type of support.

Whether it is actually better depends on the machine design.

2. Does a larger bearing always give better stability?

Not necessarily.

For rotary equipment, the bearing's roller arrangement, internal clearance or preload, mounting accuracy and stiffness all have an effect.

Simply moving to a larger bearing is not always the right answer.

3. What should I check if RU178G is replacing an existing bearing?

Don't check only the 115 × 240 × 28 mm dimensions.

Also compare:

Mounting method

Shaft and housing fit

Required preload

Rotation accuracy

Load direction

Lubrication method

Two bearings can have the same outside dimensions but still not work in exactly the same way.

4. Can I install RU178G in a standard bearing housing?

Not usually in the same way as a standard deep groove ball bearing.

The RU design uses its integrated rings and relies on the surrounding machine structure for mounting.

For replacement work, the housing drawing is therefore important.

5. What if my equipment requires very low runout?

Then P5 may not be the only specification you need to look at.

The mounting surface, shaft, housing and preload can all affect runout. If your equipment has a strict runout requirement, provide that value when asking for the bearing.

Hot Tags: slewing bearings ru178g, China slewing bearings ru178g manufacturers, factory, twose roller bearings, ceramic hybrid bearings, bearing 12mm, metric needle bearings, needle bearing thrust washer, linear thrust bearing