Bicycle Mechanics - Loose bottle cage boss on an Aluminun frame

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yannisg
02-21-12, 06:24 AM
On my Giant OCR (Aluminum frame) the upper front bottle cage boss has detached from the frame. In the pass I used Super glue to keep it in place an avoided using a water bottle in the front cage. I just had a small pump base with the pump underneath the cage. In the beginning, the cage was steady, but eventually became loose.

Does anyone had a recommendation how to secure the loose boss permanently on the frame?

Thanks,
YannisG


AEO
02-21-12, 06:34 AM
take it to a bike shop that deals with giant bikes. They should have a tool that will fix the rivet.

AlphaV
02-21-12, 06:44 AM
JB Weld. It's a 2 part adhesive for securing metals. Most super glues are crap for attaching metals. It's usually found in automotive repair stores.


BikeWise1
02-21-12, 06:53 AM
JB Weld. It's a 2 part adhesive for securing metals. Most super glues are crap for attaching metals. It's usually found in automotive repair stores.

Far easier to fix the problem with a rivnut tool, and as has been said, a shop should have one. We see this quite often.

I don't see how JB Weld would work anyway. This rivnut is probably spinning in its hole, not off the bike. JB ain't thin, and getting enough where you needed it will be difficult.

Just get it fixed the right way. The right tool can tighten it up.

yannisg
02-21-12, 07:14 AM
Thanks for yr responses.
What is a rivnut tool? How does it tighten the loose boss? The boss is completely out of the frame. It came off when I removed the cage from the frame. I would assume that I would need a new boss and the tool would crimp it on to the frame. However, I worried that the hole on the frame is already worn too big.

YannisG

BikeWise1
02-21-12, 07:26 AM
Your cage bolts were likely overtightened, or installed without grease at some point. You need a new rivnut installed. There just isn't sufficient surface area for a real secure bond. Get it done right. I can't tell about the condition of the hole, but I've never seen one worn out....

bradtx
02-21-12, 07:28 AM
YannisG, The rivnut requires compression to tighten itself to the inside of the frame tube. The rivnut compression tool can be substituted with a wheel hub, spacer and the quick release. As you need the rivnut anyway just go to a LBS and have them install one, it probably isn't too expensive.

Brad

HillRider
02-21-12, 07:52 AM
If the OEM Riv-nut pulled out of the frame I would expect the resulting hole is now oversize and won't retain a new Riv-nut of the original size (M5x0.8) and you may have to go up a size (to M6x1.0) to replace it. I agree that taking the bike to an LBS is the way to go for this repair.

FBinNY
02-21-12, 08:38 AM
A Riv-Nut (http://www.cardinalcomponents.com/fasteners.htm) is like a Pop-Rivet that instead of having a solid rivet has a threaded center which acts as a nut would. It's installed from the outside and the inner flare is done by drawing the threaded portion back which buckles a weakened area into a rivet head. Riv-nuts are the most common of attached threaded bosses to tubes where brazing or soldering aren't an option.

The nice thing is that they can be drilled or filed out and replaced. However if torn out can enlarge the hole making replacement more complicated, though still possible.

yannisg
02-21-12, 11:32 AM
Thank you everyone for yr responses.
I'll contact the LBS for a revnut installation.
YannisG