Originally Posted by
dave_100
Hi all
So the bottom bracket on my bike keeps coming loose, please see 5 second video here that shows the problem:
http://www.youtube.com/watch?v=DrKmwyHm-Xk&hd=1
I took it to the shop and they tightened it, which didn't take long at all, however I don't think they tightened it that well because it has started getting loose again already after only 6 miles riding.
I didnt see them tighten it so I'm not sure what kind of tool they used. I have researched a bit and have found different answers, some say you need lots of special tools, some say just a 32mm wrench,
The below pics show a close up of the bracket, please can someone help me with which part needs tightening, and what tool I would need to tighten it? I'm thinking if I get the right tool it would save taking it to the shop each time and I can give it a proper tighten.
The photos have labels on, so if you can specify easily, eg: A or B for example.
From one side:
http://img200.imageshack.us/img200/3906/dscf2351o.jpg
http://img35.imageshack.us/img35/2594/dscf2350copy.jpg
On the other side:
http://img823.imageshack.us/img823/6960/dscf2352f.jpg
The metal part label C is on this side of the bike, just behind all the plastic shielding:
http://img709.imageshack.us/img709/2963/dscf2353i.jpg
So yeah, 2 questions really, which tool is needed to tighten the bracket on this bike, and which part do I need to tighten?
Hope this helps, please let me know if you need any more info to resolve
After you've checked the drive side, making sure it's tight, and you don't need to service the bottom bracket (clean, change bearings, etc.) just adjust it, you only two tools and no need to remove the cranks.
This one fits the 3-notch lock ring.
http://www.parktool.com/product/cran...t-wrench-hcw-5
This one fits the adjusting cup.
http://www.parktool.com/product/adju...-wrench-hcw-11
This is a nice tool because it's thin enough to fit between the adjustable cup and the crank arm.
Adjusting these takes quite a bit of patience and good feel. Turning the 3-notch lock ring counterclockwise loosens it, giving you access to tighten or loosen the adjustable cup.
After you've adjusted the cup and start locking down the ring by turning it clockwise, the cup may start to turn along with the ring, effectively make it tighter, screwing up the initial adjustment. If this happens, just adjust the cup a bit loose before tightening down the ring to make up for this added travel.
Don't be surprised if you have to go through this procedure four or five times before you get it right. Sometimes you'll have to hold the cup adjusting tool firmly in place with one hand, preventing it from turning while you tighten the lock ring with the three-pronged tool in your other hand. Take care using the lock ring tool, making sure all three prongs of the tool are perfectly engaged in the three notches of the ring. If the ring is made of softer metal, it can get stripped. It's a very narrow fit, and takes a steady hand to remain engaged while tightening. The tool wants to twist left or right, slipping off the notches.
If I get a unit that is comes loose, I'll be sure to grease the threads of the cup, leaving the last few exposed millimeters of the thread dry. I'll then apply blue thread locker to the threads that are left exposed outside of the frame's bottom bracket shell where the lock ring will be threaded. This can make adjustment more difficult for the reasons above, but it will ensure the ring won't loosen.
I rarely use a hammer on a bike or tool, but I do find using a hammer on the lock ring tool works well to really cinch it down. This takes a very steady hand with constant clockwise pressure to prevent the tool from slipping off the notches as the hammer hits the other end of the tool.