Breakdown: The Repair

Last week I had my crank arm come loose on me. This was on the fixed gear set up I am using on my Twin Six Standard Rando v2. You can go back and read my post about this occurrence HERE in case you missed this. 

Since those plastic pre-load bolts are scarce in my world, I had to order a new one and I got it in on Tuesday of this past week. I also somehow misplaced my Park tool "wing-nut looking" installation tool for this special bolt. So, I ordered a new tool, but this time I got a Unior tool for the install of the plastic pre-load bolt which cost a lot less than the Park Tool one. 

While I was at it I also bought two of those excellent Lezyne side-loader cages I've purchased and used before. I'll likely do a separate post on water bottle cages soon, and I'll hold off on my comments on the Lezyne cages until I post that article here. 

Ordering a plastic pre-load bolt for a Shimano crank was not as easy as I thought it could have been. I ordered from Jenson USA, and their descriptions were sorely lacking for such a part. Without my background in bicycle repair, I may have missed a choice which - as it turned out - worked for me. I can easily imagine an average rider being very disappointed in the information, or lack thereof, for such parts. 

But Jenson has a huge inventory and who cares about a part that costs a couple of bucks? Well....you cannot run a Shimano two-piece crank set without that stupid plastic bolt, so it is kind of imperative for there to be clear information for consumers. That's my take. 

Making sure the bolts are torqued properly.

Installation is pretty straightforward. I did put a thread locking compound on the plastic threads of the pre-load bolt this time, just for a little extra insurance. We will see how this goes. 

Then I torqued the pinch bolts, using an alternating tightening pattern, to 14nm. It is important to note here that HollowTech crank arms are very intolerant to loosening or tightening one bolt all at once. That is a recipe for crank failure as the uneven loading will crack the arm. It is best practice to alternate when tightening or loosening these bolts, or with other similar set ups such as stems and some other components which use pinch bolt clamping force to stay attached. 

So far, so good. I rode the bike for a good half an hour to test the parts and see if anything loosened up. Next I'll do several short rides, test everything again, and only then will I be satisfied this is good to go. 

Which brings me to another point. Testing. Shop mechanics generally do not get to test a repair, and long term, multi-situation testing? Forget about it! So, most retail bicycle mechanics have to do their repairs not only quickly, but without any real assurance the repair will hold up, in some cases. 

Obviously most mundane repairs are not part of this discussion, but there are some things which only will be proven out, or diagnosed, with time and trials. Consumers are not very tolerant of this, but the reality is that if you want a very secure and trustworthy repair, you have to pay in time and in money. 

Don't blame your mechanic if you are in a hurry, or won't pay him/her what they are worth.