Bicycle Mechanics - Torn out rack mount

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View Full Version : Torn out rack mount


ToddDav
06-22-08, 01:37 PM
Hiya folks,

I slid out sideways going downhill on some road gravel and tore myself up a bit. The stitches are out and most of the scrapes and muscle problems are better. Luckily my body absorbed most of the impact, and except for a bent pedal cage and some ground down areas on the plastic of the shifters, my bike was fine.

The exception is that somehow I managed to tear the rear rack mount out of my seat stay. I mean the plug that the bolt screws into came out with the bolt. It is firmly attached to the rack, just not the bike.

Any ideas on how to get it back in there? The rack doubles as a child seat holder so I need it to be secure. I know a little about welding, and I am pretty sure that an acetylene torch will not help.

My thoughts were epoxy or find a shop that does some welding and pay whatever the ask. Anyone have insight or better suggestions?


ToddDav
06-22-08, 03:32 PM
Nothin' huh? It is an Aluminum frame, which I forgot to mention.

Any thing at all? Is my posting etiquette bad? Does my breath stink?

Indolent58
06-22-08, 03:50 PM
Your breath might stink, but that's not it. IMO, the answer isn't that straightforward. Forget about epoxy. If the rack mount has torn out I would first be concerned about the structural integrity of the seatstay, not just sticking the rack boss back on. Ideally a framebuilder should look at this, but very few of them work with aluminum so they would not necessarily have the equipment or expertise to repair it. Best to go to a weld shop equipped for Aluminum welding and see what they can do.


Large Filipino
06-22-08, 03:50 PM
Show us some pics,Todd. Just explaining it I can't get a mental visual.

ToddDav
06-22-08, 05:44 PM
Thanks for the clue Large. Here are a couple of pics:
http://picasaweb.google.com/toddmdavenport/UntitledAlbum/photo#5214854283837331266
http://picasaweb.google.com/toddmdavenport/UntitledAlbum/photo#5214854286487036130http://picasaweb.google.com/toddmdavenport/UntitledAlbum/photo#5214854286487036130http://picasaweb.google.com/toddmdavenport/UntitledAlbum/photo#5214854283837331266http://picasaweb.google.com/toddmdavenport/UntitledAlbum/photo#5214854286487036130
http://picasaweb.google.com/toddmdavenport/UntitledAlbum/photo#5214854283837331266http://picasaweb.google.com/toddmdavenport/UntitledAlbum/photo#5214854283837331266

the plug fits neatly into the hole with a little resistance. It actually stays in well enough to hold my pannier, but I do not trust it with my kid.

mechBgon
06-22-08, 07:26 PM
From the photo, it looks like that riv-nut took most of the damage. A well-equipped shop may be able to get a new one, preferably stainless steel, to stay put in the existing hole.

As an alternative, if your frame has a removable seat collar, there are replacement seat collars available which have threaded holes to attach rack struts to. It doesn't get much more secure than that :) They're available in 31.8mm and 34.9mm: http://74.8.32.132/nondealer/view.phtml?f_cat=SEAT+POSTS%3A+SEAT+POST+CLAMPS%3A+SUNLITE

http://74.8.32.132/product-images//x180/51864.jpg

Your LBS can get those for you if they look like a better solution. You may also need longer-than-normal extenders for the rack, such as Jandd's 16-inch ones (http://www.jandd.com/detail.asp?PRODUCT_ID=FEXT).

CrankyFranky
06-22-08, 08:08 PM
[QUOTE=ToddDav;6925076...I managed to tear the rear rack mount out of my seat stay. I mean the plug that the bolt screws into came out with the bolt. It is firmly attached to the rack, ...rack doubles as a child seat holder so I need it to be secure. [/QUOTE]
Um, welding would never do with Alum. frame. Go with MechBGone's seatpost widget answer and be glad you haven't broken a seat stay... or your child's head.

ToddDav
06-23-08, 07:51 AM
awesome. It is good to know that I have alternatives. Thanks to all!

DieselDan
06-23-08, 10:55 AM
If the stay is still sound, a P-clip would be the cheapest fix.