Originally Posted by
Duragrouch
Shimano: I heard the recall was the dealers inspect, if no delamination, they don't replace. I don't trust the assembly. It may have a catastophic failure mode (sudden and without warning), versus a graceful degradation failure mode (lots of warning, distortion, etc.) Those are actual engineering terms.
Shortening current crank: Well let's math this out: Pedal threads are 9/16" which is 14.3mm. 175-160 (center to center)= 15mm. So with those two holes next to each other, you have the radius of each hole intruding to that distance by half the hole diameter, which leaves only 0.7mm of metal on the outside end of the new hole. No, this will not work. You need to start with a long enough crank, so that when done, enough metal exists on the end of your new pedal hole, to equal what was there for the old pedal hole.
Chainline: You want the chain between the crank and the cassette to be as straight as possible.l.. (continued in a minute)
Maybe I'm not explaining it well enough. The crankset on my K2 is a Ritchey and there is probably around 1.5" of full thickness aluminum at the ends of the crank arms. The existing pedal holes are towards the end of that thickness and they are stamped as 175mm arms. Now, I admit I'm just eye-balling this but I would guess there's at least 3/4" of an inch of full thickness aluminum from the inner most portion of the existing threaded hole to the scallop. Could be more. Either way, I'll probably take some measurements after work this week.
Kind of surprised regarding the Shimano recall. I guess they don't figure it's likely to be a life-and-death kind of failure.