Crank Attachment to BB

[Rapid Tourist]

For all the mechanics out there:

I have been doing the work on my fixed gear and maybe I'm doing something wrong. Please help me out if you can.

I have a Phil Wood BB (square taper, ti spindle). Periodicaly the screw which holds the cranks to the BB becomes loose which causes the cranks to wiggle on the BB spindle. I just get off the bike and tighten the screw. I'm nervous about this because it strikes me that if the cranks fly off the bike during a ride I've got a big problem. :bike:

Should I use loctite to fix the screw to the BB spindle?? I've avoided this because its a ti BB spindle and I don't want the screw to chemically bond to the BB. Any ideas for how to tighten this permanently?? Would a longer screw help??

[DfCas]

http://draco.acs.uci.edu/rbfaq/FAQ/8f.11.html

Its from the FAQ on rec. tech. Since your arms may be toast,you might want to try a non permanent type of loctite.If you are fairly light,say under 150 lbs,you may get a lot more use out of them.

On a seperate note,as much as I like ti,I've heard mostly bad stuff about ti spindles.

dan

[Jeremy]

This has been mentioned before, but it is important to note that there are two square taper interfaces: Campy and JIS. It is important to know that the cranks and bb share the same taper. It is possible that your crank arms are damaged in which case, they will not stay tight, and will need to be replaced. I agree with Jobst Brandt that the spindle interface should be lubricated. However, it is also important that the threads on the crank bolt are lubricated prior to installation. If the threads are dry, a torque wrench will give you a false reading of crank to spindle compression because a torque wrench measures the force required to turn the bolt. If the bolt is dry, it will bind under load before the crank is properly tightened to the spindle. A torque wrench does not measure how far the bolt has been tightened, but only the force required to continue tightening it. I also lubricate the flat surface on the inside of the bolt where it compresses and turns relative to the crank arm to eliminate the possibility of galling/binding at that point. I have never seen a properly installed square taper crank that needs loctite on the crank bolts to prevent them from loosening. Although, I have seen plenty of damaged crank arms due to improper initial assembly.

Jeremy

[David Kirk]

I'm sorry to say that it sounds to me like the crank arm is toast.

Can you see if the crank is pushed past the tapered part of the spindle when tight? Or is it possible that the bolt bottoms out on the spindle when tightened?

Dave

[Smiley]

Tourista , Octalink Baby , what are you doing shelling out that kind of Jack for Phils stuff with Ti no less , geez I guess I taught you nothin . I agree with Kirk , I have never had a problem with a taped BB axel , maybe your just not tightening it enough .

[Too Tall]

What Smiley said. Have it properly torqued once AND have a second set of eyeballs look at the setup....could be as simple as NOT having a washer behind the bolt. If it's you doing the torque job using a 6 inch wrench I think you'd end up doing a carwheel not the bolt!!!! Pipsqueek!!! bannana

PS - Smiley, Octalink is the anti-christ and clinchers su$

[christian]

I'm with you. Octalink is the devil.

- Christian

[Bradford]

Yeah, I'm with you two. I had to pull my splined crank off yesterday and much to my disgust, it came of easily and went back on just as easily. Who needs cycling products that work exactly the way the are supposed to, are easy to use, and perform flawlessly.

I think we all need to go back to sqaure tapers, down tube shifters, and plastic bar tape. I hate progress, especially when it works so well.

Cycling is so much more fun when you have to have a lot of skill just to accomplish simple repairs. With satanic designs like splined cranks, anybody can do thier own wrenching, and who wants that?

[Bradford]

Oh yeah, I almost forgot.

You know what else sucks about splined cranks? The reason I had to pull the crank yesterday was to put some touch up paint on the stay. On the second day of the PMC, our tandem hit a hole and the chain slapped up just when my stoker decided to crank down on the pedals, which wrapped the chain around itself. If we had one of those great square tapered cranks, we would have been done for the day and on the sag wagon. Oh, wait, the sag wagon can't fit my tandem, so I would have had to call for a ride. Oh wait, we were a two hour drive from my house, and my wife was with me on the bike, so there was no way to get a ride. Boy I wish we had a square taper crank. Our day would have been over, but at least we would have had a cool campy crank.

Instead, we just used the self extractors, popped off the crank, repaired the chain, and were on our way in about 25 minutes. That is so uncool.

[Rapid Tourist]

WEll, in case anyone is interested, my cranks are NOT TOAST. I decided I was outa my league and took the bike to Fred at Spokes. He said I had goofed by lubing the spindle of my square taper bb. So he wiped off my lube and he torqued the cranky bolt much better than me.

Lesson Learned: I am a wussy.

Its back to the gym for me to work on my noodly biceps.

Thanks to everyone!