Short question: is it critical to use the special tool (Shimanon TL-FC16 or equivalent) to install the non drive crank arm's plastic cap, or is a common sense substitute good enough? I used a pair of small needlenose pliers, spread the tips into the star shaped inner fitting on the cap and turned it in "strongly", but not enough to strip the plastic fitting. The crank arm is solid, the crank bearings move freely. I wanted to get the job done to ride the bike today, but could go back and re-do it if it's critical.
Long version: I installed a Hollowtech type crank for the first time last night. I thought I had every tool I needed for crank installation (I've installed various internal and external bearing cranks in the past). I have internal bearing tools, external bearing tools, a crank puller, etc.
I actually looked at the installation instructions online just before starting and I noticed I was supposed to have a cheap little tool TL-FC16 to install the little plastic end cap on the non drive side arm. Of course I didn't have the tool.
This just seemed like a simple thing to substitute for so I looked for commonly used handyman's substitute online. I actually couldn't find one!
I read various things about what that little plastic plug actually does. Shimano doesn't explain it, but does list a torque spec. I read that the torque spec is essentially a good, solid hand tightening with the FC16 tool. I read some people who said it's for "preloading" the bearings (and you'd know if you've gone too far because the bearings would be draggy) and others who said it's not for pre-loading, but rather for simply properly seating the crank arm onto the spindle, and that you couldn't possibly load up the bearings to "dragginess" with that tool.
Whatever. I didn't have the tool and wanted to get the job done last night, plus I didn't think I could find the tool locally and therefore would have to wait a week to mail order it.
Using "common sense" I thought about the torque value, the "hand tight" criterion, what the little tool looked like (the size and how much pressure "hand tight" would be), and decided that my little needlenose pliers had tips that would just fit into the star-shaped fitting on the plastic cap. I expanded the plier's tips into the inner indents of the cap, and carefully tightened it as tight as I could and was careful not to strip out or even mar the cap's fitting. FWIW, I think that given the width between my little needle nose's handles and the size of the disk that is turned on the FC16 tool, that a good solid "hand tight" with my little needle nose would be about the same as "hand tight" with the tool.
The crank is installed, the crankarms/spindle are solid, and it spins smoothly and freely. Set up on the stand, it shifts perfectly. (hoping to ride it later today).
What think you - is this a seriously critical item? Should I just be patient, remove the crank arm, get the tool, install the plastic cap "hand tight" with the tool and reinstall the crank arm after that? What should I look for? What's the real danger - ruining the arm? Ruining the bearings? (I'd prefer erring on the side of shorter bearing live vs. damaging the arm).
Is, in fact, the plastic cap for preloading the bearings (I'm skeptical) or just for seating the arm on the spindle?
I suspect I'm really, really over thinking this, but you never know! Thanks for advice, comments, etc.