Bicycle Mechanics - crank

I was out riding last weekend and about 20 miles into my ride I started to hear a clicking sound on each downstroke of my right foot (clicking as when the chain rubs against the front derailer when not alligned properly) I stopped and noticed the center bolt of my crank on the chainring side was loose (shimano 105 triple). I tightend the best I could because I didnt have an allen wrench the proper size to make it secure properly. I rode back and apx 5 miles from my starting point I noticed it was coming loose again, I saw some guys working on their car and asked if they had an allen wrench, they assisted me and I got it tightend. The last 5 miles to my truck it still made a creeking sound. This sound was a bit different than the first, it sounded as if my pedal bearing was going out.
Could I have done some serious damage to my crank and BB?
Should I ride some more and try to determine exactly if its the pedal or the crank and BB?
Or should I just take my bike into my LBS and have them inspect it?
Thanks for any info in advance

Inspect I think, Prize-Guy I think it was mentioned he destroyed a bb in a VERY short time by not tightening the chainring bolts.
Can you pull it yourself?
Anyway-HOPE all is o.k.

Inspect I think, Prize-Guy I think it was mentioned he destroyed a bb in a VERY short time by not tightening the chainring bolts.
Can you pull it yourself?
Anyway-HOPE all is o.k.
Thanks, yes I can pull it myself...

I was out riding last weekend and about 20 miles into my ride I started to hear a clicking sound on each downstroke of my right foot (clicking as when the chain rubs against the front derailer when not alligned properly) I stopped and noticed the center bolt of my crank on the chainring side was loose (shimano 105 triple). I tightend the best I could because I didnt have an allen wrench the proper size to make it secure properly. I rode back and apx 5 miles from my starting point I noticed it was coming loose again, I saw some guys working on their car and asked if they had an allen wrench, they assisted me and I got it tightend. The last 5 miles to my truck it still made a creeking sound. This sound was a bit different than the first, it sounded as if my pedal bearing was going out.
Could I have done some serious damage to my crank and BB?
Should I ride some more and try to determine exactly if its the pedal or the crank and BB?
Or should I just take my bike into my LBS and have them inspect it?
Thanks for any info in advance

If it was my bike, I'd torque the crank arm on at 30 lb/ft and see how it goes. I wouldn't try it out farther away from my truck than I was willing to walk back. If it comes loose again, your crank is hosed. Unfortunately, that's a fairly common problem but it's usually the left arm that gets ruined. Crank arms are one of the things that I always use a torque wrench on. When left to my own devices, I consistantly undertorque them. I suspect that lots of other guys do too.

Yea , unfortunately I didnt inspect the crank prior to my ride, I noticed it loose about 20 miles into the ride...
I usually inspect everything before I journey out, but I just didnt check the crank for some reason on this day...
while I was riding everything was going good, then I shifted and heard the sound like when the chain is rubbing against the derailer, I bumped my shifter thinking it would adjust the problem and correct the sound, it didnt and when i looked down i could see my chainring crank was not where it was supposed to be, so i stopped and checked it and the allen bolt in the center was loose, so i tightened it the best I could with the allen wrenches I had, but they were too small, so thats when I turned back, I had no choice.. :(

Yea , unfortunately I didnt inspect the crank prior to my ride, I noticed it loose about 20 miles into the ride...
I usually inspect everything before I journey out, but I just didnt check the crank for some reason on this day...
while I was riding everything was going good, then I shifted and heard the sound like when the chain is rubbing against the derailer, I bumped my shifter thinking it would adjust the problem and correct the sound, it didnt and when i looked down i could see my chainring crank was not where it was supposed to be, so i stopped and checked it and the allen bolt in the center was loose, so i tightened it the best I could with the allen wrenches I had, but they were too small, so thats when I turned back, I had no choice.. :(

I know what you mean. Most of the multi-tools that you take with you on a ride lack an 8mm allen wrench - what's up with that?

I had the same problem just last week and with the same crankset (105 triple). Although both crank bolts worked themselves loose I had a 'clunk' feeling (no noise) through the left pedal under pressure and originally thought the bearings were gone in the pedal (as you did Bianchi_rider).

Since I built the bike myself it was a bit of a wake-up call to be more cautious in future. I've re-tightened them and haven't had any problems, including a long 100km+ ride. However before that ride I checked the tightness of every bolt on my bike, starting from the front to the rear (brakes and wheels as well).


If it comes loose again, your crank is hosed.

What part of the crank becomes 'hosed' Retro Grouch, the thread in the crank?

The crank brothers multi-17 mini tool I carry with me includes an 8mm hex wrench. I guess manufacturers' choose to leave it out due to weight or cost reasons.

If the cranks loosen enough to clunk or make noise, you are actualy changing the shape of the tapered square hole in the crank, or the splines of an ISIS or OctaLink BB. When that happens, the crank will no longer seat correctly, and will most likely refuse to remain tightened down. The only cure is crank replacement.

If the cranks loosen enough to clunk or make noise, you are actualy changing the shape of the tapered square hole in the crank, or the splines of an ISIS or OctaLink BB. When that happens, the crank will no longer seat correctly, and will most likely refuse to remain tightened down. The only cure is crank replacement. With a tapered square crank/BB, you can often see the damage. Pull the crank arm off with the proper puller, and look at the hole from the inside. If you see a little "shoulder" pushed up by the movement of the crank arm relative to the BB axle, you've started to round out the hole. You can sometimes get a part of a season out of it by reefing it down very tight, but you're only delaying the inevitable. Once that starts to happen, the roundness created by the looseness just allows it to round a little more each time you put force on the crank arm.

The BB destruction PrizeGuy mentioned was a different problem, related to loose chainring bolts.

I'm surprised that the crank bolts are 8mm Allen. I've always seen either 14mm hex or 6mm Allen. Or is this an Isis or Octalink crank/BB?

My campy BB has 8mm bolts. It has become more common, especially with integrated bolt/dustcaps.