[Closed] Creaky BB

Don't think you can fit a threaded BB into a press fit BB frame that easily, if at all. Maybe there is an insert available, but I've never heard of it.

Easiest option is just get like for like

Sorry I meant threaded press-fit. One like this.

I'm just not sure of the correct size I'd need.

Ah, gotcha. One with a threaded centre tube.

Sorry can't help with sizing, but I'd guess at 89.5 - 92mm

This may work if it’s PF92

Driveline Threaded-Press Fit Bottom Bracket for BB86/BB92 Frame to Shimano 24mm Crank for MTB/Road Bike https://www.amazon.co.uk/dp/B0831N1TST/ref=cm_sw_r_cp_api_i_Q3.jFbV2DSJPV

Recently got one and have been impressed.

The best BB to fit would be the hope BB as it has a cylinder which screws the two sides together. You need a special tool to do it though (£50), or you can get a cheep tool off eBay. The key thing is prepping the frame and cups with assembly compound, with out this the cups can move in the frame and that is what will cause the creaking. GMBN Tech (doddy) YouTube channel did a really good edit about fitting press fit bottom brackets.

link to ebay thing https://www.ebay.co.uk/itm/Hex-Tool-for-Hope-PF41-PF46-Press-Fit-Bottom-Brackets-Allen-Key-31mm-25mm/132629856491?var=431964007717

Thanks for the info!

The problem I have is I have no idea what size it is.

Post up a couple of pictures, hopefully one of us will be able to point you in the right direction.

I fitted a wheels manufacturing threaded press-fit last month after posting a thread up.

Wheels manufacturing

Uses a standard hollowtech 2 tool for fitting, not a £50 use once tool. Replaceable bearings without needing to remove the cups either.

A couple of pics.

The only writing is ‘DO NOT DISASSEMBLE’ which is exactly what I’m trying to do. 😄

Email Giant?

I’ve emailed Giant but I’ve had no response yet.

The internal diameter of the BB shell will be 41 mm and the BB shell width will be either 89.5 mm or 92 mm. Depending on which BB you get you may need some axle spacers to get the chainline right. I had a low rent plastic Shimano RS500 PF BB on my gravel bike which lasted 116 miles before failing (baffles me why you'd want to make a BB from plastic!), I fitted a Hope PF41 BB which has a thread together tube to lock the cups in place, is made of metal and is much improved but required some spacers to get get the chainline right. Wheels Manufacturing make spacers in 0.5 or 1 mm widths.

As your frame is alloy you should just need to apply grease to the BB cups and frame BB shell when fitting.

Just been researching this for my Commencal. Unfortunately as there is an obstruction in the BB tunnel I can't fit one of the screw to itself solutions.

My NDS bearing popped out very easily so I'm looking at gap filling bearing retainer type stuff for mine but all of the advice I've read/watched is to use loctite 609 or similar for assembly and never grease as grease will aid movement between cups and shell and it is this that causes the creak noise. The aim should be to ensure the cup and shell are fit together in such a way as movement is prevented.

As alloy is relatively soft it will deform over time and you will get tiny gaps between cups and shell this is where the retaining compound comes into play as it fills these voids with hard material to prevent movement.

The do not disassemble message in the pics above is in regard to separating the bearings from their nylon cups not removing the bearings and cups from the frame.

smokey_jo, I get what you say ref not using grease, though thats what the instructions for the Hope BB said to use.

definitely don't use grease, use the retaining compound

Giant have responded to my email.

The bottom bracket specification we have listed for your bike is:

BB.Set BB-MT800-PA FOR MTB "W/O THREAD" R&L BEARING W/INNER COVER

For your information, this can be ordered through any Giant retailer using part number 1288-BBMT800A1

I ended up going like-for-like to keep the cost down as I bought the removal tool and a bearing press.

From what I've read and seen on youtube, you only don't use grease on carbon frames. Mine is Aluminum so it should be fine to use grease.

So I put in the new BB using a bearing press and used finish line Teflon grease on the cups.

Tested it out with a short spin up the road. No creaks. Happy days.

First proper ride tonight and the first 30 mins were bliss, quietness. Then it started... and gradually got worse. By the end of the ride it was probably worse than it’s ever been. 🤦🏻‍♂️

Any ideas?

It was never the bearings creaking it was the cups moving in the frame as the shell had deformed over time, you then added grease which allowed the new cups to move in the shell again.
DSWDWY

The bearings are sealed in the bottom bracket. I replaced the whole bottom bracket.

The cups are the part of the bottom bracket which the bearings sit in, the plastic housing. These are the parts which need a tight interference fit with the frame. As the bearings are sealed and sit within the plastic BB cups there is no need to apply grease. What you want to happen is for the plastic cups to be gripped tightly in the metal shell, by adding grease you've promoted rotation of the plastic cups within the frame.

The problem you now have is that the nylon cups have deformed already (as they are designed to do) when you installed them so removing them and reinstalling isn't likely to improve matters, in fact it will probably make it worse.

I did the same as you the first time and ended up binning the BB. A new BB has not solved my creaking as the rotation of the cups in the frame has deformed the shell too much. You may be lucky but I expect you'll end up going for one of the screw together inserts before you're finished solving this.

Bit concerned about the striations in the non driveside of the existing BB, is the crank rubbing against the shell?

You're not supposed to use grease between the cups and frame because if the cups rotate in the frame they'll wear it away and you'll no longer have a nice round hole (although Trek tend to have problems making it round in the first place)

I've removed it and cleaned the frame and outer shell of the cups.

A quick spin up the road and it's quiet again. I'll take it out tomorrow for a proper ride to see if it's any better.

If it's still the same I will have to try a threaded push fit BB and pray that solves it.

Good decision, fingers crossed for you.

I have just used a smear of blue lipstick loctite 248 on my press fit BB92 GXP SRAM, last one lasted two years and knocked out OK with same install method.

Sorry, forgot to reply earlier in the week. Looking at your photos it's an outboard cup.
With the cups out measure the internal diameter of the shell and the width. Only other measurement you'll need is the crank diameter (looks like 24mm from the photos) and that'll be enough to select the correct threaded push fit unit.

How did it go Chuck?
The retaining compound was unable to fill the void on my deformed shell so I've gone full nuclear with Epoxy resin to fit them this time. My next move will be riding on my own with noise cancelling ear defenders!

I went for a local ride Saturday morning and it was creak free for about an hour until my ride was cut short. I manged to slice a hole in my rear tyre on a rock. Multiple attempts with anchovies unfortunately wouldn't plug it. I did have a tube in my bag but I decided to push it home in the sunshine and reflect on why I loved mountain biking.

Second ride out and it's creaking again.

I'm going to have to suck it up and get the thread-fit BB.

This one should do the trick.