Shinkers

Anyone use retaining compound on SRAM nylon press fit BB's?

Thanks.

02Giant 

Does SRAM recommend any?

fietsbob

whats 609? there are Loctite products to hold sealed bearings in, bearings used on cars trucks all sorts of industrial applications.

Are they a loose, fall in fit , now, do they make noises you don't like?

Shinkers

609 is a weak retaining compound to augment press fit.

Right now I have a wheels thread together unit that's creaking like a banshee. I'm trying a SRAM unit to see if it's any better.

Frame is relatively new.

Kontact 

609 can help with nylon cups - it will fill the gap between any materials. At the last shop I worked at we used it preventatively on Cervelo PF30 cups.

609 might also fix your current Wheels unit.



Otherwise, consider warrantying the frame, if possible. What kind is it? Some brands, like Specialized, released specific fixes for squeaky PF30s.

Shinkers

It's a Kona fatbike. I don't have any desire to continue using the Wheels unit. The last one I had wrecked the frame this one replaced, and the fit with my SRAM cranks is a little hinky.


I'm hoping the SRAM BB will solve my problems. SRAM recommends dry for their PF BB's, but I can't help thinking something to help fill up the space and hold the BB in a bit will be beneficial.


Just not sure if that should be 609, Teflon tape, pipe dope, or something else. 609 seems pretty widely used but Loctite doesn't advise it on plastics since it can make them brittle.

Troul 

Try plumbers putty.

xenologer

You'll probably need Locktite Primer
locktite doesn't set up on non-metallic materials on its own

Kontact 

Why? Loctite just hardens because it dries out.


I don't think there is any real reason to worry about it hurting nylon cups or the resin in CF. Both are extremely stable and nylon resists every kind of glue.


The goal here is to immobilize the cups, and they are already tight enough to need to be pressed in. 609 is thin enough to fit into that tight space and not stick permanently like a glue. Plumbers tape is great for quieting noisy threaded cups, but it is teflon and won't keep the pressed cups in place.

SkyDog75

Actually, that’s not the case for Loctite (and similar) threadlockers. From Loctite’s site: “Loctite® threadlockers cure in the absence of air and presence of metal ions. When assembling inactive metal parts, which are low in metal ions, the use of Loctite® primers are recommended to ensure proper performance of Loctite® threadlockers.” Iron, non-stainless steel, and copper are among the metals classified as ‘active’ in the Loctite product literature. Aluminum, both bare and anodized, is listed as ‘inactive’ and thus requires primer.

I don’t think 609 is classified as a threadlocker, though, so I don’t know if the above applies. There is a note in the product documentation that Henkel “generally doesn’t recommend” using 609 with plastics and especially thermoplastics. The wording is vague enough that it doesn’t specifically rule out using it for this application.

Shinkers

Well, the wheel's bb galled the shell on the way out so that pretty much decides things. I'll be using the Loctite since the shell is gouged now.


I do have the primer and will use some for insurance.


One thing I will say, is that I'll never again use a thread together bottom bracket in a press fit shell. This is the second time this has happened to me (this frame replaced another frame that this happened to).


Thanks for the info.


Edit: this documents my previous struggle https://www.bikeforums.net/bicycle-m...nternal-2.html

Revracer

Shinkers - I am in a similar situation as I have gone through two Wheels Mfg threaded shells as over time the spinning caused the shell to continue threading into the frame, one bent the flange all the way around and the second sheared the flange. I am now considering a replacement. I avoided the nylon because my original BB30 creaked regularly. Strangely I did not have noise with the Wheels unit and considered an aluminum press together unit. However, the reviews of the SRAM PF30 nylon look decent.