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Specific Loctite # for press fit BB bearings
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Lots and lots of discussion posts on using 'Green Loctite' to set press fit bearings. But there are many formulas for green. Which specific compound # is appropriate? Looking for something that doesn't require heat for removal. BB86 frame with alloy seats for the bearings in my case, using the Rotor 4130 bearings.
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Re: Specific Loctite # for press fit BB bearings [JesseN] [ In reply to ]
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JesseN wrote:
Lots and lots of discussion posts on using 'Green Loctite' to set press fit bearings. But there are many formulas for green. Which specific compound # is appropriate? Looking for something that doesn't require heat for removal. BB86 frame with alloy seats for the bearings in my case, using the Rotor 4130 bearings.

The green Loctite description can be a bit misleading. The Loctite used for these installations is retaining compound. Typically Loctite 641 or 609. They are are not heavy duty and are spec'd based on how much aof a gap they are intended to fill. Using Loctite Primer helps the compound cure.
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Re: Specific Loctite # for press fit BB bearings [JesseN] [ In reply to ]
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Just press them in with grease unless you have had creaking problems
Once you head down the glue it in path your life is much more difficult.
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Re: Specific Loctite # for press fit BB bearings [JesseN] [ In reply to ]
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Basically SummitaK nailed it.

Use this: Loctite SF 7649 (Primer). Then use this: Loctite 609.

Boom done.

Piling on the grease will silence the creaking temporarily. But your still running your BB in an "untrue" manner. ie....it's still rotating in an environment that has micro gaps. The Loctite 609 will fill these gaps in properly, as it was developed and designed to do in many bearing environments. The Primer SF 7649 will speed up cure time as well as insuring the 609 and subsequent bond is correct and pure.
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Re: Specific Loctite # for press fit BB bearings [JesseN] [ In reply to ]
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I recently used Loctite 609 on an older bike. The bearing was fitting loosely enough that it would spin in the shell. I feared I was going to have to trash the frame but decided to give this a try and it has worked great. This might be a little bit of overkill for just a creak but if you are in real trouble, give it a try. I ahve not tried to remove the bearing yet so can't comment on that but I think it requires some heat.

As mentioned, Loctite 609 Retaining Compound is not a thread locker like regular Loctite you'd use on a bolt but are specifically designed to fill gaps around bearings and from my research, it appears to be widely used in industry and motor repairs when setting bearings. The stuff dries super hard but it is thick and not runny so it will fill gaps. A few bike companies recommend it.
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Re: Specific Loctite # for press fit BB bearings [STP] [ In reply to ]
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Looking back at the manual Rotor provides they recommend 641 specifically. Thanks all.
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Re: Specific Loctite # for press fit BB bearings [JesseN] [ In reply to ]
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Just browsing the Loctite website and 609 says it is for metal parts in the technical information. 641 says it is for metal and plastic and describes it as medium strength.

Unless anyone knows more, I'd read that as 609 is high strength. So if I had aluminium cups in the frame I might use 609 or 641 but if it was carbon fibre I might go for 641 just because it sounds safer. I'm sure both are fine.
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Re: Specific Loctite # for press fit BB bearings [STP] [ In reply to ]
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How in the world do you clean the 609 off the carbon if you need to remove bearings? I've used this stuff in the past on non bike parts and it works well, but it's required a torch to remove the bonded parts! Obviously a torch and carbon don't mix.

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Re: Specific Loctite # for press fit BB bearings [JesseN] [ In reply to ]
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Personally after having issues removing a PF30 bb from a frame after just using grease and resorting to a large hammer I would never using any bonding material. I am now a Wheels bb convert and can just screw the shell in and out and creaking issues are no longer as well...

http://wheelsmfg.com/bottom-brackets.html

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Re: Specific Loctite # for press fit BB bearings [Shambolic] [ In reply to ]
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Unfortunately not an option for my particular frame/crank combo.
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Re: Specific Loctite # for press fit BB bearings [OddSlug] [ In reply to ]
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OddSlug wrote:
Just browsing the Loctite website and 609 says it is for metal parts in the technical information. 641 says it is for metal and plastic and describes it as medium strength.

Unless anyone knows more, I'd read that as 609 is high strength. So if I had aluminium cups in the frame I might use 609 or 641 but if it was carbon fibre I might go for 641 just because it sounds safer. I'm sure both are fine.

The material either side of the gap is a concern for curing. Some ferrous metals will cure without help while some metals and non-metallic materials need to be primed with activator.

641 is typically described as low strength or controlled strength retaining compound intended for parts to be disassembled later. 609 is medium strength or general strength, also intended for parts to be disassembled.

Loctite has a number of high strength retaining compounds. 680 seems to be the most common.

Here is a general Loctite retaining compound guide link: http://na.henkel-adhesives.com/..._Solutions_Guide.pdf
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Re: Specific Loctite # for press fit BB bearings [Shambolic] [ In reply to ]
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Shambolic wrote:
Personally after having issues removing a PF30 bb from a frame after just using grease and resorting to a large hammer I would never using any bonding material. I am now a Wheels bb convert and can just screw the shell in and out and creaking issues are no longer as well...

http://wheelsmfg.com/bottom-brackets.html

That's a great option if you have a PF30 that creaks, but has otherwise tight tolerances. I tried this BB on a looser PF30 frame shell and the side force from clamping down wasn't enough to overcome that the BB went in by hand w/o the need for a press. Measuring the WMFG BB with a caliper I found that they make these with a slight taper to the shell with the largest diameter at the outside still slightly less than the SRAM PF30 spec.

I've been able to avoid gluing in PF30s by using BB's with outer diameters that are near spec (Chris King) or slightly oversize (Kogel). If using a 24mm crank is an option then the Praxis PF30 conversion BB, which has an expanding collet on one end, will typically get the job done.
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Re: Specific Loctite # for press fit BB bearings [SummitAK] [ In reply to ]
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Update, knocked my bearings out and re-installed with a thin coat of 641 on the frame shell before pressing back in. It was obvious the shell itself is not quite round. Did not use any primer. Left to cure for 24 hours before installing crank. Did a short ride this evening. Totally silent while seated. Out of the saddle have some minor clicking above 400w. Not perfect but I think good enough.

As an aside, loctite 641 is surprisingly tough to get on Amazon. Most any option I saw was shipped from India with 'free one month shipping'. Ended up buying from Grainger and it wasn't cheap but had it in a day and now I can ride again without wanting to throw the bike in a ditch.

Now I'm sure I've jinxed it.
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