Safe to install rivnuts in frame?

[bikemaniac]

Hi,

Does anyone have experience with installing rivnuts in bicycle frames? A rivnut is a special rivet with an integral threaded part which can be installed using a tool similar to blind rivets. I would like some feedback from people who have done the great divide or similar without any failures. Explained differently: Can they take the beating? :-).

Lucas

[tdurack]

No experience myself but this guy does it all the time:

http://gypsybytrade.wordpress.com/2013/04/26/rivet-nutting/

[murf]

I've done it several times to many frames and even a seatpost. The tool is pretty cheap and it comes with a few rivnuts.
I loaned the tool to a friend and never got it back bit I watched a video on you tube that show a super easy way to do it with a bolt and nut and that's what I use now.

When drilling the frame on the underside of a down tube is quit simple , where it gets tricky is when its inside the front triangle and you don't have enough room for the bit and drill length to drill the hole straight.  To solve that I went to harbor freight and bought a right angle attachment for $15.

To get the bit to stop wanting to wander when starting the hole I use a file to make a flat spot on the frame to start the bit.

Hope this helps and good luck.

P.s. most bike shops will do it for $15-$20

Sent from my SCH-I535 using Tapatalk

[pro_out]

I've done it many times, no problems. I would recommend de-burr the holes.   Burrs cause more stress to be concentrated at the edges of holes, decreasing resistance to fracture and shortening fatigue life. 

[Area54]

Yep, installed plenty over the years. There are quite a few different types of rivnut (also called nutsert, polynut) but bascially you want a design that has a pretty good shoulder on the outside face , as well as a large riveted shoulder inside the cavity. They come in different lengths to suit different thicknesses of material. You can make the tool yourself.

Alloy and steel rivnuts. You want steel for anything that is carrying heavy stuff, prep the holes with some anti-corrosion paint too when you install the rivnuts. Drill the holes just on size or slightly undersize, then tapfit to improve the solid fit.

[danimal]

I have been a professional mechanic for several decades.  I have installed a lot of riv-nuts, including on my own bikes.  You should know that it will void most any warranty.  You should consider the location, material and likely stresses carefully.  In a couple of cases of the very lightest of aluminum frames coupled with poor choice of location, out of fear for shop liability, I declined to do it.  I would never put one in a fork.  Make darned sure the riv-nut goes in tight to the tube.  Not just the hole size, but the compression you apply with the tool.  The vast majority of riv-nuts that I have installed were replacements for factory nuts that weren't tight enough and spun when the owner tried to pull a over-torqued or corroded bolt.  This creates a challenge for removal, some much tougher than others.  To help prevent that trouble, use anti-sieze or grease and get a little under the head of the bolt as well as the threads.  A washer under the head also helps with this.  I like steel riv-nuts more.  Occasionally, the force necessary to get an aluminum one tight enough not to spin, the threads can get pulled out.  And I would second all the pointers already given.  Not trying to discourage, they are often a very handy solution.  It's just that I have also seen them cause considerable trouble and expense when used without proper care.

[mtntraveler]

On a related topic
Is there a good fix for a riv-nut that starting to work loose.  The first thing, I thought was to try to retighten the riv-nut, or should I drill it out and start over?

Thank for the info 

[danimal]

I have re-tightened them many times.  Easier with the proper tool.  But, plenty doable with a nut and bolt.  If the brand is one that a local shop carries, I would go by there and see if they wouldn't consider snugging it up for you.  It takes just a minute or so and in any shop I have worked in it would have been considered under the frame warranty.  Good luck.

[ROADHOG]

McMaster Carr online has nuts.

If for a bottle cage try West Epoxy Gflex and a good nut: permanent and waterproof.

calculate what weight spectrum your testing with online calculators.

[ROADHOG]

 
 WITH EPOXY, surface prep and providing surface area...nuts washers sheet metal screws with washer heads...then not bashing the assembly...waterproofing with a linseed film is AAA.

discussion is ongoing:

https://www.google.com/#q=alternative+to+rivnuts