Bicycle Mechanics - Loose bolts
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When I was giving my bike a bath yesterday I noticed some of the bolts on my bike were loose. It's the ones that hold the bottle cages on. I tightened them back up with the allen key set that is in my bike bag so I think they are OK now. But now I'm a little worried there might be other bolts loose. I don't have all the right wrenches. Do you think I should take it to the bike shop?
I've been riding on a lot of rough roads lately. Could the vibrations cause them to rattle loose?
That’s what happens when one seeks out the bumpy roads “SMILE”. Most modern bikes can be maintained (almost) with just Allen wrenches. But if it’s been awhile since your bike has been serviced, then a tune-up at the LBS sure wouldn’t hurt. The headset and wheel bearings (which do require other wrenches) may also need adjustment. :D
Get some Locktite and put a bit on the threads of the waterbottle screws and it should minimize this. Not cheap but useful stuff. Highly recommended for cleat screws and jockey wheel screws also. A set of small metric wrenches, basically 8, 10 and 12mm cover almost all the nuts. A 2mm, 4mm, 5mm and 8mm hex allen wrenches get all the allen screws. You are up to maybe $15 at this point. Add a pedal wrench, which doubles for the wrench needed to torque your BB remover tool and that is about it. A few bikes have 6mm allen
sockets and my old Cinelli stem needs an odd ball 7mm. That covers the basics. Adding a casette and BB removal tools, a crank puller and chain tool, and chain whip
and voila you have a tool kit. The under seat bike bag should include a 5mm
allen wrench as it covers most of the bolts on Shimano groups. Get the basics, get used to checking the bolts yourself and the bike will be that much less mysterious. steve
07-15-03, 08:48 PM
Be careful with loctite, use only blue (242,243). The red loctite requires heating to release and is so strong that you can snap the head off a bolt set with it.
Thanks for the help everybody! I think I better take it to the bike shop. :)
Rev Chuck: I think the locktite color scheme is oriented toward stud size bolts that have a lot of thread area. Smaller (5mm) size screws don't have enough surface area to lock up in this way even with the heavy duty version which is rated at 6-8 kpsi. Screws under .25 " in diameter will for the most part be removeable manually even with the highstrength stuff. Their literature discusses this obliquely. Of course a 5mm screw 20mm long slathered up probably will have enough surface area to lock up but not on the short thread pop screws used for bottle cages. Steve
07-16-03, 09:13 PM
Possibly, but when I was a power equipment tech, the cylinder base bolts(3mm) on Echo twostroke motors were blue loctited and if you did not heat the flange they would snap about 25% of the time. This does have something to do with the thickness of the clamped surface, the thicker it is the more wind up the bolt has before the threads break loose.
If a bolt is torqued properly it should not loosen, but I have found this to not be allways true.
Mitzi, when you go to the bike shop, ask them to recommend a good multitool for your bike. You should be able to get one for under $20. That way if you notice something loose you can tighten it up right away. Even if you are not interested in performing maintenance on your bike, a multitool in your seatbag can mean the difference between riding home and walking.
07-18-03, 07:33 AM
If a bolt or nut comes loose, the common reason is that it simply was not tightened when it was assembled. Tight bolts do not as a rule come loose. The best thing to take on a ride is the knowledge that your bike is well assembled. It is the tension on the threads when the bolt is secured that keeps it from coming loose.
See Torque Concepts (http://www.parktool.com/repair_help/torque.shtml)
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