From the Workbench: At-Home Bottom Bracket Maintenance 5

It's no secret, press fit bottom brackets are far from perfect and require attention fairly often. Sometimes it's a quick snugging up of the cranks, and sometimes they require a full tear-down, clean, and lube to rid your bike of the dreaded creaky climbing syndrome. Thankfully, this job is pretty straightforward and can be done in as quickly as ten minutes by a seasoned mechanic. But what if you're not a seasoned wrench? We have you covered, and will walk you through the process step by step. And, even if you don't have a press fit bottom bracket, this tutorial is still for you as we touch on external and threaded bottom brackets, which too, are often are the culprits of creak. 

Tools Needed

• Hex Keys (AKA: Allen Wrenches)
• Bearing Press or Dead Blow Hammer
• Appropriate Bottom Bracket Tool
• Appropriate Crank Bolt Removal Tool (ie. Shimano / Truvativ Crank Bolt Tool)
• Crank Arm Puller (For Cranks not spec’d with self-extracting crank bolt)
• Grease
• Denatured Alcohol
• Rag or Paper Towels

Step One - Removing the Chainguide

Skip this step if your bike isn’t equipped with a chainguide. If you have a guide, determine what size allen wrench is required to remove or loosen the guide’s sliders/rollers. Our guide required a 4mm allen wrench to loosen the top slider. Note that most current chainguides don’t require you to completely remove the sliders/rollers in order to remove the chain and get out of the chainring’s way to remove the crank. Adjust or remove your sliders/rollers accordingly and remove the chain from the chainring (it can just hang on your bike). 

Step Two - Removing the Cranks

Determine if your cranks require a specific crank bolt removal tool (Shimano and some Truvativ). If so, use the crank bolt removal tool to unscrew the crank bolt. Note: Shimano users, be sure to loosen the two pinch bolts with a 5mm allen wrench. Our cranks came equipped with a self-extracting bolt, which requires an 8mm allen wrench to remove the non-drive-side crank arm. 

Lower-end and older cranks will sometimes require a crank arm puller. If this is the case with your cranks, remove the crank bolts with either an 8mm or 10mm allen wrench, thread the crank arm puller completely into the crank arm, and turn the handle clockwise until the crank arm comes off. Repeat this for the drive-side crank arm.

For those with spindle equipped cranks, with the non-drive crank arm removed, pull the drive-side crank out. If you’re getting some resistance, you can use a dead blow hammer or your hand to tap the spindle from the non-drive-side to get it moving. 

Step Three - Removing the Bottom Bracket

Ah, standard. There are quite a few different bottom bracket standards if you didn’t already know, so this step, depending on your specific bottom bracket, can be done a number of different ways. We’ll cover press fit in the photos, as well as give a few general guidelines for threaded bottom brackets. 

General Guidelines For Threaded Bottom Brackets

Use the Right Tool: Shimano/Truvativ, e*thirteen, etc. all have specific tools to remove the bottom bracket, be sure to use the correct one.

Righty Isn’t Always Tighty: For threaded bottom brackets, the drive-side bottom bracket cup is reverse threaded, meaning to remove it, you’ll have to turn it clockwise. The non-drive-side cup is threaded in the standard righty-tighty/lefty-loosey direction.

Remove Non-Drive Cup First: This may just be an old habit from cartridge style bottom brackets, as it not required on all bottom brackets anymore, but it’s good practice to always remove the non-drive-side cup first due to some bottom brackets still requiring removal in this order.

Grease it Up: Always remove old grease from the bottom bracket and the bottom bracket shell. Re-grease the threads on both the bottom bracket shell and bottom bracket cups.

Install Drive-Side Cup First: Just like removing them, you’ll want to do this in order by installing the drive-side of the bottom bracket first (remember, it's reverse threaded). Once fully tightened, then install the non-drive cup.

Now, if your bike is press fit like ours, you’ll have to knock the cups/bearings out. Our bike doesn’t require bottom bracket cups, with the bearings just pressing into the frame, but the procedure is the same for both cupped and non-cupped bottom brackets. 

If you don’t have a press-fit-specific removal tool, as we don’t, a headset cup removal tool will do the trick. Slide the tool through the bottom bracket until the flanges squeeze through the bearing/cup and snap into place behind it. Making sure it’s fully seated, use the dead blow hammer and the cup removal tool to knock the cup/bearing out of the frame. Repeat this process to the other bearing/cup. 

Step Four - Clean, Inspect, and Re-grease

Now that the bottom bracket it out, thoroughly clean both the bottom bracket shell and the bottom bracket itself with a rag or paper towel and denatured alcohol. 

With the old grease removed, visually inspect the bottom bracket cup to check for any cracks or damage that could cause creaking. Also, spin the bearings in your hands to feel for any roughness. If the bearings are notchy, they should be replaced with new bearings.

If everything checks out, apply new grease to both the bearing/cups and the bottom bracket shell. 

Step Five - Install the Bottom Bracket (Press Fit)

With everything freshly lubed, slightly press the bearings or cups into the bottom bracket shell by hand. Put the tool through the bottom bracket shell, slide and lock the lower bushing onto the press. Slowly press the bottom bracket in with the bearing press tool. Make sure they’re going in smoothly, straight, and without excessive resistance. You can damage the frame during this step so use caution and care during this process. Once the bearings or cups are fully pressed in and flush with the bottom bracket shell, remove the tool. 

If you don't have a bearing press on-hand, you can install the bearings or cups by using a dead blow hammer. But, we stress using EXTRA care when installing press fit bottom brackets this way. Install one cup/bearing at a time by slightly pressing them in by hand, and gently tapping them in with the dead blow. Make SURE they are going in as straight as possible and are fully seated while flush with the bottom bracket shell when finished.

Step Six - Install the Cranks

If you haven’t already wiped the old grease off your cranks and spindle, now is the time to do so. Apply new grease to both the areas on the spindle where it contacts the bearings, as well as in the inner race of the bearings themselves. 

Slide the spindle through the bottom bracket. It may need a little coaxing with your hand to get it completely through. Apply more clean grease to the spindle/crank interface and slide the non-drive crank arm over the spindle, making sure the crank arms are clocked properly. Tighten down the crank bolt with the appropriate tool, which is an 8mm allen wrench in our case. 

You can now put the chain back on the chainring. If running a narrow/wide setup, be sure to line the wide links of the chain up with the wide teeth of the chainring. 

Step Seven - Adjust the Chainguide

If you’re running a chainguide, now’s the time to set it back up. Slide the rollers or sliders to their proper position. Most chainguides will have some kind of indicator to let you know where to set them according to your chainring size. 

Step Eight - Wrap it Up

Make sure you’ve tightened every bolt you’ve touched for this job. It doesn’t hurt to check the rest of the bike at this time, either. After you’re sure the bike is safe to ride, give the cranks a few spins in the stand to ensure nothing is rubbing or out of adjustment. It’s also a good idea to go on a quick test ride, especially if you were hunting down a creak or noise before doing this maintenance. That’s it, now go ride!

If you missed our General Drivetrain Maintenance, At-Home Tubeless Conversion, At-Home Fork Installation, At-Home Headset Installation, and At-Home Brake Bleed tutorials, check them out.