Crank Arm Problems

luke_mccarthy

Hi,

I bought a Giant XTC 3.5 last summer and within the first month (ish I can't remember how long exactly) the left crank arm came loose, I tighten it up as best I could with the cheapy multitool I had with me at the time, this wasn't good enough and it came loose several times on the way home damaging the spline. I took it back to the LBS where I had bought it and they overtighten the bolt (my assumption) causing it to snap off next time i was out. I obviously chucked it back at them and they replaced some parts, unfortunately i don't know what exactly. End of part one!

I countinued to use my bike without any problems towards the end of last summer and then on a turbo trainer a little through the winter, now the weather is picking up I have done about 150 miles this year and on my last ride it came loose again. I managed to tighten it and it stayed tight for the rest of the ride, although this wasn't long. So a couple of questions:

1.) After 8/9 months and a few hundred miles can I take it back to the LBS as a problem with the repair they did?
2.) As this has happened twice in relatively quick succession on a new bike is there likely to be a bigger problem that is causing the crank arm to work itself loose?
3.) Will locktite and a lot of torq to tighten it work as a long term solution?

BTW the chainset is a TruVativ ISOFlow 3.0.

Thanks if you read the essay and any help would be much appreciated,

Luke

nicklouse

if it is the Powerspline version you have got away quite well.

you could try going back but it all depends on what they actually did.

Long term solution replace the cranks and bb with an shimano external bearing set.