SB20 - How to Service the Bottom Bracket Cartridge

Bottom Bracket Cartridge Removal

A few months ago, I showed how to remove and replace an SB20 smart bike bottom bracket cartridge:

SB20 - Replacing the Bottom Bracket

Replacement versus Servicing

Getting replacement parts is more difficult after the Stages shutdown in the US.

Some people in Europe and the UK can still get parts. Not so in other places. For those who can't get parts, servicing your bottom bracket may be your only option. Fear not. Cartridge disassembly is not as difficult as you might think.

July 25, 2024: This vendor has SB20 BBs in stock: Stages Bottom Bracket - Part No. 000-3758. Get 'em while they last 😁.

Bottom Bracket Servicing

This post and video shows how to disassemble and reassemble the SB20 bottom bracket cartridge.

What's Inside the SB20 BB Cartridge?

The SB20 BB cartridge consists of:

1. A pair of retaining cups that secure the bottom bracket cartridge to the frame. Drive and non-drive sides are different.
2. 2 sealed bearing with collars. Both are the same.
3. 103 mm x 22 mm axle with International Splined Interface Standard  (ISIS) splines for connecting to the cranks. 
4. Cartridge shell that helps keep dust and debris from getting inside. 

When assembled, the axle collar keeps the bearings properly spaced and firmly attached (cartridge shell omitted for clarity).

Disassembling the BB Cartridge

The only tools needed are:

• Hammer
• Bench vice
• 3/4" socket extension

Step 1 - Detach drive side bearing from axle

• Adjust the vice to hold the lip on the drive side cup.
• Use a hammer to tap out the axle.

Step 2 - Remove cartridge shell

• Tap the bearing collar until the cartridge shell is released.

Step 3 - Remove drive side bearing from cup

• Continue tapping to push out the bearing. A 3/4 socket extension was used here. Finding an alternative tool should be easy.

Step 4 - Remove non-drive side bearing

• Flip the axle over to put the non-drive side bearing at the top of the vice.
• Use a hammer to tap out the axle.

You can now service or replace the bearings.

Notes:

• Always adjust the vice as close as possible to the axle without actually gripping it. This helps support the inner bearing ring when hammering on the axle or bearing collar.
• Be prepared to hit things fairly hard. The bearings are tight fitting.

Overhaul

If doing an overhaul, remove the dust cover from each bearing and add #2 bearing grease.

Reassembling the BB Cartridge

Do the disassembly steps in reverse.  The easiest way to learn: Just watch the video. 

Watch the VIDEO

The disassembly steps listed above are surprisingly simple.  Re-assembly is even easier.  

See also - How to remove and replace the bottom bracket cartridge:

SB20 - Replacing the Bottom Bracket

=====================

Questions

Can I find the SB20 BB Cartridge from 3rd party suppliers?

The SB20 bottom bracket is appears to be unique to Stages bikes. The axle is 103 mm long. The cartridge is designed to fit a 62 mm frame.

The thread size for the retaining cups is 1 7/8".  Axle thickness is 22 mm.

If you are looking for an exact replacement, the BB cartridge needs to have the following measurements:

Thread Diameter: 1 7/8" (47mm) with left hand threads on drive side.

Fits frame width: 62 mm

Axle length: 103mm

Axle diameter: 22 mm

Axle type: ISIS

DIY Alternatives

The closest equivalent part I have found is the bottom bracket used in these exercise bikes:

• Peloton (all models)
• Schwinn IC and AC bikes - OEM Part# 84990
• Bowflex C6 bike

BB Manufacturer Names:

• Vortex ISD-12
• Vortex ISIS 12

This alternative BB cartridge has the same 1 7/8" (47mm) threads as the SB20. Unfortunately it has a 113mm axle that is designed to fit a 72mm frame. The bad news: This cartridge will not fit the SB20 that needs a 103 mm axle and a cartridge that fits a 62 mm frame. The good news: The bearings fit the SB20 Cartridge! Disassembly and re-assembly steps for this BB are the same as the SB20 steps described above.

Conclusion: The Peloton/Schwinn/Bowflex BB is good for parts 😀.

----------

What is the SB20 BB lifespan?

I did a great of hammering on the bottom bracket shown in the video. I did several practice sessions and there were many outtakes. Neither of bearings developed any play or lateral movement. They continue to spin as good as new.

It's important to note: These are not road bike BBs where dimensions and weight are primary design factors. The outside bearing diameter is 42 mm. The inside is 22 mm. These types of bearings used in electric motors with 10,000 hour continuous life spans and load limits that are much higher than a cyclist can produce. 

Conclusion: Assuming no manufacturing defects and you keep the bearings dry and clean, they should last the life of the bike.    

SB20 bearing specifications:

Bearing type: Deep grove steal roller bearing

Series/designation: 6004/22-2RS 

Bearing size: 22x42x12 mm

Static Radial Load: 1,120 lb (5000 N)

Axial load: 560 lb (2500 N)

For comparison, a BB30 road bearing has about 60% of the load capacity:

Bearing type: Steal roller bearing

Series/designation: 6806 

Bearing size: 30x42x7 mm    

Static Radial Load: 816 lb (3640 N)

Axial load: 408 lb (1820 N)

----------

What type of Loctite adhesive should I use?

If you plan to remove the cartridge for future inspection or maintenance, use blue Loctite. If you expect the re-installation to be permanent, use the original factory applied red Loctite.

I often choose the blue pill. You need heat - plus some cursing and swearing - to loosen a stuck/seized red Loctite part. I like to avoid the cursing and swearing 🙂.

Here's a good summary of Loctite blue versus red.