Lost the plug that snugs up a Shimano NDS crankset installation

[DRZRM]

So I was swapping out XT cranks to my brother-in-laws bike and XTR cranks to mine, and I realize that I likely tossed that plastic plug--the crank arm bolt--that snugs on the NDS crank arm before you tighten down the bolts that hold it in place. I had one between the two cranks sets, and I was able to snug up the crank with it and start to tighten the crank with the allen bolt, then extract the plug and use it on the other bike. Seems like I have both cranks properly installed.

Is there a problem with installing this way? Seems like a headset top cap, it holds everything in place while you snug up the stem, but then it is not really important, right? I will order a replacement (or post a WTB) but there is no issue using the bike without the plug in the short term, right? Or am I missing something?

[mktng]

i want to say it does serve a purpose and would be best to have it upon installation of NDS arm. avoid having the crank arm fall off mid ride.

your lbs should have spare though. no? seems like a part you could find in the parts bin. i know i have one off a 7800 crankset spare....if that fits (doubt it) id be more than happy to ship out to you.

[Davist]

LBS has them, mine did, as I did the same thing. Once pinch bolts are tight, to your point, you *probably* don't need it, but it's like a $3 insurance policy.. You can get them in metal, too, which I did..

[d_man16]

Many, Many K's w/o problem also with a striped out NDS just clamped down the crank arm bolts works like a champ (cobblers children wear no shoes {ex mechanic} and I'm way cheap too)....Heck the steerer and bars stay put. That little plastic clip between the bolts should keep the arm from falling off.

BR,

~D

[Bob Ross]

Originally Posted by DRZRM

Seems like a headset top cap, it holds everything in place while you snug up the stem, but then it is not really important, right?

Also just like a headset top cap, it preloads the bearings -- in this case, the bottom bracket bearings -- and so in theory it requires a bit more attention than just "it hold everyting in place temporarily until the bolts are tightened"

...but since I never bother using a torque wrench to preload the bottom bracket bearings, I'm just talking ideals.

[ofcounsel]

Originally Posted by DRZRM

So I was swapping out XT cranks to my brother-in-laws bike and XTR cranks to mine, and I realize that I likely tossed that plastic plug--the crank arm bolt--that snugs on the NDS crank arm before you tighten down the bolts that hold it in place. I had one between the two cranks sets, and I was able to snug up the crank with it and start to tighten the crank with the allen bolt, then extract the plug and use it on the other bike. Seems like I have both cranks properly installed.

Is there a problem with installing this way? Seems like a headset top cap, it holds everything in place while you snug up the stem, but then it is not really important, right? I will order a replacement (or post a WTB) but there is no issue using the bike without the plug in the short term, right? Or am I missing something?

The cap is to preload and snug up the crankarm to avoid play. It's like a headset cap. Once you have the right amount of preload tension, you can ride the bike without it, as long as the two crankarm bolts are in place. It will just look unfinished, is all.