# Best practice for bearing mounting



## arnea (Feb 21, 2010)

I'm overhauling my Smuggler and need to replace the pivot bearings. Transition doesn't have "official" guide for bearing replacement, so I looked around.

Everybody seems to suggest that bolts must be greased and blue Loctite must be applied to bolt threads.

Some companies (Liteville, Santa Cruz, Marin) suggest that bearings should be mounted with retaining compound (e.g. Loctite 641). Others suggest dry mounting of bearings. I would like to use retaining compound, to avoid possible corrosion and seizing - are there any arguments against this?

Marin also suggests (https://www.manualslib.com/manual/824077/Marin-Rift-Zon.html) that anti-fretting compound must be used between bearing faces and links. Do you think it's good practice? I happen to have this Castrol compound they refer to.


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## One Pivot (Nov 20, 2009)

I have a 10 year old Kona dawg that's definitely seen rain, mud, salty sea water, and snow. Bearings were pressed in with a bit of grease. Frame is still perfect. 

I'd use plain grease and nothing else. You really don't want to be chemically retaining those bearings, they might need to come out later. I'm not a fan of heating frames to breakup compounds.


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## customfab (Jun 8, 2008)

Here's a completely opposite opinion, bearing retainer is insurance and it's better to have it and not need it than need it and have to add it later. It's cheap and easy to remove by warming them up if need be. You can direct the heat at the bearing that you're going to replace to minimize the heat into the frame which is a good idea. 

You can also measure it to see if it's necessary. If the bearing bore is eccentric or gouged at all I would put bearing retainer on. The bore of the frame should be .01mm under the OD of the bearing for a tight interference fit. If it's the same size or bigger I would definitely put retainer on it. Loctite 600 series is a great option.


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## Ratt (Dec 22, 2003)

Are these slip fit bearings? If press fit, I guess I've been doing it wrong, I am like One pivot, i just grease em.

I practice a slow escalation of force. I start with grease. If it comes loose, I move on to a little bit of blue locktite. If it comes loose, I actually clean the grease off and try a little bit of blue again, then a lot of blue, then red.


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## WHALENARD (Feb 21, 2010)

+2 for retaining compound. I've never found it an issue to removing bearings.


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## arnea (Feb 21, 2010)

Thanks for advice. Meanwhile I also asked from Transition and they said that they use retaining compound during assembly. 

Those bearings are definitely press fit, not slip fit. The bearings felt notchy when in frame, but most of them were smooth when pressed out. This seems to indicate that the bearing bores are slightly undersized. I wait until my Enduro MAX bearings show up and try how they fit. If they become also notchy then I should probably polish the bearing holes little bit.

But have somebody used anti-fretting paste instead of grease on bolts? Since the bolts are not supposed to move relative to other parts (bearing inner races, spacers, swingarms) it sounds like a good application for anti-fretting paste.


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## cjsb (Mar 4, 2009)

The last time I pressed in bearings to frame was on my old Heckler. I used just normal grease, like the blueish stuff in the Park tube. I did not care for the press/removal tool from SC, so got out King Hub tool, which did capture for removal (allowing for easy whack-out), and pressing in a breeze. For pressed in bearings I wouldn't consider anything but grease, but does not mean I am right either. I recall so many threads on MTBR with PF BB where it seems one is "supposed" to used lock tite or other compound? To me, the use of the latter means it wasn't sized precisely when made, but I am no expert. 


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## MikeBurnsie (Jan 19, 2011)

On my Transition Patrol I use bearing adapters from RRP and a bearing press handle from RWC, works fantastic. I use just a little bit of slick honey for install. I did notice that my bearings, not all, are notchy in the frame but smooth otherwise.


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## Grassington (Jun 24, 2017)

arnea said:


> But have somebody used anti-fretting paste instead of grease on bolts? Since the bolts are not supposed to move relative to other parts (bearing inner races, spacers, swingarms) it sounds like a good application for anti-fretting paste.


Yeah, I'm a big fan of anti-fretting paste. I first came across it when replacing the pivot bearings for the first time on a 2001 Marin Attack Trail: thought I'd better RTFM before starting and it's a good job I did as Marin stated that not using anti-fretting compound on key frame parts would invalidate the frame warranty. The product they specified wasn't available in the UK, so I used Castrol Molub Alloy (formerly Optimol) Paste White T. I figured if it was good enough for BMW motorbikes, it was good enough for Marin.

If the part isn't meant to move then I use anti-fretting paste in preference to grease because aside from the superior wear-reduction qualities it's also incredibly water resistant. I've had AF paste fingerprints on my frame that have resisted many months of dust, mud, being scrubbed with detergent and then hosed down. It's not completely magic though, and despite my enthusiastic use of it I've had fretting damage on the fork steerer tube from the top split collar on the headset, and on a Hollowtech crank axle where I stupidly didn't get the BB frame tube immediately chased-and-faced when moving over from ISIS BBs (now sorted). I also had a front hub bearing boss swage itself bigger from years of hard front braking (this also stress-damaged the rim, mostly on the rotor-side nipple holes).



MikeBurnsie said:


> On my Transition Patrol I use bearing adapters from RRP and a bearing press handle from RWC, works fantastic. I use just a little bit of slick honey for install. I did notice that my bearings, not all, are notchy in the frame but smooth otherwise.


The notchiness is probably due to the pivot bolt being a bit too tight. I've sometimes noticed this even when they're set to the spec'd torque - if this happens, just back it off a tad until the notchiness goes away. To be safe, always use a new Nyloc nut (add a bit of threadlock compound too for the whole belt-and-braces safety factor).


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## arnea (Feb 21, 2010)

Thanks for answers.



Grassington said:


> The notchiness is probably due to the pivot bolt being a bit too tight. I've sometimes noticed this even when they're set to the spec'd torque - if this happens, just back it off a tad until the notchiness goes away. To be safe, always use a new Nyloc nut (add a bit of threadlock compound too for the whole belt-and-braces safety factor).


In case of Transition the pivot bolt cannot cause the notchiness. Then notchiness is there even without the bolt. You just have to press it into the frame.


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## MikeBurnsie (Jan 19, 2011)

^^^ The notchiness is there like arnea said, without the pivot bolt.


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## Grassington (Jun 24, 2017)

arnea said:


> Thanks for answers.
> 
> 
> Grassington said:
> ...


OK, it wasn't originally clear that the fitted bearings were notchy without the pivot bolt. Have you got calipers to measure the bearing OD and housing ID? If one of those isn't out then a different brand of bearing might see you right. For the same size of bearing it's possible to have different degrees of bearing float - for instance a bearing designed for high speed use will run a little loose at room temperature and the slack will only be taken up once the bearing is running at its designated high operating temperature. If your current bearing and bearing housing are dimensioned to spec then it may be you have the opposite problem to this, i.e. you need a bearing with a bit more slack between balls and races so the balls don't bind when the outer race is compressed in the frame housing.


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## arnea (Feb 21, 2010)

Bearings arrived and I mounted them. I bought YS-BT1112 bearing removal and insertion tool. I don't recommend this. The removal adapter works ok, but insertion part does not keep the bearing straight. RRP or RWC installation tools are probably much better.

The Enduro Max Black Oxide bearings look really good when pressed in. Only one one bearing felt bit tight when installed. I removed it and pressed in one of the old bearings again and then removed it and reinstalled the new bearing. This removed little bit of metal and bearing moved more freely.

I used Loctite 641 compound for mounting the bearings and Castrol anti-fretting paste for bolts. All threads got Loctite 243 threadlocker.


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